Case Hardening 101 - Heat Treatment Oversimplified
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- Опубліковано 20 тра 2024
- G'day everyone,
In a recent project I had to case harden some low carbon steel in order to raise the carbon content, so that I could quench harden it. I got a few questions about the method that used. In this video I would like to show you some of the test parts that I did before I case hardened the vise, as well as some of the improvements that I have made to the method. I hope you find the video useful.
#machining #heattreatment #casehardening
Useful Link: www.woodworkforums.com/archiv...
Timestamps
0:00 - Introduction (What is Case Hardening)
1:02 - Applications For Case hardening
4:01 - Carburization
6:14 - Pack Hardening
11:15 - Quenching and Normalizing Steel
13:59 - Water and Brine Quenching
15:14 - Sodium Carbonate + Charcoal - Наука та технологія
I studied metallurgy for years in college and after. I rarely see UA-cam presentations of heat treatment without misinformation. You did an accurate and clear job of presenting a complex subject and it was entertaining.
Mare, can you recommend any good reads for hobbyists? I have no background in metallurgy, though there are some instruments I would like to make for my work.
@@therealKJMD college books taught me the most about metallurgy to be fair 😂 I would try to search for schoolbooks and machinist handbooks
@@dodgydoode111
@@therealKJMD I'd really recommend Machinery's Handbook, there is tons of extremely good info in there on most metalworking & mechanical engineering topics. Current editions are kinda expensive (150 USD for the current edition), but older editions used off ebay are just fine for hobbyist use. Don't buy this book off of amazon, most of the listings there are counterfeits (at least in the US, don't know about AU) and can possibly have misprints. I paid ~20 USD for my copy of the 26th edition, I believe they are currently on the 31st edition.
I want to harden my gears in my tranny because why not.
I had no idea the sodium carbonate and brine solution could make such a big difference! Super interesting and well presented!
Thankyou
We have had many good metallurgists over the years and they are all wrong..Do not except that..
We did that in high school machine shop.
I learned 10 times more about case hardening from your video than I learned from my 3-month heat treating course at technical college.
That causes one to wonder about the adequacy/validity of everything else they taught you.
@@seeharvester Thats if they are wrong
😅
"Traditionally you would use wrought iron, but we no longer live in the 18th century" 😂 I'm so glad you're able to take advice from others and admit some mistakes. That's a very hard thing to do. You weren't bad with your method though and in your case I think case hardening would be a good idea. You definitely do a ton of research to find different methods for doing a thing, their effectiveness, and problems with them, and weigh the cost and labor for each of them. It's only natural to miss the occasional detail but I honestly think you do a fantastic job on your research and it's very insightful to listen to! And of course you do test things for yourself so you're not just relying on book knowledge and know that slight adaptations you make will still produce the same result. Well done!
This is a compliment, this will save me a lot of time, I enjoy reading however work takes mostly all my time, and a lot of times I just need the answers to the test fast, this was a great thing you are narrating, and illustrating and will save me and others time and that money thing we need, and it's always a topic I am interested in too. You have from day one provided me with all like-minded topics and interests thank you for all you do hope to see more. Good day to you.
Thankyou, glad you enjoyed the video.
An old machinist showed me several methods of case hardening for plow points and the like, harking back to "olden days" before cars and such. My favorite was an iron box filled with small pieces of bone and antler, which was supplied by my breaking up dead critters. The box was about 3/8ths of an inch thick, which closed with a snail cam. He would then chuck it in the forge and I would get to work pumping the bellows to his satisfaction. I was pleased to stop when he figured it was time enough and he would let the fire die for the night. In the morning I would drag out the box and empty it. The hardening usually brought out some colors on the parts. For the tempering, he used rendered bear fat because it would not crack or check the metal. Just thought I might mention a different method. Good video, thanks.
I'm afraid bear fat would be tad difficult to get nowadays... ;-) Also, that "charred animal stuff" (charred leather in this case) method was shown by Chris from Clickspring channel - "Antikythera Fragment #4 - Ancient Tool Technology - The First Hardened Steel?" (ua-cam.com/video/V_Mp1fNzIT8/v-deo.html).
