Suggestion: I was hanging out with a neighbor who was using his oil-barrel smokeless incinerator and his has a few additional features: 1. an internal 45-degree bevel that redirects the air rising up directly to the upper holes, and 2. an external bevel just like #1 but more like a beveled lip just above the holes to slightly narrow down the fire pit/incinerator opening and giving more time for the secondary air supply to mix with the smoke and make the secondary combustion more effective. The external beveled lip is around 1.5 to 2 inches in width which at 45-degress should only narrow down the fire pit opening by a total of 1.5-2 inches. I was surprised his incinerator hasn't produced any visible smoke at all and I just thought that those features might have helped.
I like the fact that he didn't edit out the mistakes he made and what didn't work in order to demonstrate how the various changes effect the outcomes. Great video!
Absolutely that way if the next person thinks that what he did is the best way they can see that it's not and it'll save them time and headaches. They say that failures are steps toward success.
Why wouldn't he... you people were paying him to experiment... it cost him nothing and he probably made thousands above what it cost him... not to mention he had a sponsor paying him...
@@t.c.2776 I suppose for the same reason 9/10 youtubers edit out any flubs, mistakes, bloopers, mishaps, and anything else that may not project a polished and professional appearance to their audience.
I appreciate you doing all of the homework and expenses. Saving me time and money. I'm a single dad, and I enjoy doing little things like this with my daughter to show her love. Burning firewood and hugging my little one is so great. Every dollar counts, so thanks again.
My daughter has also been quite enamoured with our fires we build together. She has expressed an interest in doing some branding. Next weekend we will try just a small quick one on her right hip.
Easier to show love for your kids AND your family by not having kids in the first place. Too late to save you but maybe someone else will read this and find some common sense for once in their lives.
Just had to say one of the best integration of a sponsor and not taking the whole frame of the video and giving us continued progress of the project at the same time! 👏👏👏
THIS! I appreciated that you didn't take a break or tack the ad on at the end. And honestly, that meant I heard the entire ad. When I see ads on other videos I just move on or fast forward.
I'm thinking the only thing you could have done that would improve the performance of your fire pit is more depth. The Solo stoves are much smaller in diameter than your fire pit and they are taller in height. That gives much more space for the air to really heat up as it rises from the bottom to the top of the air channel. Great video! I know I learned a lot by watching it.
Yes, and the fire needs to be big enough to really heat the wall of the fire pit. This makes it so the air gets proper flow and is superheated so it really combusts the smoke. I own a solo stove and it works really great, as long as you keep it properly fed. When it's really hot it burns green wood mixed in without any smoke.
0:27 fun fact! (Assuming you don't say it later) the reason smoke seems to always be blowing into your face is because of convection. With nothing obstructing the air's movement toward the fire(and no wind) the smoke will rise straight up. BUT! since there is often a person or group of people somewhat clumped together around the fire, the air that would come from behind them is slowed meaning the air on the other side of the fire that isn't slowed will assert more force bending the convection current and thus the smoke towards the people blocking the air. Of course with the wind blowing the smoke will follow the wind but still be affect by the convection
This is why I often add a large, flat vertical stone on the far side of a campfile fire. However it doesn't aways work, because smoke following people is based on the universal law of attraction... whatever you fear will come :)
Really liked your pit design. There is another way to have a less smokey fire. You don't construct a tipi. Instead you pack in tightly the logs at the bottom. You add smaller pieces and at the top you construct the twig, pinecone, dried orange peel pile. One lights the top, not the bottom. The fire burns gradually downwards but having the fire at the top means it burns the gases coming out of the gradually heated logs. Much less smoke and significantly more heat.
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The amount of work, time and investigation you went through to figure out how to exactly create the closest thing to a smokeless fire pit was pretty impressive to me. You went beyond my expectations and I appreciate the days it took to film this and do all the drilling, experiments & etc. I’m subscribing for more of your videos. Your thoroughness in figuring out the perfect method will save me so much time and error.
Tip for calculating the airflow: Measure your 4 gaps in the bricks. That's the surface area of the inflow. Ideally the outflow should be similar in size to the inflow, or slightly larger. Number of holes * pi * diameter is the surface area of the exhaust. Compare the two numbers and then adjust the hole size (or number of holes) until the inflow area matches the outflow.
Would you want the airflow to be the same between the top and bottom? Would it not eventually choke the fire if the bottom weren't receiving more air to feed it? Or would the heat of the fire just naturally pull in more air from the bottom regardless; provided the holes weren't smaller and/or less numerous than the top holes.
Surface area of the exhaust = (number of holes) ⋅ π (diameter / 2)² (Number of holes) ⋅ π ⋅ diameter would give you the total circumference of all of the holes, not the total area.
@@flennboyd6413Probably Automotive Engineering or Furnace tech/engineer. There's a big world out there man, lots of really cool things that people do.
There is one detail about fire pits that people keep forgetting. If the fuel (firewood) is higher than the secondary holes, the secondary burn will become a primary burn for said wood and thus produce smoke. If you want to keep your current system then do not build the fire higher than the secondary holes (maybe an inch shorter). If you are going to mod the system, add a 4th layer of stones and keep the firewood below the holes.
Wow! I have zero intentions of doing this to my fire pit. I don’t even know how this video found me. But, I certainly appreciate the amount of time, money, and work you put into this video. You’ve earned a like. Great job 👏
I agree with everything @scottvriethoff6633 said. My hats off to you FIX THIS BUILD THAT for all the labor and money you put into this test for others to benefit.
This guy is brilliant! How beautifully he explained the various tests he conducted! He was so determined to achieve the objective of building a smokeless fire pit, and he finally met the objective!
Actually the solution is a three quarter size burn barrel, with a lid ( that opens) and a pipe that has a flue… perfectly distributed heat, no smoke whatsoever .much better heat source ..use it in backyard for gatherings and at hunt camps
@@brentfarvors192 its too wide to properly work, the air needs to get hotter so it will rise above the smoke, taller narrower versions do actually work to some degree
Meh... do a search for 'dakota fire hole' or 'dakota fire pit'. I've been building low-smoke fires most of my adult life without anything special. You just have to watch the wind direction. Air feed is the key along with a hot fire.
I think the next step in efficiency would be to add spiraling channels around the outside so that the air in the walls of the fire pit can't just go straight up, but has to go at like a 45 degree angle around the outside, increasing the time it spends in the wall and therefore the time it spends heating up. This would likely result in a secondary burn happening sooner after starting the fire, and a more complete secondary burn due to potentially increased velocity.
Another feature to help secondary burn might be to add a lip above the top holes, as is seen on the retail fire pit design he's imitating. This would force the air exiting the top holes towards the fire a bit before it can rise above the firepit, along with adding some radiative insulation to that region to help keep temps up and maintain the secondary burn
Brad, your relentlessness toward seeing a job through to the and and your relentlessness in maintaining a great attitude is one of the most inspiring things about you and this channel. It is easy to see it is not a show for the video - it is authentically you. Thank you for all you do and the videos you make - this is truly one of my favorite channels in the maker space. Keep up the great work man!
@@Fixthisbuildthat Hey Brad, I’m totally high jacking this comment just to ask you a question. In one of your videos I heard you live in the Nashville area. If this is correct, I was wondering if you could help me out. I’m wanting to build a “big girl bed” for my soon to be 3 year old daughter. I don’t have a workshop and am looking for an easy way to build this twin bed. Reply back and let me know if there’s a possibility you could help.
What you tried to build is a gasifier stove. However, that design relies on two things: small enough diameter to heat up the walls, making the secondary air rise up by draft, and small enough diameter to deliver that air into the flames. It's not really well suited for a large but flat firepit, but kinda works if you make the fire crazy big, as seen.
I'd argue that one thing the pit would benefit from would be for the bottom airflow to come out from _under the logs._ In the current iteration, it just tries to get to the flames from the sides, which is better than trying to enter from the top, but you still get convection pushing most of it upwards, rather than allowing it to get near the actual fuel and thereby replenishing the oxygen levels more effectively.
Yeah, I was just writing about diameter/height ratio - and drainage: seems likely to collect water when it rains, and moss and a little ecosystem! The DIY double skin drum I saw on here before I saw the solo stove advertising everywhere - that had legs built from the base of the drum. Rocket stoves have built in thermal mass and, like, hardcore substance - as do pizza ovens. Which is kinda what you want in a garden feature. Even though the solo stove looks very futuristic, it's not everyone's vibe and it probably dents and tarnishes as much anything else. And a drum is already a relaxed & utilitarian DIY vibe. Not pretty.
Loved this, I have a Solo fire and it does smoke to begin with even with dry logs. You also get a better secondary burn with a full fire across the width (rather than a tall fire) as the air passing along the side to come up through the holes is heated more... Great job!
One suggestion I would make to reduce smoke, indoors or out, is to build an "upside down" fire. Put the biggest pieces on the grate, on the bottom, then the next smaller, at a right angle to the biggest ones. Keep alternating layers, leaving some space between the pieces for air, then put newspaper and small kindling on TOP, NOT on the bottom. You may have to feed a bit more small kindling at first, but not for long. You will be amazed at how much cleaner, quicker and hotter the "upside down" fire will burn. Each layer heats the layer below as the fire goes DOWN (trust me, it will, even though fire generally does go up), so each successive layer burns readily, and there is hardly any smoke. When you make a fire the usual way, the bigger wood on top isn't hot or dry enough, so there is quite a bit of smoke until the big pieces get going. Once the "upside down" fire gets down to the bottom layer, you just feed it more wood on top as usual. If you try this method once, you'll never go back.
