Robert Murray-Smith only “Masters” of trade can make people understand in a manner which is down to Earth and you are one of those. You humble me Esquire.
I have been looking into rocket mass heaters for barns/ garages, etc. for a few years now. I was shocked to see one in a house in a very cold environment where they did indeed melt the pipe used for the fire part, and had to re-line it with firebricks. Wow, definitely stupendously hot! There is also a video on here of heating a greenhouse with a form of mass heater and heating water as well, running copper pipes through the mass...the possibilities are very interesting. The idea of making stunning insulation from sugar is wild. Thanks for always bringing new ideas and ways to go about generating power, you always have interesting ideas.
I've had a bucket rocket stove for about a decade now, in the van for camping use. It's basically a steel bucket with a hole cut near the bottom. I stick a couple of large tin cans inside, cut to shape and taped together in an L shape, then fill between the cans and the bucket with some thermal mass. Latest incarnation is 50:50 plaster of Paris and sand. Now it runs hot as a forge, and stores heat like a sand battery. Trouble is, it's heavy as hell. I have a cast iron Dutch oven full of sand that I put on top of it, run it outside on sticks, then use it to heat the hallway of this old sandstone building I live in, up in the Scottish Highlands.
I recall making toffee in my youth - several spoiled pans with an impenetrable carbon foam. It did not take long for my attention to wander and this was pre-smoke alarms so I am guessing 30 minutes on high should do it! The smoke was quite impressive.
Great series, so with a J style rocket stove with the combustion section replaced with a ceramic chamber, a water heat extractor in the exhaust and a heat pump to remove any residual waste heat, I should be able to provide the whole street with hot water and remove the need for gas heating this winter. Just need to organise the kids to feed in the twigs 24/7. If only we could solve the energy crisis so easily.. but maybe in the next video 😅👌👍
Rob you truly are awesome. Carbon foam is the best but very expensive so I made my own from a research paper. There will be a statue of you some day mate.
What you said is true but insulating the outside of the burn chamber and riser tube will keep the heat in as it's supposed to but at the same time cause the steel to get to a temperature that will burn itself out relatively quickly. You do gain efficiency when insulating the burn and riser tubes but the insulation must be on the inside so the steel remains at a low enough temperature to not burn itself out.
I suppose the marketing trick of carbon foam it that its the best insulator material. The best insulator is vacuum because heat literally cant move through it but I guess thats not really a material lol That sugar recipe is amazing, I'll have to try that, thanks! I've been interested in carbon foam insulation for a while after i learned you can basically take a cookie and hold in in the palm of your hand and point a blowtorch at it and hold it there for a shockingly long period of time before you start to feel the heat through the cookie as it actively produces an ablative carbon foam which effectively dissipates the heat
Oh Cool. I saw someone, honey do carpenter here on yt I think, made a rocket stove out of aircrete inundated with water glass, so it was refractory, very insulative, and lightweight. He cast the mix inside a metal frame, for durability. It seems like you could do the stove out of just slip together Chimney pipe with that method. Might also be a good option for people to try.
@@bigoldgrizzly Lime can't really handle higher temperatures. It'll turn back to quicklime pretty quick. At least the bits that are in the biggest heat. Might not matter if the stuff on the outside holds it in. Just don't get it wet! ;)
@@SundogbuildersNet True, the lime filler/binder will breakdown to dust at 875 -900 deg C. I have used it contained between structures such as brick and pipes, where the physical strength of the insulation is of little importance. All firepots will degrade with time be they made of cob, vermiculate/clay binder fire bricks or steel. They have to put up with a lot of grief from oxidation and decarburisation of steels and the repeated expansion/contraction cycles, not to mention overexuberant use of pokers or ash rakes. Behind the tough 'working face' the insulation suffers less from these issues and in some cases can be recycled after the inevitable periodic stripdowns. Unless the firepot is to be built in expensive bespoke specialist cast porcelain type ceramic materials that can cope with temperatures of 1000 - 1400degC, it seems a bit pointless trying to get rocket stoves to run this hot. Better perhaps to accept running at lower temperatures and building with firebrick faces in the firepot and a vermucultie with binder encasing the whole. This makes for a structure which is easy to take down and rebuild..... got a bit off piste there .... and a little carried away....... ;
Not bad in general, but neat carbon foam has a great disadvantage: it burns! To prevent this you can mix the sugar with fine quarz-powder, e.g. microsilica, before carbonizing the whole stuff. That leads to SiC wich forms in fire a thin layer of SiO2 on the surface, shutting off the oxygen from the carbon and prevents it from burning.
Wouldn't be adding water-glass be more advantageous? As that is already liquid and water soluble, but it would definitely be a fine idea! Also borax or a phosphate salt could do the trick.
Brilliant as always. I can imagine this mess being poured over a mold and mold it to the shape you want. Which I am going to try, BTW....as soon as I figure out where to buy Nitric Acid and what it is and how to use it in a sentence.
best DIY, non combustable/stable insulating refractory I found for "usual" high temps is aluminium oxide (blasting grit), pearlite/vermiculite, with sodium silicate used as a binder... works fine for a charcoal fired aluminum melting furnace. Though it did melt before the steel did when I experimented using it as a liner for an arc welder powered carbon arc furnace/crucible , in the hope of being able to melt a handful of steel nails, and maybe cast the metal. (i guess it might turn into cast iron due to carbon from the rods) . Under same conditions a starlight type mixture expanded into carbon foam, and worked fine until it was glowing white hot, and then ignited due to air getting in through the holes in refractory body from prior experiments with gas heating. steel nails had clearly started to melt, as they had started to weld themselves together.
Can you cast and fire the carbon foam in situ around the lower section of the stove, lower the stove itself into an appropriate container with the sugar solution, and fire it up for the two days? Maybe instead of while it is a fluid you could pour the sugar solution, when it has thickened, to a plaster consistency?
I figured out an easier, faster, and more efficient way to use vacuum insulation for these. Take large, wide mouth mason type jars. Use something like a Pump N Seal system (fairly inexpensive) to pull a vacuum on it. Since that uses little tabs to seal, you'll have to use copper or aluminum tape to better/more long term seal it. Then the entire top is going to be sealed with Water glass. After the jar is sealed with Water glass, then you connect various jars with a combo of water glass and fiberglass cloth. After you get the sides of the structure made, mix some clay with fumed silica and/or perlite and coat at least the inside and top of the structure with a thinnish layer of the clay mix. Make sure the top of the jars have a thicker layer to protect the lids etc from too much heat. You're on your own as far as the ceiling etc but also use insulation. Since 32oz mason jars are a few inches wide, along with the 28" or so Hg of vacuum pulled in same, this will provide just a ridiculous degree of thermal insulation, and I mean *ridiculous.* Talking something like R150 in the center, plus the little bit that the insulated clay mix adds to the system.