That method was indeed "used before cars and such"...
@@MrKotBonifacy I do appreciate your letting me know about that. I've heard tell of that antikythera. It was supposed to be older than the Sumerians (I think that was who, could have been the Greeks), and I do believe I heard tell that it was brass or bronze. so that could help you date it, if an age was needful. I'll check out that video tomorrow, since it's gotten late.Nice to know that the old ways of doing things can still be counted on.
Excellent video! Real world hands on demonstration.
It's great seeing the amount of skill and knowledge you've improved over the past year alone! Keep it up!!
Thankyou, had a lot of fun doing to
12:06 @@artisanmakes
Thanks for the great overview and taking all the time to do the comparison testing. From personal experience I know how much time can be consumed by experimentation to validate the things people suggest.
Not to mention the exhausting effort needed to comb both old literature and pinpointing the specific relevant information amongst the mind boggling plethora of search returns that only pertain to the general topic your searching.
You may have called it a simple introduction but from my perspective even without covering some of the finer points on the subject, you did a fantastic introduction/Q & A that would help over 95% of the people wanting to case harden parts, 🍻.
Cheers, That is very kind of you. Definitely not 100% comprehensive but I hope it helps.
When quenching a part, you should move it rapidly in the quenching medium, regardless what it is. Move it in a figure of 8 or circles and up and down. This movement prevents the steam jacket. If only a section of an part should be hardened, move the part up an down, to achieve a smooth transition from hardened to not hardened material.
This was a great guide supplement! Tells you quite a lot of info that tends to get skipped over in step by step guides and has a lot of good suggestions to make everything just work more smoothly! Really looking forward to trying this out !
The quality of your vids increases every time. Your explanations are cogent and concise and I’m really glad I found your channel 🙂
Thankyou, that is very kind
Without really knowing what I was doing, I managed to case harden some model locomotive parts using almost exactly the same process you've shown. I did use the sodium carbonate too. I've read that old fashioned blood and bone fertiliser is a good source of carbon but most modern fertiliser has other additives and I wouldn't trust it. Apparently, boot leather can also be used. Good video on a not widely documented topic.
Cheers Preso. The 1st edition machinery handbook that I have does reference crushed up bone as a pack hardening material, although it seems to be absent in later versions. Not sure about fertilizer but it could have some nitriding effects. I might have to look into that. Cheers
Well done, and very informative. I'll be using this video as a reference in a future.
I’ve heard about pack carburize but I have never done this. Back in the mid 90s I got a job at a local commercial/tooling heat treatment shop. I first started running the salt pots running tooling O-1, O-6, S5 and many more tooling materials. It was a salt to salt or salt to oil process. I moved on to run the vacuum furnaces, temper and endo furnaces. At least a few years in Each department. After 10 years of working in this tooling shop I decided I wanted to learn more and ended up getting a job at the words biggest heat treatment companies (BTP) this was one great experience that I will always be grateful for. I started as a vacuum operator, moved to a temper furnace operator, Nitride supervisor, shop foreman, production manager and finally plant manager. All these jumps was within a 12year time period not overnight. By this time I had 22years experience and made a decision to slow things down, I moved back to my first job as a facility manager. I am now in charge of the furnaces and future development of the plant. But I always love to hit the floor and reach the new guys a few tricks, especially the guys that show interest in the process.
But getting back to carburize, I’m not to familiar with pack carburize since this is not allowed in aerospace parts. We process the parts in a furnace with temperature and carbon controlled instruments. But for a tooling part this seems to be good enough, if it fails you just try again.
I might make some videos on the process using controlled instruments. I’ll see if I have time this year.
That is great for you to accomplish a career in a very important field. I'm a machinist 45yrs, worked tool & die 2 yrs and learned some heat treating tool steels. It is an enormous field to learn. Thanks for your inspiring story. You are proof that we can accomplish big things if we work hard and keep learning, move forward !!
I have a question for you! Heat treating knives, the data sheets demand a preheat to equalize.
I just put the knives in at cold, and ramp as fast as it goes up to aus temp. Shits getting hard, so it’s working so to speak but I’m just wondering if I can maximize everything. I want to heat treat these knives as good as I possibly can.