We always do the stacked cabin type fire with the newspaper or kindling underneath the “roof”. I’m going to try this way next. I’ve actually never heard of it before.
In most cases this will not work. Heat rises. Ashes smother flame. If you need to get a fire going use log cabin or teepee style. Some genius taught this method to our kids for 'winter survival'. Apparently cold branches won't burn this way. Everyone had to eat cold weinies.😥🍖🥶
My metal chimnea just rusted out and we were talking about putting a fire pit in. I just ran across this video. Thank you for figuring this all out for me!😄. I’m going to talk to my family tonight about building one just like yours. I promise to tell them it was you that figured it all out!😄😄! Thanks again!
Oh my gosh! I just figured out my love language is smokeless fire! Thanks so much for your attention to detail and showing your process, can't wait to try this on my fire pit that came with my house!
Great video! I liked it! Here's what you missed when you looked at the patent for the solo stove. The secret of why it generates almost no smoke isn't to do with the size or number of holes in the top/bottom. That is a factor though. The biggest factor is to look at the ratio of the height of the pit to the circumference. Basically, the solo stove is skinnier and taller. With a pit of this diameter, you'd have better performance by building the height of the pit upwards. This increases the effective space of that insulating layer, providing more area for smoke and gasses to slow, cool, get trapped.
I'm usually not huge fan of these videos but you by far have a great presentation that would actually help people that have very little experience making things. If want I'd give few simple ideas to maybe make that an easier set up work better or you might take the things I do make them better. I just been working way to many hours and really just learning the video stuff
Fun video. I like how you showed the basics for the build but cut out the fluff yet still showing each of the different tests without just cutting to the finished result. Excellent!
Great video. It would have been good to see the unmodified original version with the same dry wood you used at the end. As I feel like that's what actually made the difference
Yes, correct me if I'm wrong, but nothing seemed to work until the fuel type and amount changed. So the conclusion should be: don't change the pit, just dry the wood and add more. I like the attempt to engineer the pit though, and I'll probably do something similar because it's cool :)
I dont even have a fire pit but this video was suggested to me. I loved your energy and it was perfect editing, i love how you integrated the sponsor in the video while showing you drilling the holes and not making it just a seperate segment
I have a different brand than Solo and it is completely amazing. Really cool almost welding type flames coming out of the sides at the inner top and bottom. Some smoke but only on super wet stuff (I've burned mulch). I have 3 problems with the setup. 1) They are all very tall so its not really a firepit feel. 2) they are completely closed in except at the very top so heat is focused basically completely up. So they are not as warm either. 3) wood burns really well and super hot so it also burns fast. It's all very impressive physics and thermodynamics but it does not feel like a campfire pit type thing. Feels very "efficient factory produced fire that can melt metal." haha great video!
Good observations. I wonder if it would help to suspend a flat plate above the fire? Theoretically that should redirect the hot air toward the outside of the firepit. I expect that the fire will eventually destroy the plate unless it’s made of ceramic or fire brick or something. And I wonder if a cone sticking out of the middle of the plate might encourage more even distribution of the hot air than only the flat plate. Seems like there should be a way to get the benefit of the efficient, smokeless fire without losing out on the warm, comfy firepit.
You are amazing. So much integrity. You didnt edit out the hard work and mistakes and you listed your references! So many tubers dont do that. Anyway, the results are there, Id like mine to be even wider and more shallow. I might just sacrifice some smoke - maybe. TY
the smoke is always in your face because the smoke will travel towards the tallest things around the pit. Think of it as smoke traveling up a wall. At one end of my pit I have a tall rock (almost 4ft at the peak) I am not sure the science behind it but this makes the smoke always migrate towards it and then up the rock and up. Just something to think about. great build as usual.
Air rises over the fire, pulling outside air towards it. You block that inflow, so rather than it flowing in to the fire it can get pushed out towards you
No your body acts like an air dam. It blocks air from getting to the fire . What creates a vacuum and the fire smoke moves towards you. The more people that sit around you the bigger the vacuum. So sit alone and the smoke will not bother you.
Yes, the stacking of the wood has more of an influence on the smoke compared to the fire pit's design. What works for me is stacking the wood to create a closed high temperature chamber, like a furnace, with smallish entrance holes for the air, and corresponding exit homes for the smoke.
Great video. However, the part that's missing is the ratio of stove height to diameter. There a powerful convective element with this process you just aren't going to get with such a wide and shallow fire-pit. The point is to increase the secondary burn which takes place at the top of the fire. In your stove the top of the fire (flames and smoke) is already outside of the fire-pit. It's just NEVER going to work like that. You pit needs to be 2 or 3 times higher for that diameter. Notice on the patent how the top is tigher than the rest of the pit and the ratio of heigh-to-width. The secondary combustion has to take place BELOW the top surface of the stove. Dry wood for the final tests but wet wood for the preliminary is also quite misleading. A lot of people will fail following this advice.
You brought up a point that I was thinking. The idea that he is copying does have a higher ratio, meaning the fire pit should be taller. Everything else about this is good and I think I'll build one of these.
At first I was ready to rip out my stainless steel insert on my garden BBQ (we don't call it a fire pit) and spend a Saturday in May drilling 2500 holes...thanks to this post I'll save the effort...title of the video should be wet wood is great for smoking
Super fun project, Brad - had me glued to the screen start to finish! I hadn’t really heard of smokeless fire pits unless they were propane or gas fed so that was pretty rad. Great video!
@@Dgiztred Yes. My "experience" is exactly as posted; The ONLY WAY to control the quantity of smoke, is to burn on a clear (high pressure), windless day, using the driest and most finely cut fuel available...Using the method posted here will make the fire burn HOTTER (More air flow= A hotter flame), but will do NOTHING for the smoke; Especially when starting the fire, and when it starts to burn out...I've tried with Pits/Barrels, and everything in between; You aren't going to beat physics...
For that design, smaller fires will be more prone to smoke. That's why the large fire worked better. The fire has to be large / hot enough to heat the air in the gap so that it's primed for secondary combustion when it reaches the holes at the top. For that you either need a hot fire, or taller walls to allow my travel time which equals more heat.
I rarely get heavy smoke with any pit, but it’s because of box fire in conjunction with tee pee style. It creates it own vacuum the hotter the fire the faster it’s heat is ejected along with its smoke. Needless to say, I like raging fires. Fill my truck bed once every two months with good dry wood.
When wood gets hot enough in a low oxygen environment, it produces wood gas, which is flammable. Combustion needs oxygen, so you see fire "shooting out" of the vents, which is actually the boundry of wood gas and oxygen mixing and burning. Gas burners have this same boundry flame, but inverted, with a stream of flammable gas into an area of oxygen. Fun fact, the fire we see is mostly comprised of incandescent soot, material that gets so hot it glows like a lightbulb or forge metal.
So it's true that wood doesn't burn. It gets hot and produces flammable gas. If you look very close to wood burning there is a slight gap between the wood and the flame.
Correct, if you're seeing flames out of the top holes, it has to be wood gas being drawn into the lower holes, & mixing with the air to then be ignited as it exits, looking like the burner you talked about. Just air coming out wouldn't really do anything... My woodstove has secondary burning, but the flue comes outta the middle of the firebox (damper can be slid open to load wood, so it exits the stove by flue not door, lol)
If you notice on the Solostove the top opening is necked down smaller than the diameter of the main burn chamber. That increases the velocity of the air leaving the chamber and this increased velocity produces a slight vacuum in the chamber. The vacuum pulls more air through the secondary combustion holes making a more efficient second burn and less smoke.
I don't even know how this video popped up but I had to watch it all. I do not even remember what my initial search was, but it had nothing to do with firepits. But now i want one again. Great effort! Relentless! 👏
I have made similar fire pit from the laundry inner tub, which has tons of holes. It works great with no smoke. It seems like in your experiment, the fire pit is too low so it doesn't allow much of the air flow. The upper holes should be at bit higher. Thank you for the experiment and share!
@@bam5732 - They both play a role....Even with the driest wood, you'll still get lots of smoke if the fire doesn't have an ample oxygen supply. Likewise, even with the best possible air supply in the word, if the wood is wet it's gonna smoke. It would have been nice though if he'd actually shown the old pit with dry wood.
@@scottcates most of the time they are stainless steel, or at least the older ones are. Also, the older ones are driven by a big pulley, which can be left in place and serve as a stand. :)
dude tried it with a wet wood, did bunch of improvements that didn't help. Eventually he added dry wood and omg - it didn't emit as much smoke as it used to. Definitely a good design :D
It would be interesting to have done a control burn using dry wood before drilling the fire ring holes. This would show how much of the improvement in smoke reduction was due to the modification of the fire ring and how much was due to the drier wood. Great video otherwise. Very easy to understand. Will use your tactics when I build my next fire pit.
Pretty sure it would be exponentially better if you placed a another layer of stones on top of the steel liner to add as a "ledge" so that the top opening is a little tapered.
He’s onto something here. By narrowing the top of the fire pit, you will achieve what is known as the Bernoulli effect. A greater force of air thrusting through the whole system, and theoretically more fweefwee
After doing this project years ago, what I learned was it's easier to get the smokeless results with a smaller firepit ring. I think this is because in order to get smokeless results you need higher temperatures which is easier to get with smaller pits, unless you plan on burning A LOT of wood at one time. This is probably why the solos aren't that big.