Robert, have you experimented with Aircrete or aerated concrete as it's known? It's basically Portland cement or other concrete mix including quickcrete that you add whipped dish soap/water mix in place of water you normally add. The trick is to mix soap and water into shaving cream consistency. Why I'm bringing up is because it's like formable asbestos and it's very insulative, it's also lightweight and even floats. You can cut it with a saw, drill it, screw into it and it's amazing stuff as you would say. A 1/2" layer will protect an item from the heat of a blowtorch. Anyway, awesome videos, I never miss them and learn a ton from you.
I've heard this stuff called 'foamed concrete ' and was used on parts of the Canary Wharf project, London UK as it was do light. I'd imagine it would work great as insulation and or fire protection
Have you tried air crete. Much easier to make in big quantities. Also amazing insulative properties and if you also put waterglass on it, it becomes super strong and can even withstand the flowing hot air. That is the/a way to go ! :-) cheers !
Your knowledge base is absolutely incredible! You can make: Diodes (No one else online knows how to make diodes w/o expensive equipment) Carbon foam (is this Starlite?) 🪙🏝🏆Unlocked! ●First pick to have to survive on an island with. If that's an award, you've won.
And there was me using doorsteps of white bread, sticking them in an old biscuit-tin along with some sawdust (to fill any remaining space) and a few holes in the top and bunging it onto a bonfire! It works, but not very tidy, and no-doubt very impure.
Yes, I would go for bread too. This paper (below) claims it has compressive strength of 3.6 MPa with a density of just 0.29 g/cm3 Yuan, Ye, et al. "Multifunctional stiff carbon foam derived from bread." ACS applied materials & interfaces 8.26 (2016): 16852-16861. This time around, I must remember to take the battery out of every smoke alarm in the house before starting again on this project.
Even better than the above, is take some fiberglass, rockwool, or ceramic fiber batt, wrap it in some steel foil of some kind, seal it up air tight (welding), and pull a vacuum on it. Then on one side, take some stainless steel mesh, and paste NightHawkInLIght's Starlite like material into/onto the mesh. This is to protect the steel foil from super hot temps (You might be able to skip this part if you use pure or nearly pure Ti foil? But I'm not sure how easily Ti can be welded, and it is expensive AF). The combo of this would be unbeatable as to hot temp insulation. I would love to do this myself, but I don't have welding equipment or experience.
A rocket mass heater is what you want. Cob, stone. sand, gravel, water and just pockets of air are all used as thermal batteries. How low could you make the exhaust leaving the room? I have seen the air at the top of the room the same temp as the chimney exhaust. Pearlite in a water-glass matrix is a good insulator also.
If that carbon rock is the same material I'm familiar with and was used in large curing ovens, I called it FART ROCK. All you had to do was rub it on anything and it stunk like rotten eggs. I had lots of fun with some pieces of that stuff. The large ovens I'm taking about was used by Levi Strauss & co. for curing pants 👖 to be permanent press. That was back in the 70s and 80s in Little Rock, Arkansas USA.
Hi Rob, Thanks for another interesting video. Could you mold a burn tunnel out of carbon foam and have the carbon foam in direct contact with the combustion without the steel liner? How do you get hold of nitric acid? Don't tell me that you make it yourself! Thanks again Tim
You could push some bits of ceramic tile in from the air inlet. What would happen if you apply the foam in its gungy stage to the stove then run it ? Would it fully cure over time whilst increasing the burn area temperature? Once you hit about 800 degrees C would you not start generating Nox ?
Just make a chicken mesh cage around with a 4 inch gap, cotton plaster of Paris wrap it. And fill it with pumice sand or fine pebble. Very good insulation and good for 1600C
I have watched a lot of rocket stove videos and yours is by far the best at explaining the way they are intended to work and the necessity of a super-hot post-firebox area to efficiently burn prior combustion products at up to 1500degC. The carbon foam insulator sounds interesting but I can't see me being allowed to use the family oven, not least because of the electricity bill. You also reference at a key issue - a proper rocket stove needs to burn too hot for steel to be used in all of its construction.
Rhian Taylor: so if you’re making a rocket stove that similar to this, you may have to be willing to line it with fire bricks; if you’re looking to find an oven that you can use for making carbon foam insulation, you may be able to work it out with your family to set you up a place where you can set up a used, cheap toaster oven for this purpose, possibly outside in the shed or garage where they won’t have to smell it. Of course, if they agree to it, you may have to make it very clear at the outset about how much time is going to require to run, so that you can arrange with them, how you’re going to monitor it. I hope this works out for you, and that you will eventually come back to let us know how it turned out. :-)
Hi enjoy every video you produce Definitely look up this channel Interesting and worthwhile demonstration of refractory aircrete priority and diy rocketstove insulation
You can accelerate the fire coming from the pipe in the same way as in your rocket stove, a separate air intake produces more oxygen to burn the gases (like you have). Insert similar tubes on the side of the upward chimney and shortly before the end of the chimney bring them into the combustion chamber (perhaps 5 inches lower than the mouth of the chimney). This way you get superheated oxygen which speeds up the fire, and it doesn't hurt if you put something at the top of the pipe. The oven does not clog
You can also make carbon foam by carbonizing bread. I managed to make small pieces on my stovetop in a tin can filled with charcoal (to keep a reducing atmosphere). But bricks should be doable in a larger furnace in a similar way. It does tend to warp due to the shrinkage, but there's probably a way around that. Alternatively, the sugar method could also be done with another gas formation agent like sodium bicarbonate, which would be more accessible and also 'safer'.
"It is recognized as the most brilliant insulation." But yet, it's pitch black. I just love the English language. Non English speakers see contradictions everywhere within the language, while native speaker are not understanding all the fuss. Thank you for sharing this recipe. I was looking for an insulator material for the foundry I want to build.
lol - the same thing happens in all languages - double meanings are everywhere - collocation and culture takes care of most of it - non native speakers usually have a poor grasp of that whichever language we are talking about
Yes, the temps can get up to 2000-3000° F- enough to melt metal. At the very least, it can cause spalling & eventually degradation of the metal. It is usually NOT recommended to make them from metal.