The data sheet for m2 suggests ramping 400 degrees f per hour up to normalize temp (like 1550f) then rapid ramp from there to aus. I’m assuming this is for large tooling parts not thinner cross sections right?
And finally. I’m planning on making some knives from forged a11, the forging range says 1700f, do I have a tiny window? Or what? Can I reverse the or what? I’m assuming I’ll cycle the material after forging but I don’t want to do any permanent damage to the grain or carbide or anything.
Oh yeah and sorry, I also want to forge weld simple stainless to these high carbide tool steels like a11, would I need to do that in a tool wrap, with argon?
You have my dream job. If I didn’t go into psychosis I’d be graduated from Colorado school of mines by now. Getting my rocks off in the home shop now.
I watched with fascination and awe at you making the video on small home machinery and made comment to such . But boy you just took it to a whole new level in this video you are very informed and pass that knowledge over easily Thank you for such facinating content
That was brilliant - you've obviously done a ton of research, and I learned a lot watching. Thank you.
What a fine lecture rich in content. So fine. Thank you !
brilliant video, very well made!
I worked in the tool making industry many years ago and we would case harden low carbon steel in a non sealed box packed with charcoal. We would heat treat tool steels in the same un sealed boxes but packed with cast iron chips to prevent carbon being lost from the steel.
Great VJO! best I have ever seen explaining case hardening!!!!!!!! I am subscribed!
very well done! i like the in depth approach in stead of "this works for me an i have loads of experience"
What a great guide for someone who's really interested in these topics.
I thoroughly enjoyed that video and learned a ton. Ty!
You have made a VERY GOOD video on this topic. Congratulations!
So engrossing! Marvelous video.
⭕️ new to this side of metal work... and i thank you for your time and good sir
This is the best information that I was in need. THANKS A LOT 🌹
Excellent video & discussion! From time to time, a case hardened part is far more efficient to make and use for my needs. Thanks for taking the time to better explain the process.
Awsome, hope this video helps you in the future. Cheers
Nice explanation. For future projects I would suggest not using Linseed oil. The modern process for producing it leaves behind some impurities in the oil that in and of themselves cause upredictable results. Actually, canola oil makes a passable quench medium if you don't have a right proper quench oil like Parks. Maybe in the future you could repeat your experiment when you are on another project and use Canola and test the results you get.
That could explain why it was mentioned in the earlier machining books but is suspiciously absent from the more modern books :)
I think all the seed oils have low cooling rates (too low) in the vicinity of pearlite formation. I know the blood Knife Steel Nerds has discussed that at length.
@@hunterbidensaidslesion1356 Probably, but with what I am doing, it probably doesn't matter too much.
Canola doesn’t fully quench. Maybe something 1/8 and under but research has been done suggesting you cannot get a full quench.
Parks is abundant as hell now. About the same price as canola. No excuse imo but time. Brine if nothing else.
👍This channel just keeps getting better and better. Thanks for the excellent explanation! The short technical "lecture" was really well written and explained, and the pace that you narrate is very easy to listen to, without any rambling. Well done!
One question - what state are you located?
I recently read a 1925 patent, it said to use sodium bicarbonate. Which could make sense. It breaks down at a low temp to CO2 and sodium carbonate
This would fill the chamber with CO2 before it gets red hot. This would displace the air and increase the amount of CO the carbon could produce. It also said to use a large proportion of hard wood sawdust. I assume this would reduce the density of the packing to allow the CO to defuse to the part.
Thanks for sharing the knowledge! It’s a really good compendium.
Well made tutorial, thanks for sharing.
Good information.
Thanks for sharing.
Thank you very much for the informative video. You have done an excellent job producing it. Your vice looks very nice as well. I have not done any case hardening since high school in the mid 60"s at which time we used kasenit and I understand it is no longer available. I did use 10% sodium carbonate as a catalyst and my final product turned out just as I wanted. I made a couple wear parts for a forming die and solved the problem- thanks.
Thanks again and keep up the good work.
Thanks for such great content. Living down under with the super high cost of specialty alloys (and pretty much everything else except sunshine) forces us to use our ingenuity which is to our benefit.