If you ever decide to return to this project, you could place a small lip around the top of the internal circumference of the pit forcing the air for the secondary combustion in rather than straight up as it exits the holes while simultaneously trapping some smoke underneath the lip which may increase the combustion but also possibly reduce the airflow. I am curious to see the effect. It's a similar approach the reducing the diameter of the pit without making it look like a soda can.
Thanks for making this. I used your first video to build my firepit recently and it's producing way too much smoke so will definitely be giving this a go!
Great video and tests! Love the tape idea for drilling, I'll remember that. For my outdoor fireplace, I added a 12V 4" boat bilge blower underground, contained in drain pipe that draws air in from about 8 feet away and exits under the center of the pit. When I need to get the fire going quick, or reduce smoke, I turn that on (hooked up to a 120V to 12V adapter and a smartplug) with my phone app and boom...raging fire and no more smoke!
I'd like to see a video on that! I've thought about doing something like it for my fire pit. How do you keep water out of the air duct? What did you use for the duct to keep it from decaying from the heat?
You will eat a LOT of wood that way. Just make pit smaller so coals air mor in contact and heat that metal more. As I posted above 450F is minimum to get secondary burn.
Brad, the best part was you used the lighter, when the fire was already going. I love it man. Seriously. it shows we're purpose driven humans...I have a need..I have a tool..I'll use the tool. Haha Nice video!
Probably could've saved 6 hours of work by switching to dry wood. I burned very old and dry oak flooring last night in an open pit and it was smokeless.
I've watched all of these hoping that someone will get to where they "somewhat" match the commercial available ones. This is getting it a step closer! I think, and I could be way off, that possibly these DIY self attempts are not matching the height/width ratio of the commercial ones. Being so much wider, I wonder if the air going up the sidewalls doesn't have enough time to heat up. You need a much "wider" fire to heat the sides, and the air traveling up the sides is so short. *** BIG CREDIT goes out to all those trying.
yes, 100%. I don't think I'll ever get the consistent secondary flames on this design because it's so short. The air doesn't have enough time to get superheated consistently. A taller smaller version would be much better to achieve that
@@Fixthisbuildthat I don’t think your fire pit is too short. It’s too wide. Over the years my family has owned a solo stove and two breeo fire pits. We’ve learned that smaller diameter fire pits make it easier to produce a smokeless fire, and they consume way less wood. Consider fabricating a wider top ring that reduces the inside diameter of the opening and covers the upper vent holes, protecting them from wind Lastly, spreading coals closer to the walls and adding logs to the perimeter reduces excessive smoke much faster than keeping your fire centered Great work! This is one of the best DIY smokeless fire videos I’ve seen
I think that having the same air source for the primary and the secondary burn is an additional 'mistake." You want the secondary burn air to heat up and exit the top holes with pressure. Having the primary air come from the same flow reduces that pressure. Notice how the patent separates the airflow much more distinctly.
Everyone saying it needs to be taller or skinnier is alluding to the fact that there is an optimal way to make this fire most efficient AKA not have any smoke. You are right, but the patent exists for a reason, there is much more thought/calculations and actual enhineering going on behind the scenes that would take more than just winging it with random materials. There is a lot of thermodynamics and heat transfer going on here that isnt as simple as “just make it tall and skinny” because there is obviously a sweet spot on both those constraints.
Or, more likely, your original fire was simply too small for the size (and wetness) of the wood you were using. You'll note that in the 'after', the fire is substantially larger than the 'before'.
Dude I've seen so many DIY videos and they're all good, but you had me so thoroughly engaged. I was locked in each step and was so eager to see the successful outcome. Great video.
The way you took a scientific approach was great and the colored smoke bombs were a brilliant. Nice work as always. This had to take about a week of experimenting to do all that and I appreciate that.
I really liked your video, I've watched many and this video was the best. I loved how you actually tested the different size holes until you got what you were shooting for. I've got a similar situation and wondering what size the bottom holes are and how far down from the top are the 1/2" holes and how far up from the bottom are those holes? Thanks!
Seeing how the air travels by using the smoke pellets was cool to see and helpful to see what size hole works best. I’m making a smokeless pit right now and this was very helpful. Thanks!
Try arranging your logs into a lincoln log cabin style. lay 2 wood splits parallel to each other and then stack 2 more splits parallel but perpendicular to the bottom splits. like a tic tac toe cross. helps promote airflow! I use that technique when i smoke meat! Great vid Brad!
That and getting it large enough to cause secondary combustion. Big fires burn hotter. I have a 24 inch Breeo and am astonished by the amount of wood it burns through. I can't imagine the 30 inch version!
I think the geometry of the fire pit may have a lot to do with it. Smaller diameter and/or taller pit. You want the steel wall closer to the fire to transfer more heat into the incoming air. Taller wall gives the air longer to get hot on its way up and out.
This is what I was thinking the whole time. His fire pit is way too wide and shallow for this application, and using extra dry wood for the final test means his before/after doesn't mean much. If you build a super hot fire with super dry wood you're not going to have much smoke, it has nothing to do with the "smokeless" pit.
Its definitely the geometry of the pit. The way the solo stove works is that the upper air vents provide fresh oxygen to hot, combustible fuel and burns off any solids. With the current diameter of his pit there is too much room for a heat gradient to form, this causes the upper air vents to pool cool air into a region of cool air and smoke.
I came here only to look for someone that has noticed the wide diameter of the fire pit. Definitely, an underrated perspective looking at the rest of the comments.
It's heating the air that's injected at the top that stops the smoke. The hot air hits the smoke and combusts. Same system as "clean-burn" log burners. I think you struggled a bit until you put tons of wood in due to the size of the metal ring. A small one heats up faster and gives more heat to the air being pulled in.
We did something very similar by leaving bricks out of the bottom layer around the outer ring to create air gaps, and then I put regular brick [yes I know could've/should've used fire brick] flat on the ground with expanded metal on top of that to ensure constant airflow under the fire. Also using an old washer drum works really well. Cool video btw.
When I moved into my new house I wanted a smokeless fire pit. I happened to watch this video. I modeled mine to yours. I used the 1/2" holes on top and bottom, 1'-1/2" apart. I have to tell you, man. My girlfriend and I are very happy with the work we put in! Not only that, I showed some of my carpentry friends, and they want the specs. This was a great build! 👍 also I got them flames out the top holes
the main factor i've noticed when it comes to smokeless fire is temperature. the hotter the fire, the less smoke gets produced. So when you look at the before / after at the end of the video, you can see theres alot more wood in the after, more flame, more heat - less smoke. Airflow obviously is a huge factor when it comes to fire, and also temp of a fire. im not entirely sure if there are any other factors that go into smokeless fire other than temperature and airflow by extension if i'm honest, but you can get really good smokeless fires just by dumping metric butt tons on wood onto them without much real thought.
Awesome video Brad! I always think of your videos from the perspective of your neighbors and it makes me laugh. “Honey, looks like Brad is lighting the 47th fire of the past 24 hours, let’s see what happens with this one!” 😂
I think your Math's off a bit. In 24 hours we would not have but twelve or so of 'daylight' and fewer of the sort of light seen in the video clips. Lets say, ten hours or 600 minutes MAX. Allowing for time to load the pit, start each fire and get a respectable burn going would consume not less than ten minutes per instance (in a dream world perhaps), leaving but 130 minutes for the forty-seven video clips or 2.7 minutes per clip. The first fire and smoke (edited) clip ran a minute twenty plus with several obvious cuts/clips cobbled together along with some quite rapid talking. Let us assume it took significantly longer that 2.7 minutes to film that first clip. Now, between takes, we need to cool the pit down to remove the ash and such and reassemble things, add combustibles, ignite, etc. Then there is all the work to perforate the ring - not starting fires then, was he? Not sure where he lives in TN, but outside of town with a few acres, folks don't pay much attention to their neighbors - esp if they have Cable and Internet and a place to take care of or a job in town.
Smaller solo stoves get a much better secondary combustion. I have one and I've made a tincan version as well. The tincan one worked just as well. So basically what I'm saying is that a smaller fire ring would give a much better secondary combustion. Large holes on the bottom small on the top. What else could have worked even better here would be to put a raised grate lining the bottom to allow more flow through the inner chamber and up through the secondary holes. Great video though, I'm going to build one i think as well soon.
The fire shooting out of the holes is actually the wood gases burning. Honestly, fire ring is too large a diameter, and not tall enough to create those jets...It takes convection to create them, and the larger diameter keeps that from happening consistently around the ring.
Thank You for sharing. I really appreciate your experimentation and exploring and showing me/ us your results. Makes lots of sense. I am planning to add one to my backyard soon and I hadn't even considered the smoke element. Until I came across your post. THANK YOU THANK YOU THANK YOU 😊
I use an old washing machine tub for a fire pit. It's stainless steel and it has a ton of little holes all the way around it. I always get flames shooting inwards through the holes. It's super cool to see.
Wow, this is EXACTLY what I was looking for!!! Great video, thanks a bunch!!! Oh, and also, keep the flame going at all times, it helps burn up the smoke!😊
I think a big part of the efficiency of the patented firepit unit is its size. Your fire ring is bigger, meaning there's more air in the middle to heat, the fluid dynamics of the air flowing through the holes may work differently, etc. Compare with the extremely upscaled version where you have a 6' diam fire ring but the same heights, same size holes around the rim, etc. I think their patented unit just has an optimal size ratio for smokeless fires given a particular expected fireplace height.