I wonder if you could make a modified sugar mix, paint it on the stove and run it for a while to make an insulating layer. You might have to modify the stove slightly during this process, or somehow run it differently, since the stove gets way hotter than your recipe calls for.
That is what I was thinking! There should be a way to conform it around what you want to insulate somehow. Unless breaking it up into a powder and pouring into a box frame around the rocket stove would work?
@@robertpoynton9923 : : You could be looking for a clay or brick kiln or an outdoor pizza oven, or an improvised Raku kiln made of possibly a metal garbage can, fired with a propane cylinder…
@@daphneraven6745 I have a forge I used for knife making. I would need to work out how to regulate the temperature make it. Also not able to get nitric acid and not sure of the quantity of the substitute chemical that he mentioned, I couldn't find it in the paper he referenced.
I wonder if it's not easier to put Starlite on the whole of the RocketStove... I think that to shape the whole of the tube, it's easier than the CarbonForme. Thank you for the video it's good to know that the CarbonFrome exists and that you can do it yourself.
Love it as always! Tried carving a rocket stove out of spent mycelium bricks (as insulation and body) didn't really work yet... Any ideas on how to make an easy diy efficient oven for those temperatures? I'm assuming i need to make a functioning rocket stove first (;
What if you performed pyrolysis on the dried spent mycelium bricks? That would turns the bricks into something close to a carbon foam (though I don’t know how it’s density/porosity would compare to the described method)
If the stove was embedded into a mass of sand, in a fridge carcass for example ( laid on it's back) would the sand act as an adequate insulator for burning purposes but also collect heat that could be piped into a room?
Shouldn't the refractory material be on the inside of the steel to protect the steel, like the firebrick inside a wood stove? You said earlier in the video that the rockwool around the steel raised the temperature inside to dangerous levels capable of melting steel.
Hey Robert, great video! You should check out the new research on making carbon foam from bread. I definitely need to try the sugar method from this video.
Nicely done. Keep up the good work. Have you tried to making a battery with graphite and iron using zinc sulfate as a electrolyte if not please try I highly recommend. Graphite as + iron as -
I was wondering if using INCONEL metal would be sufficient at resisting the heat of the rocket stove without using the carbon sugar insulation Robert ??? Can the carbon resist having wood logs thrown at it ??? Thank you Sir for your help. I am in the process of making a rocket stove and would like to stay with metal more so than using bricks. Peace vf
Seeing this and how it is made I'm curious if a lazy person, or someone who didn't want to run their oven so long could simply paint the sugar mixture onto the rocket stove and fire it up. Possibly it wouldn't work as well put it should still cause carmelization, curious if it would burn off or if you restricted the airflow enough could it be made to form directly on the stove.
Very good, but effort involved? Nighthawkinlight and some others did some demonstrations using bread -- turns out toast carburizes nicely to a foam. Perhaps a mix of paper, sand, and scrap gypsum board, instead? Insulation would support the themal battery. Cost and effort should be less, and paper embedded in sand will also carburize over time. Maybe put your steam coils in the sand in addition to, or instead of the chimney?
it is a bit of effort but the pore size is more controlled and the result better - even so it's horses for courses and an easier route will give you a reasonable result just not a good result - but you go for what is good for you mate
Robert, there's another way to achieve nearly aerogel-like levels of insulation: Make an enclosure around what you want to insulate, and pour fumed silica into the void space. The fumed silica is essentially a powder insulation. It works incredibly well at stopping all modes of heat transfer because: 1) prevents convection by filling the volume with powder 2) the individual particles of fumed silica have minimal contact, essentially cutting off direct conduction of heat 3) it back-scatters radiant heat. The only thing you need to ensure is that there's an opening somewhere which is covered in some kind of filter fabric material so no pressure builds up, without any of the powder coming out. A poured fumed silica powder insulation should achieve far better insulation than any of the carbon foam without the problem of being flammable.
fumed silica is supposed to also be useful in making dilatant greases, Akin to ooblec but it doesn't go off. Fumed silica, and a carrier, say glycerol. A shaft turned disk rotating in it, offers little resistance at low rpm, but the resistance builds up to a point at which it's akin to locked solid. rpm drops and it loosens up again. nice simple rpm limiter for say rubber band powered models, or maybe even wind turbines
Even better than the above, is take some fiberglass, rockwool, or ceramic fiber batt, wrap it in some steel foil of some kind, seal it up air tight (welding), and pull a vacuum on it. Then on one side, take some stainless steel mesh, and paste NightHawkInLIght's Starlite like material into/onto the mesh. This is to protect the steel foil from super hot temps (You might be able to skip this part if you use pure or nearly pure Ti foil? But I'm not sure how easily Ti can be welded, and it is expensive AF). The combo of this would be unbeatable as to hot temp insulation. I would love to do this myself, but I don't have welding equipment or experience.
@@ThinkingandTinkering Well yeah. The best is only as good as the application it’s used for. keep in mind the various acids and oxygen and intense heat. that metal will only hang around so long. I think that material would be more suited for a kilm or smelter. i’m certainly going to keep that in my toolbox of knowledge.
Does the carbon foam lend itself to being machined, molded, or cast into shapes? If it is used to produce heat shields for spacecraft, then could it also be formed into a hollow insert to line the inside of the stove body? With the properties you describe, it would seem the ideal material for the interior of a stove or rocket mass heater. All of the surfaces where combustion takes place or the gas products flow for the secondary burn would mean more of the output as heat. Or would the carbon foam be too good at isolating the combustion? With no metal surface reaching the high temperatures, the combustion would not get hot enough to create the draft and secondary gas burn?
Where did you get the stirling engine from? I've been hunting for one for a while and no one seems to be making them... I've been trying yo price out the cost of Thermoelectrics instead but they just suck compared to stirling engines, It would be nice if I can get one made instead of having to hire a machinist to make one.
Instead of using the Stirling engine to produce electricity in this setup, I think it would be perfect to instead put a fan blade on the Stirling engine to push the hot air around the room. It's a space heater without electricity
was reading through the comments to see if anyone's asked, didn't see it so ima ask..... is the carbon foam process safe for in home ovens? presuming a persons ok with that resulting energy bill, are there any off gassing issues to worry about?