Thanks for sharing so much 👍🏼
Man that was a perfect explanation, Excellent Job! I have the same "low carbon steel sources" problem!
I was just researching for this! Thanks! 😊🌎✨
Great video mate, thanks for the info.
I always heard the term case hardened bolts , but never really knew what it meant other than it was harder , then a couple of years ago I saw some videos where they were case harding gun parts with the same method of heating it with charcoal
Great video great explanation . Thanks
Great Video. As a chief engineer in the gas turbine industry I have designed many heat treated nickel, cobalt, steel, titanium and aluminum based super alloys parts, but I don't normally don't get to see the step-by-step details of how the process works. All beatings in the gas turbine world get case hardened mostly using M50-Nil as the base alloy. Even in ceramic bearings, the inner and outer races are still case hardened steel.
I worked as a heat treater for about 12 years in WA state. We used induction, molten salt baths, open flame and endothermic gas electric furnaces with internal quench chambers to case harden. Carbon flows like electricity as it tries to reach a neutral carbon level. In a high carbon environment a low carbon material will absorb carbon. A high carbon steel in a low carbon enviornment will lose carbon. The higher the temperature the faster a material will absorb or shed carbon. In a endothermic gas filled furnace we would generally carborize at 1750 deg. The depth of penetration was determined by the material 1040, 8620 etc. and time at temp. The way of introducing carbon was simple. We simply plumbed in natural gas which burns and the byproduct is carbon. A carbon sensor on the furnace controlled a barrel valve to keep the carbon at a specific level. A product called condersol can be painted on a part to prevent carbon penetration into a area of part. Most large cities have several heat treating shops and a tour can be very informative. Keep in mind some steel such as 1018 will not respond well to case hardening and to prevent scaling you need a protective atmosphere. Thanks for the video. MH
Thankyou for your comment, I really appreciate getting the I sight of someone who did this method industrially.
If you are stuck for flat bar, try old leaf spring steel .Though it can't be guaranteed as 0.7% C., (eutectoid) ,it's superior for hardness, tensile, etc.tjere are colour charts available if you've no thermocouple or welders crayon for the heat treat.your quench method is fantastic .evens out the chill crystal structure.
* still will require normalizing. 250° /hr/cubic inch.
Great vid man.
It certainly would not be >0.7% C given that the specification for the two common spring steels is not >0.60%. Also contain around 2.0% Si. One grade also contains an amount of Cr (approx 0.50%). Be aware of so called spring steels being made in sub continent factories from old rail steels. NO Si content there.
Metallurgy and materials science was one of my favorite classes in college. (Aside from the lab reports of course) but we did so much cool stuff with different metals and plastics.
Great info. I noticed that your reference material had info from the Pennsylvania Rail Road's Altoona shops which is near my neck of the woods. Very interesting. They did a LOT of their own R&D with metallurgy to try and stay at the forefront of technology, but they held on to steam tech too long while most other RR's were converting to diesel-electric tech. The reason for this was that they worked hand in hand with the coal industry, and they didn't think using oil would pay off. They were wrong and eventually went bankrupt. Of course Air travel and trucking had a lot to do with it as well.
Very nicely done video! Thank you.
Lots of critics, you did a great job on a complicated subject in a home shop.
Thankyou
I've used brine quench in a running ultrasonic cleaner. The ultrasonic energy breaks the steam bubbles quite effectively but it also degasses the brine. The effect of salt in quench water is to reduce dissolved gases which nucleates boiling.
Also effective on pure water quench which has slightly better specific heat capacity.
Thanks for sharing artisan✌️
Well done man.
I really appreciate your videos
Thankyou
My shop instructor in the 80's recommended the used motor oil trick - I can't say for certain that it does or does not work, but even if it's a myth, it's one that has been around for a while.
This seems like it was outside your wheel house. Fascinating and an excellent video. I’ve been experimenting with a product called ‘Cherry Red’ out of the US and has worked great for case hardening clamps for my precision vice. I like the idea of using a forge for larger parts. My heat treat oven only goes to 6x6x4 inches.
Nice work!