I think this is true as well. The SOLO stove is smaller in diameter and also taller, forming more of a chute and channeling the heat better There are flaws with the SOLO design that lead me to not buy one, but I'd like to reverse engineer it some day and build a better fire. But ultimately, it's almost impossible to build a smokeless fire if you use wet wood. The wood just can't get hot enough.
A lot of time and effort to make this video! A BIG THANK YOU! Had a fire pit at our summer home and always wanted to figure this out. You did it. Great personality!
Wow 🤩, the amount of effort you put into this video making that fire pit is that of the top home improvement professional! I didn’t think I’d enjoy watching this so much. 😂 I need to put more effort into my fire pit now. 😆
Interesting experiment, Brad. Keep in mind that equivalent area of holes doesn't equate to the same flow through them. For example it takes more than four 1/2" holes to equal the flow through a 1" hole. That's the engineer in me coming out now. Bill
Yikes, there is a lot more science here than I had conceived, but the rewards are great…nothing worse than teary eyes around the camp fire, thank you for showing the way!
Nothing worse than teary eyes around the camp fire? How about if someone fell in the fire?! That's third degree burns, KIRK! Sheesh, you and your first-world problems.
I used a double walled stainless steel washing machine tub to make a fire pit in 2008 and it worked just like this. it was incredible. Wish I'd realized what I created and commercialized it....
Diameter vs. how deep the firepit is, seems to be your main issue. Also, you could try making a bed of the firering to force the air intake to exit closer to the center of the firepit. EDIT: DAMNIT, bumboclat was 22 hours earlier than me! EDIT2: Also, another way of improving would be, assuming you make a firering bed as I suggested, would be for iron rods to entertwine with the middle of the firepit - this would act both as a way to easier set up a fire, but could even be bend into being able to support a stove - as well as absorb a lot of the heat from the fire, and since it being iron and connected to the firering, also heat up the firering quicker, and more, which in turn would make the firering more effective at pulling air to the upper holes.
analyzing stuff and discovering what forces are at play is one thing... balancing those forces to obtain the perfect result is a whole different ballgame.
I think the big issue is your secondary air that goes through the top holes is cold. The stones cool the air too much and it is exiting the holes too cold to ignite the smoke. You saw this correct itself when you allowed the fire to burn for a while, which allowed the stones to heat up, and then produce secondary air that was heated. I believe the better solution is the one that is already out there. You need to have two rings and a small insulating air gap around the outer. The air traveling up between the two metal rings is going to be be heated faster and hotter.
In addition to your trial and error on the fire pit, I will add that the "Lincoln Log" stacking of wood is much better than the "teepee" method of stacking with respect to air flow and reduction of smoke. I have been wanting to make my own fire pit for a while, and I will be sure to follow these plans/ideas when I do someday build mine.
I'm inclined to agree. Early Spring of 1996, while playing with my modified Chemlab kit that I had received as a Christmas gift months earlier, an unfortunate reaction occurred and sent flaming liquid down the side of the workbench right on to a pretty elaborate lincoln log fortress that I had created. The blaze only lasted about 3 minutes but the absolute carnage was noteworthy. The lincoln logs created a perfect environment for mass combustion. The workbench and wallpaper were damaged. Carpet ruined and about 70% of the log fortress was unusable afterwards. Several action figures were lost in the fortress(RIP to Snake Eyes, Destro, Baroness, Wolverine and Omega Red).
One of the differences from the patent and your fire pit, is that in the patent, the bottom inlet air is going underneath the fire. Yours is just going to the base of the fire, so anything not near the sides won't get enough oxygen. With a grate that keeps the fire, or most of it, off the bottom of the pit, you'll give the inlet air opportunity to go underneath the fire. That might take care of the small amount of smoke.
Enjoyed the heck out of that video! There’s a surprising amount of engineering in that little fire pit - thank you for posting this - was thinking about doing this over the Christmas break - thanks so much!
I think your fire pit is just a bit large for how low it is so you'd need an absolute inferno in there to get the secondary combustion really shooting out flames. You need the height to give the air more time to heat up and to separate the secondary flames from the primary fire
I'm surprised that he didn't understand this concept. It's kinda like watching someone try and copy the design of a car, without understanding how a car actually moves. You can put four wheels on a frame, and add a pedal. But if you push the pedal, it's not gonna do anything UNLESS you also have a drive train. It might LOOK like a car from the outside, but it's missing the science under the hood. His design is fine - it's just massively oversized, like you said. He's never gonna get the temperature differential necessary to cause the draft he's going for
@@zp944 Well, air does heat up quite fast tho so it might be easy to overlook. I'm not an expert on any of this so even though I'm kinda confident in what I said I can't really back it up with anything else than 'That's what it looks like to me' :D
To have a better effect of smoke-free fire pit. The walls and the fire should be close together. The smoke free is due to feeding fresh oxygenated air to the base of the fire, to help with complete combustion. See a Dakota Fire Pit.
Apart from the diameter issue, the solo stove has a rolled in top lip which shapes airflow. You can approximate this with a cap ring as long as the upper breather holes are set at the right spacing (I suspect it's 1/3 the internal overhang down from the top edge in order to get the right rolling turbulence to achieve good secondary combustion)
I think the cap is what helps guide the top air holes into the heat to combust. With the cap ring off or upside down it won't have the secondary combustion.
Watch this next: Will Concrete EXPLODE in a Fire Pit? - ua-cam.com/video/TJP4iQlV8qU/v-deo.html
Suggestion: I was hanging out with a neighbor who was using his oil-barrel smokeless incinerator and his has a few additional features:
1. an internal 45-degree bevel that redirects the air rising up directly to the upper holes, and
2. an external bevel just like #1 but more like a beveled lip just above the holes to slightly narrow down the fire pit/incinerator opening and giving more time for the secondary air supply to mix with the smoke and make the secondary combustion more effective.
The external beveled lip is around 1.5 to 2 inches in width which at 45-degress should only narrow down the fire pit opening by a total of 1.5-2 inches.
I was surprised his incinerator hasn't produced any visible smoke at all and I just thought that those features might have helped.
what size was the holes on the bottom . you said 1/2 inch at top but I did not hear what size was at the bottom.
I like the fact that he didn't edit out the mistakes he made and what didn't work in order to demonstrate how the various changes effect the outcomes. Great video!
Absolutely that way if the next person thinks that what he did is the best way they can see that it's not and it'll save them time and headaches. They say that failures are steps toward success.
Why wouldn't he... you people were paying him to experiment... it cost him nothing and he probably made thousands above what it cost him... not to mention he had a sponsor paying him...
@@t.c.2776 I suppose for the same reason 9/10 youtubers edit out any flubs, mistakes, bloopers, mishaps, and anything else that may not project a polished and professional appearance to their audience.
He did build a bigger fire at the end to get more heat into the system. Did it have less smoke when it was a smaller fire with the dry wood?
😊y❤@@SmokinOakd❤h😢😅😅
I appreciate you doing all of the homework and expenses. Saving me time and money. I'm a single dad, and I enjoy doing little things like this with my daughter to show her love. Burning firewood and hugging my little one is so great. Every dollar counts, so thanks again.
My daughter has also been quite enamoured with our fires we build together. She has expressed an interest in doing some branding. Next weekend we will try just a small quick one on her right hip.
I don't get your reply. If you're being funny, I don't find it humorous.
@@a.m.2339 I'm on the 3rd brand...
@@a.m.2339 That's a great way to teach her that branding and burning skin, HURTS! So don't do it to your animals folks. 😂
Easier to show love for your kids AND your family by not having kids in the first place. Too late to save you but maybe someone else will read this and find some common sense for once in their lives.
Just had to say one of the best integration of a sponsor and not taking the whole frame of the video and giving us continued progress of the project at the same time! 👏👏👏
THIS! I appreciated that you didn't take a break or tack the ad on at the end. And honestly, that meant I heard the entire ad. When I see ads on other videos I just move on or fast forward.
Absolutely
“Build a man a fire, and he'll be warm for a day. Set a man on fire, and he'll be warm for the rest of his life.” -- Terry Pratchett, from Jingo.
This is so deep. I'm in tears of virtue
I loved to read terry pratchetts books for years. May he rest in peace
Lol
I actually loled 😂
I thought if you set a man on fire, for sure he would die. 😆
I'm thinking the only thing you could have done that would improve the performance of your fire pit is more depth. The Solo stoves are much smaller in diameter than your fire pit and they are taller in height. That gives much more space for the air to really heat up as it rises from the bottom to the top of the air channel. Great video! I know I learned a lot by watching it.
thanks! definitely would be better taller
A taller, narrower pit also concentrates the heat more. You want maximum heat and oxygen to maximize combustion.
@@Fixthisbuildthat As a mason if you didnt get the fire clay or at least fire mortar that quick set is going to crack with higher heats
Yes, and the fire needs to be big enough to really heat the wall of the fire pit.
This makes it so the air gets proper flow and is superheated so it really combusts the smoke.
I own a solo stove and it works really great, as long as you keep it properly fed.
When it's really hot it burns green wood mixed in without any smoke.