Thank you for the carbon fiber foam. We used sodium silicate to coat the inside of the pipes with. Stupid question - 1) Can I get nitric acid without getting on some government watch list. 2) What molar acid? I'm an armature and have to dispose of by products as well store the stuff safely in a ventilated area.
Hi from France ! Here too we have nasty laws, it's feasible to synthetize nitric acid at home by using 2 Do-It-Yourself ways. See NurdRage UA-cam Channel, he has made some. You can also ask to a private company to purchase some bottles for you. Always used for destroying tree's roots by pouring 37% HNO3 by farmers. It exist a glass chamber where a high voltage spark between tungsten electrodes will create HNO3 with ...air. See some UA-cam videos dealing with good old Birkeland-Eyde swedish process. Best regards !
@@ThinkingandTinkering Thank you. this very cold weather has me searching for better insulation for a few areas. Carbon foam is way too long a process to do large areas but I'm trying to do it over the holiday's in small batches. Happy New Year to you. Best wishes for 2023
Robert, when are you going to take all your videos and transcribe them into a book? There are many people who would buy that book, and you’d make a pretty Penny!
Cool, great to see new videos added to the carbon foam playlist! Any chance this carbon is conductive without needing to cook at kiln temps? Is there anything we could add to make the foam flexible? Would borax make it harder/stronger or ruin it by reacting with the acid? If its strong enough, a tile of carbon foam might make a great thermal barrier for the next thermal lag Stirling. Sorry for so many suggestions 😅 but this is exciting. I wonder how a carbon foam cooler would work.
if you add a little nickel salt to the sugar mix it will be conductive - the rest I don't really know - but sounds like someone has quit a bit of experimenting to do lol
Very interesting, but for this application I will just stick with kaowool and/or refractory cement. Given the energy cost to cook the carbon foam is a bit of a turn off for the return on investment.
If you heat rockwool up around 1000' C the fibers if breathed in it causes silicosis which is similar to asbestos I worked in the Aluminium industry and we were very aware of this issue and it is not an issue that should be made light of
You don't have to heat it up. Any rockwool dust of respirable size will cause damage in proportion to dust volumes and exposure time. Wear a mask and tight fitting goggles. One tip if you want to avoid itching is to take a cold shower after work. Hot showers open up the pores and tiny fragments get in and itch for days.
Wow. So the best would be to make the internal of the first combustion area lined with the Carbon Foam? No? This should save the mild steel from degrading over time and extend it's life. As long a you have air control, things shouldn't get out of control. Have you ever experimented with using TEC tiles to convert the heat passing through the tile to a heat-sink and then passing heated air to a cold room via central heating duct? Also, if you had enough T.E.C units (aka Peltier Tiles) you could power a small PC fan to then supercharge the air intake OR use for the driving of the air being heated into the place you want it to go. Rocket stove central heating. Turn scrap wood into heat in your house and the more you stop the central heater having to come on, the more you save. Another Idea I love is charging up a large insulated water tank - then making an outdoor camping shower OR use that for Hydronic heating in your house.
Which nitric acid? Please provide chemical formula in description. This would be specially useful for foreigners not understanding niuances of the language , like me.
What effort you go to, just to Educate us. I hope we all pass the Exam. You the best Teacher Ever.
lol - cheers mate
Robert Murray-Smith only “Masters” of trade can make people understand in a manner which is down to Earth and you are one of those. You humble me Esquire.
I didn't know about rocket stove, now it's my new favorite.
awesome - mine too lol
Again you" knocked it out of the park". Thanks Robert.
I have been looking into rocket mass heaters for barns/ garages, etc. for a few years now. I was shocked to see one in a house in a very cold environment where they did indeed melt the pipe used for the fire part, and had to re-line it with firebricks. Wow, definitely stupendously hot! There is also a video on here of heating a greenhouse with a form of mass heater and heating water as well, running copper pipes through the mass...the possibilities are very interesting. The idea of making stunning insulation from sugar is wild. Thanks for always bringing new ideas and ways to go about generating power, you always have interesting ideas.
I've had a bucket rocket stove for about a decade now, in the van for camping use. It's basically a steel bucket with a hole cut near the bottom. I stick a couple of large tin cans inside, cut to shape and taped together in an L shape, then fill between the cans and the bucket with some thermal mass. Latest incarnation is 50:50 plaster of Paris and sand. Now it runs hot as a forge, and stores heat like a sand battery. Trouble is, it's heavy as hell.
I have a cast iron Dutch oven full of sand that I put on top of it, run it outside on sticks, then use it to heat the hallway of this old sandstone building I live in, up in the Scottish Highlands.
I recall making toffee in my youth - several spoiled pans with an impenetrable carbon foam. It did not take long for my attention to wander and this was pre-smoke alarms so I am guessing 30 minutes on high should do it! The smoke was quite impressive.
Great series, so with a J style rocket stove with the combustion section replaced with a ceramic chamber, a water heat extractor in the exhaust and a heat pump to remove any residual waste heat, I should be able to provide the whole street with hot water and remove the need for gas heating this winter. Just need to organise the kids to feed in the twigs 24/7. If only we could solve the energy crisis so easily.. but maybe in the next video 😅👌👍
ahh - at last a sensible use for children lol
@@ThinkingandTinkering we'll make the forage twigs like they are twix
Rob you truly are awesome. Carbon foam is the best but very expensive so I made my own from a research paper. There will be a statue of you some day mate.
Oh, good. Finally, a use for all my research papers that never got published.
What you said is true but insulating the outside of the burn chamber and riser tube will keep the heat in as it's supposed to but at the same time cause the steel to get to a temperature that will burn itself out relatively quickly. You do gain efficiency when insulating the burn and riser tubes but the insulation must be on the inside so the steel remains at a low enough temperature to not burn itself out.
I suppose the marketing trick of carbon foam it that its the best insulator material. The best insulator is vacuum because heat literally cant move through it but I guess thats not really a material lol
That sugar recipe is amazing, I'll have to try that, thanks!
I've been interested in carbon foam insulation for a while after i learned you can basically take a cookie and hold in in the palm of your hand and point a blowtorch at it and hold it there for a shockingly long period of time before you start to feel the heat through the cookie as it actively produces an ablative carbon foam which effectively dissipates the heat
Oh Cool.