A have home o traditional Oven, having a pretty high vent,,so I made a mix of backing soda and charcoal,all stuff in a sealed box, and kept it inside that oven for few hours under intense heat ,then from oven right into water.It Was amazing hard,I could scrach glass with...
Thank you well explained well done. 👍👍
Very well done and packed with well thought out comments. Since you have done a lot of the trial and error to find some of the better home shop techniques, how about putting together a video of the single best home technique with out so many "ifs and maybes" so we can concentrate on one procedure.
This comment is not meant to be critical in any way. This video was very informative and well presented. Just asking for a step by step procedure for dummies to follow. I will be watching for your next video no matter what it is. Thank you.
11:43 The use of oil or water must be made considering the steel alloy (Cr, Ni, V, etc) and not the carbon content. Alloy steels can be quenched in oil and non-alloyed steels must be quenched in water. What changes, between one type and another, is the hardenability.
Yes, but this video is not about alloy steel and I purposely exclude talking about it because as you correctly point out we then have to start talking about hardenability and TTT diagrams which I did not want to talk about in this video. This is just for plain carbon steel
I worked in the industry for many years and quenching a material like 4140 or 4340 was done in heated oil or a low temp salt brine. If we were induction hardening we used a heated glycol. A water quench is too much of a shock and would frequently lead to cracking. 1040 and maybe 4130 you could get away with a water quench. Regardless of what the final desired hardness was by the customer each material has a temperature at which its quenched at. The final hardness is determined by the secondary heating/tempering this is where the higher the tempering temp the lower the hardness. 4340 would usually soak at 90 minutes at 1525 deg. Get a 140-180 deg oil quench and have a as quenched hardness of RC (150kg) Rockwell of 55-60. It must have a secondary temper of at a min. 300 deg for 90 minutes or risk cracking from internal stress. When dealing with complex very expensive machined parts you only get one try to get it right.
Very useful. Congrtulations.
Great video! I was considering case hardening for some fixtures at my work, but I found a good spring steel, 5160, for a reasonable cost that worked great for our application. I have not tried heat treating it, because it has been doing great at the C25 it came with. It has not been too bad on tools. 5160 might be good for you or your viewers too. McMaster Carr description "Yield Strength: 97,000 psi
Hardness: Rockwell C25 (Hard)
Heat Treatable: Yes
Max. Hardness After Heat Treatment: Rockwell C63
Specifications Met: ASTM A689
5160 alloy steel handles repeated cycles of stress without breaking just like spring steel. It’s often used to make flat springs"
When your learning there's always teething problems. Back in the 80s I purchased a can of Hardite / barium chloride 20% and potassium ferric cyanide Great for case hardening.
Maby there's something in the book of armaments to consider , after all the Holy hand grenade was a winner ch2 v9.
Sodium carbonate is a good tip added to quench water .
interestingly, many early iron age Mediterranean artifacts appear to have been case hardened- even some Roman gladii
Just a thought on the used motor oil idea, I wonder if used diesel motor oil might be the key because of the amount of soot (carbon) that would be saturated in the oil compared to a much cleaner oil out of a gasoline engine.
Very educational!
Quick note: the depth theoretically grows as the square root of time, rather than being linear.
That might be true in an industrial setting, but I have not found that to be the case in the home workshop environment. Cheers
For a flat surface. A rod cases faster and so do outside corners.
@@artisanmakes I wasn't speaking to practical realities, only mentioning how the theory metallurgists use categorizes this is a "random walk" type behavior: you can get a linear fit over short times (ie. distances) but accepted mathematical models of it assert that there will always be diminishing returns as you keep going, due to the fact that carbon is diffusing outward as well as inward.
Old case hardening salts usually had sodium chloride and cyanide salts mixed in to aid in the dissolution of the carbon, but ofcourse those salts can sound a little terryfying, BUT by making the charcoal by carburizing something organic like leather in an oxygen free enviroment you can get carbon that already has very useful amounts of natural cyanide compounds in it. And the carbon doesnt all have to be carburized leather or some such, but something a third or a quarter of the whole carbon content. Additionally the rest doesnt have to be wood charcoal, it can be something else rich in organic carbon chains, such as sugar or flour. I don't know the exact chemistry behind it but the sodium chloride and cyanide apparently react together with the iron in such a way that the dissolvin of the carbon into the steel speeds up considerably
Very informative, thankyou.