@@Fixthisbuildthat or deeper. It doesn't have to be taller 💁♂️
Came for the DIY ideas, stayed for the experimenting! It was so entertaining to watch all of the thought process going behind it
0:27 fun fact! (Assuming you don't say it later) the reason smoke seems to always be blowing into your face is because of convection. With nothing obstructing the air's movement toward the fire(and no wind) the smoke will rise straight up. BUT! since there is often a person or group of people somewhat clumped together around the fire, the air that would come from behind them is slowed meaning the air on the other side of the fire that isn't slowed will assert more force bending the convection current and thus the smoke towards the people blocking the air. Of course with the wind blowing the smoke will follow the wind but still be affect by the convection
Came here to say just this.
Comments like these are why I always peruse the comments section of videos. 10/10 solid fun fact.
This is why I often add a large, flat vertical stone on the far side of a campfile fire. However it doesn't aways work, because smoke following people is based on the universal law of attraction... whatever you fear will come :)
Physics 👍👍💯
Yes was going to say this. The reason it seems like the smoke follows you is because it does. For the reason you mentioned
Really liked your pit design. There is another way to have a less smokey fire. You don't construct a tipi. Instead you pack in tightly the logs at the bottom. You add smaller pieces and at the top you construct the twig, pinecone, dried orange peel pile. One lights the top, not the bottom. The fire burns gradually downwards but having the fire at the top means it burns the gases coming out of the gradually heated logs. Much less smoke and significantly more heat.
that sounds like a cool idea, definitely going to try that!
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Known as the Council fire. Boy Scout style. Works great.
Interesting! Can you build your fire this same way in an indoor fireplace? Less smoke and more heat is good there too.
Yes
The amount of work, time and investigation you went through to figure out how to exactly create the closest thing to a smokeless fire pit was pretty impressive to me. You went beyond my expectations and I appreciate the days it took to film this and do all the drilling, experiments & etc. I’m subscribing for more of your videos. Your thoroughness in figuring out the perfect method will save me so much time and error.
Tip for calculating the airflow: Measure your 4 gaps in the bricks. That's the surface area of the inflow. Ideally the outflow should be similar in size to the inflow, or slightly larger. Number of holes * pi * diameter is the surface area of the exhaust. Compare the two numbers and then adjust the hole size (or number of holes) until the inflow area matches the outflow.
Would you want the airflow to be the same between the top and bottom? Would it not eventually choke the fire if the bottom weren't receiving more air to feed it? Or would the heat of the fire just naturally pull in more air from the bottom regardless; provided the holes weren't smaller and/or less numerous than the top holes.
Surface area of the exhaust = (number of holes) ⋅ π (diameter / 2)²
(Number of holes) ⋅ π ⋅ diameter would give you the total circumference of all of the holes, not the total area.
@@flennboyd6413Probably Automotive Engineering or Furnace tech/engineer. There's a big world out there man, lots of really cool things that people do.
@@flennboyd6413 pyromaniac! 😂
@@Philitron128 probs not as his math ain't right tho. There's also thermal expansion to consider if the air is heating up
There is one detail about fire pits that people keep forgetting.
If the fuel (firewood) is higher than the secondary holes, the secondary burn will become a primary burn for said wood and thus produce smoke.
If you want to keep your current system then do not build the fire higher than the secondary holes (maybe an inch shorter).
If you are going to mod the system, add a 4th layer of stones and keep the firewood below the holes.
So stack four high
Yes, very true. Still worked very well despite, but yeah, that would improve it even more
Also, he should put some pipes or whatever for the air to have access to the center of the flame, not just its outside.
Stack 4 high
Mortor mud it
Fire hole metal
.5 inch hole every 1.5 predrill the center
Punch
2 inches of gravel
Pavers
Wow! I have zero intentions of doing this to my fire pit. I don’t even know how this video found me. But, I certainly appreciate the amount of time, money, and work you put into this video. You’ve earned a like. Great job 👏
@Hello there, how are you doing this blessed day?
I agree with everything @scottvriethoff6633 said. My hats off to you FIX THIS BUILD THAT for all the labor and money you put into this test for others to benefit.
This guy is brilliant! How beautifully he explained the various tests he conducted! He was so determined to achieve the objective of building a smokeless fire pit, and he finally met the objective!
Great video. But having owned several Solo Stoves, the most important factor in the intensity of smoke is the dryness of the wood.
That, and the speed/direction of the WIND...This doesn't work...
Actually the solution is a three quarter size burn barrel, with a lid ( that opens) and a pipe that has a flue… perfectly distributed heat, no smoke whatsoever .much better heat source ..use it in backyard for gatherings and at hunt camps
@@brentfarvors192 its too wide to properly work, the air needs to get hotter so it will rise above the smoke, taller narrower versions do actually work to some degree
Meh... do a search for 'dakota fire hole' or 'dakota fire pit'. I've been building low-smoke fires most of my adult life without anything special. You just have to watch the wind direction. Air feed is the key along with a hot fire.
I think the next step in efficiency would be to add spiraling channels around the outside so that the air in the walls of the fire pit can't just go straight up, but has to go at like a 45 degree angle around the outside, increasing the time it spends in the wall and therefore the time it spends heating up. This would likely result in a secondary burn happening sooner after starting the fire, and a more complete secondary burn due to potentially increased velocity.
Another feature to help secondary burn might be to add a lip above the top holes, as is seen on the retail fire pit design he's imitating. This would force the air exiting the top holes towards the fire a bit before it can rise above the firepit, along with adding some radiative insulation to that region to help keep temps up and maintain the secondary burn
Brad, your relentlessness toward seeing a job through to the and and your relentlessness in maintaining a great attitude is one of the most inspiring things about you and this channel. It is easy to see it is not a show for the video - it is authentically you. Thank you for all you do and the videos you make - this is truly one of my favorite channels in the maker space. Keep up the great work man!
thank you, Adam. Appreciate the support!
Took the words out of my mouth. The effort you put in to this is amazing. Great video!
@@Fixthisbuildthat
Hey Brad, I’m totally high jacking this comment just to ask you a question.
In one of your videos I heard you live in the Nashville area. If this is correct, I was wondering if you could help me out. I’m wanting to build a “big girl bed” for my soon to be 3 year old daughter. I don’t have a workshop and am looking for an easy way to build this twin bed. Reply back and let me know if there’s a possibility you could help.
What you tried to build is a gasifier stove. However, that design relies on two things: small enough diameter to heat up the walls, making the secondary air rise up by draft, and small enough diameter to deliver that air into the flames. It's not really well suited for a large but flat firepit, but kinda works if you make the fire crazy big, as seen.
I'd argue that one thing the pit would benefit from would be for the bottom airflow to come out from _under the logs._ In the current iteration, it just tries to get to the flames from the sides, which is better than trying to enter from the top, but you still get convection pushing most of it upwards, rather than allowing it to get near the actual fuel and thereby replenishing the oxygen levels more effectively.
Yeah, I was just writing about diameter/height ratio - and drainage: seems likely to collect water when it rains, and moss and a little ecosystem! The DIY double skin drum I saw on here before I saw the solo stove advertising everywhere - that had legs built from the base of the drum.
Rocket stoves have built in thermal mass and, like, hardcore substance - as do pizza ovens. Which is kinda what you want in a garden feature. Even though the solo stove looks very futuristic, it's not everyone's vibe and it probably dents and tarnishes as much anything else. And a drum is already a relaxed & utilitarian DIY vibe. Not pretty.
Nice! We can’t wait to see your video🎉
I came to the same conclusion with no knowledge about fire pits, and only the information he provided.
This is what I came down here to say. In fact, everyone seems to be saying the same thing
Loved this, I have a Solo fire and it does smoke to begin with even with dry logs. You also get a better secondary burn with a full fire across the width (rather than a tall fire) as the air passing along the side to come up through the holes is heated more... Great job!
One suggestion I would make to reduce smoke, indoors or out, is to build an "upside down" fire. Put the biggest pieces on the grate, on the bottom, then the next smaller, at a right angle to the biggest ones. Keep alternating layers, leaving some space between the pieces for air, then put newspaper and small kindling on TOP, NOT on the bottom. You may have to feed a bit more small kindling at first, but not for long. You will be amazed at how much cleaner, quicker and hotter the "upside down" fire will burn. Each layer heats the layer below as the fire goes DOWN (trust me, it will, even though fire generally does go up), so each successive layer burns readily, and there is hardly any smoke. When you make a fire the usual way, the bigger wood on top isn't hot or dry enough, so there is quite a bit of smoke until the big pieces get going. Once the "upside down" fire gets down to the bottom layer, you just feed it more wood on top as usual. If you try this method once, you'll never go back.
I'm going to try this out. Burned my first fire of the season tonight.
I agree, this man knows what he is talking about
We always do the stacked cabin type fire with the newspaper or kindling underneath the “roof”. I’m going to try this way next. I’ve actually never heard of it before.
In most cases this will not work. Heat rises. Ashes smother flame. If you need to get a fire going use log cabin or teepee style. Some genius taught this method to our kids for 'winter survival'. Apparently cold branches won't burn this way. Everyone had to eat cold weinies.😥🍖🥶
@@blairzettl3933 Upside down is THE way if you have a wood stove/fireplace, not so much an outdoor fire.
I love when there are smart knowledgeable comments, thanks everyone I am getting my degree in life from y’all!
My metal chimnea just rusted out and we were talking about putting a fire pit in. I just ran across this video. Thank you for figuring this all out for me!😄. I’m going to talk to my family tonight about building one just like yours. I promise to tell them it was you that figured it all out!😄😄! Thanks again!
Dang dude, you put so much work into this video. Thanks for satisfying everyone’s curiosity
EXTREMELY THOROUGH!!!!!!!