I saw someone, honey do carpenter here on yt I think, made a rocket stove out of aircrete inundated with water glass, so it was refractory, very insulative, and lightweight. He cast the mix inside a metal frame, for durability. It seems like you could do the stove out of just slip together Chimney pipe with that method. Might also be a good option for people to try.
good suggestion mate
Love the chat amendments. Question: What is up with your window blinds? Laundry line? Appreciate your mind. Keep it up. Mitch.
Good video. The fundamentals are covered now. Pearlite is not a bad insulator too.
Yep. Vermiculaite also.
I mix perlite with clay slip to keep it where I put it. Works a charm.
for sure mate and cheers
@@SundogbuildersNet a lime and water slip works well too
@@bigoldgrizzly
Lime can't really handle higher temperatures. It'll turn back to quicklime pretty quick. At least the bits that are in the biggest heat. Might not matter if the stuff on the outside holds it in. Just don't get it wet! ;)
@@SundogbuildersNet True, the lime filler/binder will breakdown to dust at 875 -900 deg C. I have used it contained between structures such as brick and pipes, where the physical strength of the insulation is of little importance. All firepots will degrade with time be they made of cob, vermiculate/clay binder fire bricks or steel. They have to put up with a lot of grief from oxidation and decarburisation of steels and the repeated expansion/contraction cycles, not to mention overexuberant use of pokers or ash rakes. Behind the tough 'working face' the insulation suffers less from these issues and in some cases can be recycled after the inevitable periodic stripdowns. Unless the firepot is to be built in expensive bespoke specialist cast porcelain type ceramic materials that can cope with temperatures of 1000 - 1400degC, it seems a bit pointless trying to get rocket stoves to run this hot. Better perhaps to accept running at lower temperatures and building with firebrick faces in the firepot and a vermucultie with binder encasing the whole. This makes for a structure which is easy to take down and rebuild..... got a bit off piste there .... and a little carried away....... ;
Rob, take a look at a foam made by Hilti CFS-FX. You can fill a box allow it to air cure and cut it into pieces.
Not bad in general, but neat carbon foam has a great disadvantage: it burns! To prevent this you can mix the sugar with fine quarz-powder, e.g. microsilica, before carbonizing the whole stuff. That leads to SiC wich forms in fire a thin layer of SiO2 on the surface, shutting off the oxygen from the carbon and prevents it from burning.
I wonder if a similar method might work with the bread method. It seems like a great base recipe to try all kinds of freaky stuff
nice idea mate cheers
@@ThinkingandTinkering See what I mean about the Chemistry?
Wouldn't be adding water-glass be more advantageous? As that is already liquid and water soluble, but it would definitely be a fine idea! Also borax or a phosphate salt could do the trick.
@@Luziferne The named substances are all possible but lead to lower melting products.
Wow! I have to say Robert, I find all your videos riveting, Your knowledge knows no bounds!🙂😉
Saved for reference! I'll take a look at this paper thanks! 👏🎉
there are quite a few methods mate - I believe zinc nitrate can be used as a blowing agent too
Brilliant as always. I can imagine this mess being poured over a mold and mold it to the shape you want.
Which I am going to try, BTW....as soon as I figure out where to buy Nitric Acid and what it is and how to use it in a sentence.
best DIY, non combustable/stable insulating refractory I found for "usual" high temps is aluminium oxide (blasting grit), pearlite/vermiculite, with sodium silicate used as a binder...
works fine for a charcoal fired aluminum melting furnace. Though it did melt before the steel did when I experimented using it as a liner for an arc welder powered carbon arc furnace/crucible , in the hope of being able to melt a handful of steel nails, and maybe cast the metal. (i guess it might turn into cast iron due to carbon from the rods) . Under same conditions a starlight type mixture expanded into carbon foam, and worked fine until it was glowing white hot, and then ignited due to air getting in through the holes in refractory body from prior experiments with gas heating. steel nails had clearly started to melt, as they had started to weld themselves together.
fascinating mate - thanks for sharing
Can you cast and fire the carbon foam in situ around the lower section of the stove, lower the stove itself into an appropriate container with the sugar solution, and fire it up for the two days? Maybe instead of while it is a fluid you could pour the sugar solution, when it has thickened, to a plaster consistency?
I figured out an easier, faster, and more efficient way to use vacuum insulation for these. Take large, wide mouth mason type jars. Use something like a Pump N Seal system (fairly inexpensive) to pull a vacuum on it.
Since that uses little tabs to seal, you'll have to use copper or aluminum tape to better/more long term seal it. Then the entire top is going to be sealed with Water glass.
After the jar is sealed with Water glass, then you connect various jars with a combo of water glass and fiberglass cloth.
After you get the sides of the structure made, mix some clay with fumed silica and/or perlite and coat at least the inside and top of the structure with a thinnish layer of the clay mix. Make sure the top of the jars have a thicker layer to protect the lids etc from too much heat.
You're on your own as far as the ceiling etc but also use insulation. Since 32oz mason jars are a few inches wide, along with the 28" or so Hg of vacuum pulled in same, this will provide just a ridiculous degree of thermal insulation, and I mean *ridiculous.* Talking something like R150 in the center, plus the little bit that the insulated clay mix adds to the system.
Robert, have you experimented with Aircrete or aerated concrete as it's known? It's basically Portland cement or other concrete mix including quickcrete that you add whipped dish soap/water mix in place of water you normally add. The trick is to mix soap and water into shaving cream consistency. Why I'm bringing up is because it's like formable asbestos and it's very insulative, it's also lightweight and even floats. You can cut it with a saw, drill it, screw into it and it's amazing stuff as you would say. A 1/2" layer will protect an item from the heat of a blowtorch. Anyway, awesome videos, I never miss them and learn a ton from you.
Hello, this sounds very interesting. You don't happen to have any videos on making such a material? Thanks for the info.
I agree with Michael, would love a video
Just guessing here, but I think Aircrete would be short-lived, since a rocket stove can easily reach temperatures above what concrete can withstand.
I've heard this stuff called 'foamed concrete ' and was used on parts of the Canary Wharf project, London UK as it was do light. I'd imagine it would work great as insulation and or fire protection
Check out aircrete harry
Have you tried air crete. Much easier to make in big quantities.
Also amazing insulative properties and if you also put waterglass on it, it becomes super strong and can even withstand the flowing hot air. That is the/a way to go ! :-) cheers !
Your knowledge base is absolutely incredible!
You can make:
Diodes (No one else online knows how to make diodes w/o expensive equipment)
Carbon foam (is this Starlite?)
🪙🏝🏆Unlocked!
●First pick to have to survive on an island with. If that's an award, you've won.
And there was me using doorsteps of white bread, sticking them in an old biscuit-tin along with some sawdust (to fill any remaining space) and a few holes in the top and bunging it onto a bonfire!
It works, but not very tidy, and no-doubt very impure.
Yes, I would go for bread too. This paper (below) claims it has compressive strength of 3.6 MPa with a density of just 0.29 g/cm3
Yuan, Ye, et al. "Multifunctional stiff carbon foam derived from bread." ACS applied materials & interfaces 8.26 (2016): 16852-16861.
This time around, I must remember to take the battery out of every smoke alarm in the house before starting again on this project.
if it works it works. mate lol
Even better than the above, is take some fiberglass, rockwool, or ceramic fiber batt, wrap it in some steel foil of some kind, seal it up air tight (welding), and pull a vacuum on it. Then on one side, take some stainless steel mesh, and paste NightHawkInLIght's Starlite like material into/onto the mesh. This is to protect the steel foil from super hot temps (You might be able to skip this part if you use pure or nearly pure Ti foil? But I'm not sure how easily Ti can be welded, and it is expensive AF).
The combo of this would be unbeatable as to hot temp insulation. I would love to do this myself, but I don't have welding equipment or experience.
A rocket mass heater is what you want. Cob, stone. sand, gravel, water and just pockets of air are all used as thermal batteries. How low could you make the exhaust leaving the room? I have seen the air at the top of the room the same temp as the chimney exhaust. Pearlite in a water-glass matrix is a good insulator also.
If that carbon rock is the same material I'm familiar with and was used in large curing ovens, I called it FART ROCK. All you had to do was rub it on anything and it stunk like rotten eggs. I had lots of fun with some pieces of that stuff. The large ovens I'm taking about was used by Levi Strauss & co. for curing pants 👖 to be permanent press. That was back in the 70s and 80s in Little Rock, Arkansas USA.
Hi Rob, Thanks for another interesting video. Could you mold a burn tunnel out of carbon foam and have the carbon foam in direct contact with the combustion without the steel liner? How do you get hold of nitric acid? Don't tell me that you make it yourself! Thanks again Tim
You could push some bits of ceramic tile in from the air inlet. What would happen if you apply the foam in its gungy stage to the stove then run it ? Would it fully cure over time whilst increasing the burn area temperature? Once you hit about 800 degrees C would you not start generating Nox ?
Just make a chicken mesh cage around with a 4 inch gap, cotton plaster of Paris wrap it. And fill it with pumice sand or fine pebble.
Very good insulation and good for 1600C
what about using the vacuum off the chimney to run generator?Keep up the great work!!
I have watched a lot of rocket stove videos and yours is by far the best at explaining the way they are intended to work and the necessity of a super-hot post-firebox area to efficiently burn prior combustion products at up to 1500degC. The carbon foam insulator sounds interesting but I can't see me being allowed to use the family oven, not least because of the electricity bill. You also reference at a key issue - a proper rocket stove needs to burn too hot for steel to be used in all of its construction.
Rhian Taylor: so if you’re making a rocket stove that similar to this, you may have to be willing to line it with fire bricks; if you’re looking to find an oven that you can use for making carbon foam insulation, you may be able to work it out with your family to set you up a place where you can set up a used, cheap toaster oven for this purpose, possibly outside in the shed or garage where they won’t have to smell it.
Of course, if they agree to it, you may have to make it very clear at the outset about how much time is going to require to run, so that you can arrange with them, how you’re going to monitor it.
I hope this works out for you, and that you will eventually come back to let us know how it turned out. :-)
6 inch( stove pipe) rocket stove. Mark Thomas.
Rocket stove 3.0 w/ pellet feeder. Andy Man.
Simple assembly. No welding.
Hi enjoy every video you produce Definitely look up this channel Interesting and worthwhile demonstration of refractory aircrete priority and diy rocketstove insulation
cheers mate
Thought provoking as always 👌🏼 and I Can't wait to see you make a steam engine Rob 😉 👍🏻🤘🏻🖖🏻
love steam mate!
You can accelerate the fire coming from the pipe in the same way as in your rocket stove, a separate air intake produces more oxygen to burn the gases (like you have). Insert similar tubes on the side of the upward chimney and shortly before the end of the chimney bring them into the combustion chamber (perhaps 5 inches lower than the mouth of the chimney). This way you get superheated oxygen which speeds up the fire, and it doesn't hurt if you put something at the top of the pipe. The oven does not clog
Thanks for the info!
So excellent! I was thinking you might try your starlite formula, but this seems much better.
nah - too. many others trying Starlite and nighthawkinlight did such an awesome job of it
Thank you! I'm gonna try!
But I'm worried about inhaling heated nitric acid fumes
There is a Chinese paper on carbonising bread also you could just try carbonising cinder toffee.
A cheap alternative is wood ash contained in a light sheet metal cladding
If the steel is insulated on the outside will it add to the problem of too much heat in the steel. What if the insulation was on the inside?
The carbon foam looks very interesting as a project. Fire bricks are fairly cheap, though.
Fire bricks handle heat
but don't insulate well.
You can also make carbon foam by carbonizing bread. I managed to make small pieces on my stovetop in a tin can filled with charcoal (to keep a reducing atmosphere). But bricks should be doable in a larger furnace in a similar way. It does tend to warp due to the shrinkage, but there's probably a way around that. Alternatively, the sugar method could also be done with another gas formation agent like sodium bicarbonate, which would be more accessible and also 'safer'.
It might even be interesting to wrap the stove in bread and run it, and let the carbon foam form in real time around the setup.
good foaming agents are ammonium chloride or zinc nitrate - as for bread - sure it works just not as well
Can you use ceramic fiber blanket? I use it in my glass blowing kilns and it handles 1300f atleast
There is a fragile blue tinted foam type insulator Aerogel Nile Red made some.
This is about the 5th time I have gone on line to look at how people build their own [XYZ], and.... there you are 😃
"It is recognized as the most brilliant insulation." But yet, it's pitch black. I just love the English language. Non English speakers see contradictions everywhere within the language, while native speaker are not understanding all the fuss. Thank you for sharing this recipe. I was looking for an insulator material for the foundry I want to build.
lol - the same thing happens in all languages - double meanings are everywhere - collocation and culture takes care of most of it - non native speakers usually have a poor grasp of that whichever language we are talking about
Yes, the temps can get up to 2000-3000° F- enough to melt metal. At the very least, it can cause spalling & eventually degradation of the metal. It is usually NOT recommended to make them from metal.