I really appreciate the “I’m not going to give up no matter how long it takes” attitude in this video.😂
Oh my gosh! I just figured out my love language is smokeless fire! Thanks so much for your attention to detail and showing your process, can't wait to try this on my fire pit that came with my house!
Great video! I liked it!
Here's what you missed when you looked at the patent for the solo stove. The secret of why it generates almost no smoke isn't to do with the size or number of holes in the top/bottom. That is a factor though. The biggest factor is to look at the ratio of the height of the pit to the circumference. Basically, the solo stove is skinnier and taller. With a pit of this diameter, you'd have better performance by building the height of the pit upwards.
This increases the effective space of that insulating layer, providing more area for smoke and gasses to slow, cool, get trapped.
Or you can use an old washer tub....
I agree. Also he should taper the top a bit too
Also, the solo stove has holes under the burn area too.
I'm usually not huge fan of these videos but you by far have a great presentation that would actually help people that have very little experience making things. If want I'd give few simple ideas to maybe make that an easier set up work better or you might take the things I do make them better. I just been working way to many hours and really just learning the video stuff
Fun video. I like how you showed the basics for the build but cut out the fluff yet still showing each of the different tests without just cutting to the finished result. Excellent!
... you have a fire in front of you. Why use a lighter😂
He probably read the instructions.
He would have melted/fried the tape on the end of the stick and dropped the smoker in the fire ya bozo. 😂
Came to ask this aswell..
BRUH!
I was thinking the same 😂thing
nah he could have just held it far enough way @28th_St_Air
Great video. It would have been good to see the unmodified original version with the same dry wood you used at the end. As I feel like that's what actually made the difference
It was a good video and I learned some ideas, but iam also thinking the dry wood is what the key factor was !
Yes, correct me if I'm wrong, but nothing seemed to work until the fuel type and amount changed. So the conclusion should be: don't change the pit, just dry the wood and add more.
I like the attempt to engineer the pit though, and I'll probably do something similar because it's cool :)
I dont even have a fire pit but this video was suggested to me. I loved your energy and it was perfect editing, i love how you integrated the sponsor in the video while showing you drilling the holes and not making it just a seperate segment
I have a different brand than Solo and it is completely amazing. Really cool almost welding type flames coming out of the sides at the inner top and bottom. Some smoke but only on super wet stuff (I've burned mulch). I have 3 problems with the setup. 1) They are all very tall so its not really a firepit feel. 2) they are completely closed in except at the very top so heat is focused basically completely up. So they are not as warm either. 3) wood burns really well and super hot so it also burns fast.
It's all very impressive physics and thermodynamics but it does not feel like a campfire pit type thing. Feels very "efficient factory produced fire that can melt metal." haha great video!
Good observations. I wonder if it would help to suspend a flat plate above the fire? Theoretically that should redirect the hot air toward the outside of the firepit.
I expect that the fire will eventually destroy the plate unless it’s made of ceramic or fire brick or something. And I wonder if a cone sticking out of the middle of the plate might encourage more even distribution of the hot air than only the flat plate.
Seems like there should be a way to get the benefit of the efficient, smokeless fire without losing out on the warm, comfy firepit.
What brand?
So what brand do you have so I can check it out?
Hi-Flame Bonfire Stove fire pit. 20.5 inches
This is a really fun experiment! I enjoyed your explanations for why you were doing each step and that tape trick for the drilling stage is a keeper!
You are amazing. So much integrity. You didnt edit out the hard work and mistakes and you listed your references! So many tubers dont do that. Anyway, the results are there, Id like mine to be even wider and more shallow. I might just sacrifice some smoke - maybe. TY
the smoke is always in your face because the smoke will travel towards the tallest things around the pit. Think of it as smoke traveling up a wall. At one end of my pit I have a tall rock (almost 4ft at the peak) I am not sure the science behind it but this makes the smoke always migrate towards it and then up the rock and up. Just something to think about. great build as usual.
Air rises over the fire, pulling outside air towards it. You block that inflow, so rather than it flowing in to the fire it can get pushed out towards you
Yeah, flue effect sucks the air through air speed differential.
No your body acts like an air dam. It blocks air from getting to the fire . What creates a vacuum and the fire smoke moves towards you. The more people that sit around you the bigger the vacuum. So sit alone and the smoke will not bother you.
I would hang a lantern there. lol
Yes, the stacking of the wood has more of an influence on the smoke compared to the fire pit's design. What works for me is stacking the wood to create a closed high temperature chamber, like a furnace, with smallish entrance holes for the air, and corresponding exit homes for the smoke.
I agree
Great video. However, the part that's missing is the ratio of stove height to diameter. There a powerful convective element with this process you just aren't going to get with such a wide and shallow fire-pit. The point is to increase the secondary burn which takes place at the top of the fire. In your stove the top of the fire (flames and smoke) is already outside of the fire-pit. It's just NEVER going to work like that. You pit needs to be 2 or 3 times higher for that diameter. Notice on the patent how the top is tigher than the rest of the pit and the ratio of heigh-to-width. The secondary combustion has to take place BELOW the top surface of the stove. Dry wood for the final tests but wet wood for the preliminary is also quite misleading. A lot of people will fail following this advice.
You brought up a point that I was thinking. The idea that he is copying does have a higher ratio, meaning the fire pit should be taller. Everything else about this is good and I think I'll build one of these.
correct to get the chimney effect
At first I was ready to rip out my stainless steel insert on my garden BBQ (we don't call it a fire pit) and spend a Saturday in May drilling 2500 holes...thanks to this post I'll save the effort...title of the video should be wet wood is great for smoking
Super fun project, Brad - had me glued to the screen start to finish! I hadn’t really heard of smokeless fire pits unless they were propane or gas fed so that was pretty rad. Great video!
Thanks, Nils! It was a fun one to try
Wont even bother watching this BS; It doesn't work...
@@brentfarvors192 Did you try? What's your experience? I'd like to learn.
@@Dgiztred Yes. My "experience" is exactly as posted; The ONLY WAY to control the quantity of smoke, is to burn on a clear (high pressure), windless day, using the driest and most finely cut fuel available...Using the method posted here will make the fire burn HOTTER (More air flow= A hotter flame), but will do NOTHING for the smoke; Especially when starting the fire, and when it starts to burn out...I've tried with Pits/Barrels, and everything in between; You aren't going to beat physics...
For that design, smaller fires will be more prone to smoke. That's why the large fire worked better. The fire has to be large / hot enough to heat the air in the gap so that it's primed for secondary combustion when it reaches the holes at the top. For that you either need a hot fire, or taller walls to allow my travel time which equals more heat.
yeah I'm looking at that manufactured one and I'm thinking, just taller walls
I rarely get heavy smoke with any pit, but it’s because of box fire in conjunction with tee pee style. It creates it own vacuum the hotter the fire the faster it’s heat is ejected along with its smoke. Needless to say, I like raging fires. Fill my truck bed once every two months with good dry wood.
When wood gets hot enough in a low oxygen environment, it produces wood gas, which is flammable. Combustion needs oxygen, so you see fire "shooting out" of the vents, which is actually the boundry of wood gas and oxygen mixing and burning. Gas burners have this same boundry flame, but inverted, with a stream of flammable gas into an area of oxygen.
Fun fact, the fire we see is mostly comprised of incandescent soot, material that gets so hot it glows like a lightbulb or forge metal.
wood gas...I like that 👍
So it's true that wood doesn't burn. It gets hot and produces flammable gas. If you look very close to wood burning there is a slight gap between the wood and the flame.
Correct, if you're seeing flames out of the top holes, it has to be wood gas being drawn into the lower holes, & mixing with the air to then be ignited as it exits, looking like the burner you talked about. Just air coming out wouldn't really do anything... My woodstove has secondary burning, but the flue comes outta the middle of the firebox (damper can be slid open to load wood, so it exits the stove by flue not door, lol)
If you notice on the Solostove the top opening is necked down smaller than the diameter of the main burn chamber. That increases the velocity of the air leaving the chamber and this increased velocity produces a slight vacuum in the chamber. The vacuum pulls more air through the secondary combustion holes making a more efficient second burn and less smoke.
I don't even know how this video popped up but I had to watch it all. I do not even remember what my initial search was, but it had nothing to do with firepits. But now i want one again. Great effort! Relentless! 👏
I have made similar fire pit from the laundry inner tub, which has tons of holes. It works great with no smoke. It seems like in your experiment, the fire pit is too low so it doesn't allow much of the air flow. The upper holes should be at bit higher. Thank you for the experiment and share!
I have 3 of them, every one is surprised they do not smoke. I also use dry wood, which makes a big difference.
I think the only factor here is using dry wood. 🤔
@@bam5732 - They both play a role....Even with the driest wood, you'll still get lots of smoke if the fire doesn't have an ample oxygen supply. Likewise, even with the best possible air supply in the word, if the wood is wet it's gonna smoke. It would have been nice though if he'd actually shown the old pit with dry wood.
Laundry tubs are great. I believe they can also be stainless steel.
@@scottcates most of the time they are stainless steel, or at least the older ones are. Also, the older ones are driven by a big pulley, which can be left in place and serve as a stand. :)
I love the excitement and genuine pursuit in the experimentation! I learned something to improve my fire pit and enjoyed the presentation. Thank you!
dude tried it with a wet wood, did bunch of improvements that didn't help. Eventually he added dry wood and omg - it didn't emit as much smoke as it used to. Definitely a good design :D
It would be interesting to have done a control burn using dry wood before drilling the fire ring holes. This would show how much of the improvement in smoke reduction was due to the modification of the fire ring and how much was due to the drier wood.
Great video otherwise. Very easy to understand. Will use your tactics when I build my next fire pit.
What is most important is to keep the wood consistent (the same wood) from burn to burn in order to make the best comparison.
I agree cuz I was like so just use dry wood then?
Pretty sure it would be exponentially better if you placed a another layer of stones on top of the steel liner to add as a "ledge" so that the top opening is a little tapered.
Hm probably true, just like the solo stove
He’s onto something here. By narrowing the top of the fire pit, you will achieve what is known as the Bernoulli effect. A greater force of air thrusting through the whole system, and theoretically more fweefwee
@@CharlesThomas-xv2yn - Yes i can answer, but please, stop calling me "in more detail"
:oP
There you go, DRY WOOD MAKES ALL THE DIFFERENCE! problem solved
After doing this project years ago, what I learned was it's easier to get the smokeless results with a smaller firepit ring. I think this is because in order to get smokeless results you need higher temperatures which is easier to get with smaller pits, unless you plan on burning A LOT of wood at one time. This is probably why the solos aren't that big.
If you ever decide to return to this project, you could place a small lip around the top of the internal circumference of the pit forcing the air for the secondary combustion in rather than straight up as it exits the holes while simultaneously trapping some smoke underneath the lip which may increase the combustion but also possibly reduce the airflow. I am curious to see the effect. It's a similar approach the reducing the diameter of the pit without making it look like a soda can.
Thanks for making this. I used your first video to build my firepit recently and it's producing way too much smoke so will definitely be giving this a go!
Don't know where I'd be without UA-cam tutorials. I appreciate the time spent teaching us this
Great video and tests! Love the tape idea for drilling, I'll remember that.
For my outdoor fireplace, I added a 12V 4" boat bilge blower underground, contained in drain pipe that draws air in from about 8 feet away and exits under the center of the pit.
When I need to get the fire going quick, or reduce smoke, I turn that on (hooked up to a 120V to 12V adapter and a smartplug) with my phone app and boom...raging fire and no more smoke!
I'd like to see a video on that! I've thought about doing something like it for my fire pit. How do you keep water out of the air duct? What did you use for the duct to keep it from decaying from the heat?
You will eat a LOT of wood that way. Just make pit smaller so coals air mor in contact and heat that metal more. As I posted above 450F is minimum to get secondary burn.
The information you share when you make mistakes along the way and work through them is 100% the most valuable part of this video :D
Brad, the best part was you used the lighter, when the fire was already going. I love it man. Seriously. it shows we're purpose driven humans...I have a need..I have a tool..I'll use the tool. Haha
Nice video!
Aside from comparing wet wood "before" to dry wood "after", this is not a bad video.
Keep building awesome stuff :)
Exactly.The real demonstration here was on the importance of burning properly dried wood.
Probably could've saved 6 hours of work by switching to dry wood.
I burned very old and dry oak flooring last night in an open pit and it was smokeless.
I hope you've gone over why smoke burning is an important way to help alleviate bad air in heavily wood burning communities, too. Great vid!
I've watched all of these hoping that someone will get to where they "somewhat" match the commercial available ones. This is getting it a step closer! I think, and I could be way off, that possibly these DIY self attempts are not matching the height/width ratio of the commercial ones. Being so much wider, I wonder if the air going up the sidewalls doesn't have enough time to heat up. You need a much "wider" fire to heat the sides, and the air traveling up the sides is so short. *** BIG CREDIT goes out to all those trying.
yes, 100%. I don't think I'll ever get the consistent secondary flames on this design because it's so short. The air doesn't have enough time to get superheated consistently. A taller smaller version would be much better to achieve that
Next project - bury a smokeless barrel system!
@@Fixthisbuildthat I don’t think your fire pit is too short. It’s too wide. Over the years my family has owned a solo stove and two breeo fire pits. We’ve learned that smaller diameter fire pits make it easier to produce a smokeless fire, and they consume way less wood.
Consider fabricating a wider top ring that reduces the inside diameter of the opening and covers the upper vent holes, protecting them from wind
Lastly, spreading coals closer to the walls and adding logs to the perimeter reduces excessive smoke much faster than keeping your fire centered
Great work! This is one of the best DIY smokeless fire videos I’ve seen
I think that having the same air source for the primary and the secondary burn is an additional 'mistake." You want the secondary burn air to heat up and exit the top holes with pressure. Having the primary air come from the same flow reduces that pressure. Notice how the patent separates the airflow much more distinctly.
Everyone saying it needs to be taller or skinnier is alluding to the fact that there is an optimal way to make this fire most efficient AKA not have any smoke. You are right, but the patent exists for a reason, there is much more thought/calculations and actual enhineering going on behind the scenes that would take more than just winging it with random materials. There is a lot of thermodynamics and heat transfer going on here that isnt as simple as “just make it tall and skinny” because there is obviously a sweet spot on both those constraints.
Or, more likely, your original fire was simply too small for the size (and wetness) of the wood you were using. You'll note that in the 'after', the fire is substantially larger than the 'before'.
Dude I've seen so many DIY videos and they're all good, but you had me so thoroughly engaged. I was locked in each step and was so eager to see the successful outcome. Great video.
The way you took a scientific approach was great and the colored smoke bombs were a brilliant. Nice work as always. This had to take about a week of experimenting to do all that and I appreciate that.
I really liked your video, I've watched many and this video was the best. I loved how you actually tested the different size holes until you got what you were shooting for. I've got a similar situation and wondering what size the bottom holes are and how far down from the top are the 1/2" holes and how far up from the bottom are those holes? Thanks!
Randomly searched a video about making a smokeless firepit, got the added benefit of a UT shoutout. Go Vols indeed!
A great video. I do love your experimental approach and showing things step by step. Very instructive and yet enjoyable.
Glad you enjoyed it!
Seeing how the air travels by using the smoke pellets was cool to see and helpful to see what size hole works best. I’m making a smokeless pit right now and this was very helpful. Thanks!
Wd is awesome and multi purpose. My grandfather used it for his knee pain from arthritis before going for walks.
Try arranging your logs into a lincoln log cabin style. lay 2 wood splits parallel to each other and then stack 2 more splits parallel but perpendicular to the bottom splits. like a tic tac toe cross. helps promote airflow! I use that technique when i smoke meat! Great vid Brad!
That's what I started with originally. The teepee definitely smoked less on start up though.
@@Fixthisbuildthat really?? Dang. Ok ill shut up haha
So if I'm getting this right, the biggest factor is use dry wood!
That and getting it large enough to cause secondary combustion. Big fires burn hotter. I have a 24 inch Breeo and am astonished by the amount of wood it burns through. I can't imagine the 30 inch version!
I think the geometry of the fire pit may have a lot to do with it. Smaller diameter and/or taller pit. You want the steel wall closer to the fire to transfer more heat into the incoming air. Taller wall gives the air longer to get hot on its way up and out.
This is what I was thinking the whole time. His fire pit is way too wide and shallow for this application, and using extra dry wood for the final test means his before/after doesn't mean much. If you build a super hot fire with super dry wood you're not going to have much smoke, it has nothing to do with the "smokeless" pit.
Its definitely the geometry of the pit. The way the solo stove works is that the upper air vents provide fresh oxygen to hot, combustible fuel and burns off any solids. With the current diameter of his pit there is too much room for a heat gradient to form, this causes the upper air vents to pool cool air into a region of cool air and smoke.
I came here only to look for someone that has noticed the wide diameter of the fire pit. Definitely, an underrated perspective looking at the rest of the comments.
My thoughts exactly!
Thumbs Up! Not only for the information provided, but mostly for the incredible amount of work required for a 16-minute video.
It's heating the air that's injected at the top that stops the smoke. The hot air hits the smoke and combusts. Same system as "clean-burn" log burners. I think you struggled a bit until you put tons of wood in due to the size of the metal ring. A small one heats up faster and gives more heat to the air being pulled in.
We did something very similar by leaving bricks out of the bottom layer around the outer ring to create air gaps, and then I put regular brick [yes I know could've/should've used fire brick] flat on the ground with expanded metal on top of that to ensure constant airflow under the fire.
Also using an old washer drum works really well.
Cool video btw.
When I moved into my new house I wanted a smokeless fire pit. I happened to watch this video. I modeled mine to yours. I used the 1/2" holes on top and bottom, 1'-1/2" apart. I have to tell you, man. My girlfriend and I are very happy with the work we put in! Not only that, I showed some of my carpentry friends, and they want the specs. This was a great build! 👍 also I got them flames out the top holes
the main factor i've noticed when it comes to smokeless fire is temperature. the hotter the fire, the less smoke gets produced. So when you look at the before / after at the end of the video, you can see theres alot more wood in the after, more flame, more heat - less smoke.
Airflow obviously is a huge factor when it comes to fire, and also temp of a fire. im not entirely sure if there are any other factors that go into smokeless fire other than temperature and airflow by extension if i'm honest, but you can get really good smokeless fires just by dumping metric butt tons on wood onto them without much real thought.
Make sure it's dry too lol
Awesome video Brad! I always think of your videos from the perspective of your neighbors and it makes me laugh. “Honey, looks like Brad is lighting the 47th fire of the past 24 hours, let’s see what happens with this one!” 😂
😂 😂 OH yeah, they definitely get a show
I think your Math's off a bit.