I wonder if you could make a modified sugar mix, paint it on the stove and run it for a while to make an insulating layer. You might have to modify the stove slightly during this process, or somehow run it differently, since the stove gets way hotter than your recipe calls for.
that's an interesting idea mate - I like it thanks for sharing
That is what I was thinking! There should be a way to conform it around what you want to insulate somehow. Unless breaking it up into a powder and pouring into a box frame around the rocket stove would work?
I've been looking into large DIY ovens and you could make a powder coating oven to put it in, that's if you have other uses for a large oven 🤣
@@robertpoynton9923 : : You could be looking for a clay or brick kiln or an outdoor pizza oven, or an improvised Raku kiln made of possibly a metal garbage can, fired with a propane cylinder…
@@daphneraven6745 I have a forge I used for knife making. I would need to work out how to regulate the temperature make it. Also not able to get nitric acid and not sure of the quantity of the substitute chemical that he mentioned, I couldn't find it in the paper he referenced.
I wonder if it's not easier to put Starlite on the whole of the RocketStove... I think that to shape the whole of the tube, it's easier than the CarbonForme.
Thank you for the video it's good to know that the CarbonFrome exists and that you can do it yourself.
it would be easier mate - just not as good
Great Stuff Rob
Bless Up Fella
cheers mate
Love it as always!
Tried carving a rocket stove out of spent mycelium bricks (as insulation and body) didn't really work yet... Any ideas on how to make an easy diy efficient oven for those temperatures? I'm assuming i need to make a functioning rocket stove first (;
What if you performed pyrolysis on the dried spent mycelium bricks? That would turns the bricks into something close to a carbon foam (though I don’t know how it’s density/porosity would compare to the described method)
If the stove was embedded into a mass of sand, in a fridge carcass for example ( laid on it's back) would the sand act as an adequate insulator for burning purposes but also collect heat that could be piped into a room?
Shouldn't the refractory material be on the inside of the steel to protect the steel, like the firebrick inside a wood stove? You said earlier in the video that the rockwool around the steel raised the temperature inside to dangerous levels capable of melting steel.
You can try saturating multiple layers of fiberglass with a thick sugar broth and heating it so that the sugar carbonizes.
nice idea mate
Hey Robert, great video! You should check out the new research on making carbon foam from bread. I definitely need to try the sugar method from this video.
AvE did this and made a little forge out of a loaf 😂 Pretty cool stuff
I was thinking of doing that myself! Good to know it works. I have a nice loaf drying at home.
I did mate - I like it - I also like the sugar the carbon is more controllable and closer pores
I make carbon foam slices every morning - then add butter and marmalade - yummy !!
Brilliant. Although is sand not just as effective and easier to install ?
Nicely done. Keep up the good work.
Have you tried to making a battery with graphite and iron using zinc sulfate as a electrolyte if not please try I highly recommend.
Graphite as + iron as -
Thanks for the idea!
@@ThinkingandTinkering No problem. I love to share ideas.
I love your zest for life.
cheers mate
Show us how to control the heat just like we do in regular stoves please. Regards
I was wondering if using INCONEL metal would be sufficient at resisting the heat of the rocket stove without using the carbon sugar insulation Robert ??? Can the carbon resist having wood logs thrown at it ??? Thank you Sir for your help. I am in the process of making a rocket stove and would like to stay with metal more so than using bricks. Peace vf
Seeing this and how it is made I'm curious if a lazy person, or someone who didn't want to run their oven so long could simply paint the sugar mixture onto the rocket stove and fire it up. Possibly it wouldn't work as well put it should still cause carmelization, curious if it would burn off or if you restricted the airflow enough could it be made to form directly on the stove.
I'm wondering if carbon foam could be made in aircrete🤔 could charcoal be added to the aircrete mix and have similar properties.
Very good, but effort involved? Nighthawkinlight and some others did some demonstrations using bread -- turns out toast carburizes nicely to a foam. Perhaps a mix of paper, sand, and scrap gypsum board, instead? Insulation would support the themal battery. Cost and effort should be less, and paper embedded in sand will also carburize over time. Maybe put your steam coils in the sand in addition to, or instead of the chimney?
it is a bit of effort but the pore size is more controlled and the result better - even so it's horses for courses and an easier route will give you a reasonable result just not a good result - but you go for what is good for you mate
Thank you for sharing
glad you liked it mate - cheers
There is a gentleman on Uribe that insulates his rocket stove with air crete, and even builds an aircrete generator
Robert, there's another way to achieve nearly aerogel-like levels of insulation: Make an enclosure around what you want to insulate, and pour fumed silica into the void space. The fumed silica is essentially a powder insulation. It works incredibly well at stopping all modes of heat transfer because:
1) prevents convection by filling the volume with powder
2) the individual particles of fumed silica have minimal contact, essentially cutting off direct conduction of heat
3) it back-scatters radiant heat.
The only thing you need to ensure is that there's an opening somewhere which is covered in some kind of filter fabric material so no pressure builds up, without any of the powder coming out.
A poured fumed silica powder insulation should achieve far better insulation than any of the carbon foam without the problem of being flammable.
fumed silica is supposed to also be useful in making dilatant greases, Akin to ooblec but it doesn't go off. Fumed silica, and a carrier, say glycerol.
A shaft turned disk rotating in it, offers little resistance at low rpm, but the resistance builds up to a point at which it's akin to locked solid. rpm drops and it loosens up again. nice simple rpm limiter for say rubber band powered models, or maybe even wind turbines
Even better than the above, is take some fiberglass, rockwool, or ceramic fiber batt, wrap it in some steel foil of some kind, seal it up air tight (welding), and pull a vacuum on it. Then on one side, take some stainless steel mesh, and paste NightHawkInLIght's Starlite like material into/onto the mesh. This is to protect the steel foil from super hot temps (You might be able to skip this part if you use pure or nearly pure Ti foil? But I'm not sure how easily Ti can be welded, and it is expensive AF).
The combo of this would be unbeatable as to hot temp insulation. I would love to do this myself, but I don't have welding equipment or experience.
Thank you Robert nice video. Do you know how water breathable the carbon foam is?