In 24 hours we would not have but twelve or so of 'daylight' and fewer of the sort of light seen in the video clips. Lets say, ten hours or 600 minutes MAX.
Allowing for time to load the pit, start each fire and get a respectable burn going would consume not less than ten minutes per instance (in a dream world perhaps), leaving but 130 minutes for the forty-seven video clips or 2.7 minutes per clip.
The first fire and smoke (edited) clip ran a minute twenty plus with several obvious cuts/clips cobbled together along with some quite rapid talking. Let us assume it took significantly longer that 2.7 minutes to film that first clip.
Now, between takes, we need to cool the pit down to remove the ash and such and reassemble things, add combustibles, ignite, etc.
Then there is all the work to perforate the ring - not starting fires then, was he?
Not sure where he lives in TN, but outside of town with a few acres, folks don't pay much attention to their neighbors - esp if they have Cable and Internet and a place to take care of or a job in town.
@@gooeytarballs you must be fun at parties…
@@ImYoutubing247 😂👍
@@ImYoutubing247 29.4% of party guests especially enjoy the first 13.7 minutes of the party. 😁 lol
great instructional video! one key is keeping the fuel lower than the top holes
Smaller solo stoves get a much better secondary combustion. I have one and I've made a tincan version as well. The tincan one worked just as well. So basically what I'm saying is that a smaller fire ring would give a much better secondary combustion. Large holes on the bottom small on the top. What else could have worked even better here would be to put a raised grate lining the bottom to allow more flow through the inner chamber and up through the secondary holes. Great video though, I'm going to build one i think as well soon.
The fire shooting out of the holes is actually the wood gases burning. Honestly, fire ring is too large a diameter, and not tall enough to create those jets...It takes convection to create them, and the larger diameter keeps that from happening consistently around the ring.
Yep, exactly what I found. This is pretty much the best you can do with this style ring. But still way better than stock
I'm thinking the same thing, a taller and/or smaller diameter ring could work better. Either way, nice testing with the fire pit you already built!
Thank You for sharing. I really appreciate your experimentation and exploring and showing me/ us your results. Makes lots of sense. I am planning to add one to my backyard soon and I hadn't even considered the smoke element. Until I came across your post. THANK YOU THANK YOU THANK YOU 😊
I use an old washing machine tub for a fire pit. It's stainless steel and it has a ton of little holes all the way around it. I always get flames shooting inwards through the holes. It's super cool to see.
Make a short clip! It doesn't have to be fancy, just you sharing what your pit looks like. This is my pit..
.and that's it! 🙏
If you want a prtable pit you can use the drum of an old dryer
It has all over the place holes and is really cheap
This is what we use. Works great.
Wow, this is EXACTLY what I was looking for!!! Great video, thanks a bunch!!! Oh, and also, keep the flame going at all times, it helps burn up the smoke!😊
I appreciate the amount of effort you put into this. Makes me want to try this someday!
thanks!
I think a big part of the efficiency of the patented firepit unit is its size. Your fire ring is bigger, meaning there's more air in the middle to heat, the fluid dynamics of the air flowing through the holes may work differently, etc. Compare with the extremely upscaled version where you have a 6' diam fire ring but the same heights, same size holes around the rim, etc. I think their patented unit just has an optimal size ratio for smokeless fires given a particular expected fireplace height.
I think this is true as well. The SOLO stove is smaller in diameter and also taller, forming more of a chute and channeling the heat better
There are flaws with the SOLO design that lead me to not buy one, but I'd like to reverse engineer it some day and build a better fire.
But ultimately, it's almost impossible to build a smokeless fire if you use wet wood. The wood just can't get hot enough.
A lot of time and effort to make this video! A BIG THANK YOU! Had a fire pit at our summer home and always wanted to figure this out. You did it. Great personality!
@Hello there, how are you doing this blessed day?
Wow 🤩, the amount of effort you put into this video making that fire pit is that of the top home improvement professional! I didn’t think I’d enjoy watching this so much. 😂
I need to put more effort into my fire pit now. 😆
Interesting experiment, Brad. Keep in mind that equivalent area of holes doesn't equate to the same flow through them. For example it takes more than four 1/2" holes to equal the flow through a 1" hole. That's the engineer in me coming out now.
Bill
Wow we have a genius among us
@@daveklein2826 No, just a retired engineer.
So, should I drill 1" holes?
Excelente video....muchas gracias
Yikes, there is a lot more science here than I had conceived, but the rewards are great…nothing worse than teary eyes around the camp fire, thank you for showing the way!
Nothing worse than teary eyes around the camp fire? How about if someone fell in the fire?! That's third degree burns, KIRK! Sheesh, you and your first-world problems.
Hats off to you. You did lots of effort to prove your point. 👌🏿
and the point is that dry wood works much better :)
I used a double walled stainless steel washing machine tub to make a fire pit in 2008 and it worked just like this. it was incredible. Wish I'd realized what I created and commercialized it....
Diameter vs. how deep the firepit is, seems to be your main issue.
Also, you could try making a bed of the firering to force the air intake to exit closer to the center of the firepit.
EDIT: DAMNIT, bumboclat was 22 hours earlier than me!
EDIT2: Also, another way of improving would be, assuming you make a firering bed as I suggested, would be for iron rods to entertwine with the middle of the firepit - this would act both as a way to easier set up a fire, but could even be bend into being able to support a stove - as well as absorb a lot of the heat from the fire, and since it being iron and connected to the firering, also heat up the firering quicker, and more, which in turn would make the firering more effective at pulling air to the upper holes.
analyzing stuff and discovering what forces are at play is one thing... balancing those forces to obtain the perfect result is a whole different ballgame.
@@WithmeVerissimusWhostoned You sound like you're being barred from testing this.
I Love the work u did in this vid. I'm in Britain. We use old washing machine drum and fill holes halfway❤
Works a treat
I think the big issue is your secondary air that goes through the top holes is cold. The stones cool the air too much and it is exiting the holes too cold to ignite the smoke. You saw this correct itself when you allowed the fire to burn for a while, which allowed the stones to heat up, and then produce secondary air that was heated. I believe the better solution is the one that is already out there. You need to have two rings and a small insulating air gap around the outer. The air traveling up between the two metal rings is going to be be heated faster and hotter.
Just what I was thinking, all the heat is sucked up by the stone.
I should have started reading from the oldest post to the newest.
In addition to your trial and error on the fire pit, I will add that the "Lincoln Log" stacking of wood is much better than the "teepee" method of stacking with respect to air flow and reduction of smoke.
I have been wanting to make my own fire pit for a while, and I will be sure to follow these plans/ideas when I do someday build mine.
exactly, and I even saw a vid where flat stacking combined with ignition from the top is even better to reduce smoke
I'm inclined to agree. Early Spring of 1996, while playing with my modified Chemlab kit that I had received as a Christmas gift months earlier, an unfortunate reaction occurred and sent flaming liquid down the side of the workbench right on to a pretty elaborate lincoln log fortress that I had created. The blaze only lasted about 3 minutes but the absolute carnage was noteworthy. The lincoln logs created a perfect environment for mass combustion. The workbench and wallpaper were damaged. Carpet ruined and about 70% of the log fortress was unusable afterwards. Several action figures were lost in the fortress(RIP to Snake Eyes, Destro, Baroness, Wolverine and Omega Red).
One of the differences from the patent and your fire pit, is that in the patent, the bottom inlet air is going underneath the fire. Yours is just going to the base of the fire, so anything not near the sides won't get enough oxygen. With a grate that keeps the fire, or most of it, off the bottom of the pit, you'll give the inlet air opportunity to go underneath the fire. That might take care of the small amount of smoke.
Enjoyed the heck out of that video! There’s a surprising amount of engineering in that little fire pit - thank you for posting this - was thinking about doing this over the Christmas break - thanks so much!
Glad you enjoyed it
I think your fire pit is just a bit large for how low it is so you'd need an absolute inferno in there to get the secondary combustion really shooting out flames. You need the height to give the air more time to heat up and to separate the secondary flames from the primary fire
I'm surprised that he didn't understand this concept. It's kinda like watching someone try and copy the design of a car, without understanding how a car actually moves.
You can put four wheels on a frame, and add a pedal. But if you push the pedal, it's not gonna do anything UNLESS you also have a drive train. It might LOOK like a car from the outside, but it's missing the science under the hood.
His design is fine - it's just massively oversized, like you said. He's never gonna get the temperature differential necessary to cause the draft he's going for
@@zp944 Well, air does heat up quite fast tho so it might be easy to overlook. I'm not an expert on any of this so even though I'm kinda confident in what I said I can't really back it up with anything else than 'That's what it looks like to me'
:D
To have a better effect of smoke-free fire pit. The walls and the fire should be close together. The smoke free is due to feeding fresh oxygenated air to the base of the fire, to help with complete combustion.
See a Dakota Fire Pit.
Apart from the diameter issue, the solo stove has a rolled in top lip which shapes airflow. You can approximate this with a cap ring as long as the upper breather holes are set at the right spacing (I suspect it's 1/3 the internal overhang down from the top edge in order to get the right rolling turbulence to achieve good secondary combustion)
I think the cap is what helps guide the top air holes into the heat to combust. With the cap ring off or upside down it won't have the secondary combustion.
Can these be used for cooking/grilling fires or would a traditional fire ring work better?