They usually place it in a bucket and fill it with plaster of Paris and perlite and it’s usually sufficient enough
indeed it is - just not the best
@@ThinkingandTinkering Well yeah. The best is only as good as the application it’s used for. keep in mind the various acids and oxygen and intense heat. that metal will only hang around so long. I think that material would be more suited for a kilm or smelter. i’m certainly going to keep that in my toolbox of knowledge.
Does the carbon foam lend itself to being machined, molded, or cast into shapes? If it is used to produce heat shields for spacecraft, then could it also be formed into a hollow insert to line the inside of the stove body?
With the properties you describe, it would seem the ideal material for the interior of a stove or rocket mass heater. All of the surfaces where combustion takes place or the gas products flow for the secondary burn would mean more of the output as heat.
Or would the carbon foam be too good at isolating the combustion? With no metal surface reaching the high temperatures, the combustion would not get hot enough to create the draft and secondary gas burn?
Where did you get the stirling engine from? I've been hunting for one for a while and no one seems to be making them... I've been trying yo price out the cost of Thermoelectrics instead but they just suck compared to stirling engines, It would be nice if I can get one made instead of having to hire a machinist to make one.
Instead of using the Stirling engine to produce electricity in this setup, I think it would be perfect to instead put a fan blade on the Stirling engine
to push the hot air around the room. It's a space heater without electricity
was reading through the comments to see if anyone's asked, didn't see it so ima ask..... is the carbon foam process safe for in home ovens? presuming a persons ok with that resulting energy bill, are there any off gassing issues to worry about?
Thank you for the carbon fiber foam. We used sodium silicate to coat the inside of the pipes with.
Stupid question - 1) Can I get nitric acid without getting on some government watch list.
2) What molar acid? I'm an armature and have to dispose of by products as well store the stuff safely in a ventilated area.
if you can't get nitric acid you can also use ammonium chloride or zinc nitrate mate
@@ThinkingandTinkering Thank you sir.
Hi from France ! Here too we have nasty laws, it's feasible to synthetize nitric acid at home by using 2 Do-It-Yourself ways.
See NurdRage UA-cam Channel, he has made some. You can also ask to a private company to purchase some bottles for you. Always used for destroying tree's roots by pouring 37% HNO3 by farmers. It exist a glass chamber where a high voltage spark between tungsten electrodes will create HNO3 with ...air.
See some UA-cam videos dealing with good old Birkeland-Eyde swedish process.
Best regards !
just remember not to put cellulose or glycerine on the same order list ;
@@ThinkingandTinkering Thank you. this very cold weather has me searching for better insulation for a few areas.
Carbon foam is way too long a process to do large areas but I'm trying to do it over the holiday's in small batches.
Happy New Year to you. Best wishes for 2023
Where can I buy nitric acid? I wonder if you couldn’t paint the rocket with the sugar solution and use the rocket to cure it?
AWESOME!!! 🤠👍
Burned toast works well too.
yep - it's all carbon foam mate
Robert, when are you going to take all your videos and transcribe them into a book? There are many people who would buy that book, and you’d make a pretty Penny!
that would be a lot of work mate - but nice idea cheers
Off gassing. Sorry. Could i use a thin sheet of this for ultra-batteries?
What would the r value per inch be of this foam if we used it in a home ?
Awesome! 👏
cheers mate
Great video,
The problem is that DIY people cannot buy nitric acid.
you can use ammonium chloride as I said in the video - or zinc nitrate
@@ThinkingandTinkering sorry I missed it.
I believe the best insulation is also the cheapest. White wood ash. The frustrating thing about white wood ash is… we throw it away
nice tip mate - cheers
Cool, great to see new videos added to the carbon foam playlist! Any chance this carbon is conductive without needing to cook at kiln temps? Is there anything we could add to make the foam flexible? Would borax make it harder/stronger or ruin it by reacting with the acid? If its strong enough, a tile of carbon foam might make a great thermal barrier for the next thermal lag Stirling. Sorry for so many suggestions 😅 but this is exciting. I wonder how a carbon foam cooler would work.
if you add a little nickel salt to the sugar mix it will be conductive - the rest I don't really know - but sounds like someone has quit a bit of experimenting to do lol
could run the exhaust though a cheap califont core in a closed loop to stirling engines with something that boils at a very high temp
nice idea mate - cheers
Very interesting, but for this application I will just stick with kaowool and/or refractory cement. Given the energy cost to cook the carbon foam is a bit of a turn off for the return on investment.
Mineral wool, high temp rating, easy to handle, cheap too.
for sure mate - just not as good
With current energy prices if i need to leave something in the oven for 2 days, it might be cheaper to buy the actual carbon foam
If you heat rockwool up around 1000' C the fibers if breathed in it causes silicosis which is similar to asbestos I worked in the Aluminium industry and we were very aware of this issue and it is not an issue that should be made light of
You don't have to heat it up. Any rockwool dust of respirable size will cause damage in proportion to dust volumes and exposure time. Wear a mask and tight fitting goggles. One tip if you want to avoid itching is to take a cold shower after work. Hot showers open up the pores and tiny fragments get in and itch for days.
Perlite for the win.
for sure
Wow. So the best would be to make the internal of the first combustion area lined with the Carbon Foam? No? This should save the mild steel from degrading over time and extend it's life. As long a you have air control, things shouldn't get out of control. Have you ever experimented with using TEC tiles to convert the heat passing through the tile to a heat-sink and then passing heated air to a cold room via central heating duct? Also, if you had enough T.E.C units (aka Peltier Tiles) you could power a small PC fan to then supercharge the air intake OR use for the driving of the air being heated into the place you want it to go. Rocket stove central heating. Turn scrap wood into heat in your house and the more you stop the central heater having to come on, the more you save.
Another Idea I love is charging up a large insulated water tank - then making an outdoor camping shower OR use that for Hydronic heating in your house.
A steam engine would definitely be more efficient than a stirling engine. Great idea, btw.
for sure mate
Wonder if you can just use starlite instead.
would that carbon felt work in a similar fashion?
You can make something similar to that carbon foam burning slices of bread in an oven.
yes indeed
Which nitric acid? Please provide chemical formula in description. This would be specially useful for foreigners not understanding niuances of the language , like me.
I wonder how this stuff holds up to vibration… what if you use this as insulation on a vehicle?
Sulphuric acid instead of nitric and it grows before your very eyes.