Thank you for the time you spent making this educational video. Very interesting and well made. Subscribed for more!!!! :) Greeting from Greece
nice new video 😀
great very informative video
Super interesting !!! Thank you so much
Cheers
Well done...thank you
Outstanding video, Thanks.
Long ago I would put the steel in the carbonizing pack two or three times before quenching it for a deeper case. For a precision vise we would cycle the parts between an oven and a freezer several times to relieve stress.
Very interesting vid, thanks for sharing! I tried a method of case hardening I found over on the ‘Clickspring’ channel, don’t know if you found that one? He was making historically accurate tools for a project to re-create the Antikythera mechanism. Basic recipe had leather charcoal, flour and salt in it, I’d have to look up the proportions though. He did his in a sealed clay packet / crucible affair, I just used a metal box like you did and got good results on a small hammer head I made after about an hour in an electric kiln at about 900°. I didn’t get all the gal off the metal box before it went in the kiln, so the zinc oxidised and turned into a nice floaty white powder that went everywhere!
Quenching in water or oil is used to obtain different surface hardness. Also, for some steel grades, quenching is suitable only in a certain environment, quenching in an unsuitable environment leads to a shortage of hardness or internal defects of the workpiece. Blanks from low-carbon steel can be strengthened by the method of riveting.
Gday, thanks for taking the time to explain all this, it’s was very interesting, cheers
Cheers Matty
Most useful content. +1 I will likely experiment with this to case harden some linear rails for a rather large format 3D printer. I am aware, of course, that I will need to pay special attention to warping.
Great video! Thanks!
Good information, thanks
I greatly appreciate the info you've provided. In light of what you've presented, I was using too high of a temperature for far too long. Container was a lidded ceramic jar placed in a pottery kiln. Cycle time was on the order of 10 hours. 😯 Very haphazard.
Interesting, never thought about using a ceramic jar. There are charts online that will give you a good idea of case hardening times, for the vice, I case hardened it for around 10 hours and some times parts are case hardened for longer (in industry)
Clay flower pot with charcoal and old plate on top is just as efficient as a welded container, but much cheaper an reusable....
That's if you can still find a clay flower pot.
@@markfryer9880man. I can everywhere. Must be some gardening freaks around you
Tried the motor oil for trigger sets in airsoft guns, worked great. Just made sure I did any tuning/shaping of surfaces before I did the hardening. Made a huge difference in the life of the parts.
Glad to hear it
Good Video. You earned a thumbs up and a new sub.
Nice job.
I use Stainless foil and make a pouch I fill with part and charcoal. Bring to the "critical temperature" ..rapid quench in a "brinded" oil. (Salt).
Clean off the scale and draw back at half temp/time. 58/62 45c Rc. Every time !!!
P.S. 1550 deg for low carb. 1850 high carb.
Thanks for this it is very useful to me
Back in the 40's and 50's you could buy special case hardening powder. I can't remember exactly how it worked but I believe you packed the part in the powder and hested it in a forge to a soecified temp and time. I think it was some kind of high carbon content powder that would infuse the steel when heated, hardening it to a specific depth depending on how long you keep it in the forge and the amount of powder used. Tubalcain or MrPete222 has some excellent and very informative videos on the case hardening process and how to do it correctly and how to achieve the depth of harening that you want. I would reccomend checking out his videos. He is an infinite source of knowledge concerning everything to do with metalworking , machining and forging.
Interesting things to know
I have done my fair share of heat treatment case hardened or other you will never eliminate distortion. It is simply part of the game especially on intricate parts with variations of thickness such as your vice. I would say you were successful in the end. Quenching in water regardless of movement up or down or side to side the rate of change in temperature is extremely fast. Oil drops the rate of change more slowly but you would still experience distortion. I love the fact that you are not shy about trying new process and procedures keep up the good work.
Mike, I totally disagree with your statement. Countless times I used A2 tool steel and had it vacuumed heat treated. On critical pieces double or triple heat treatment would be in order. A2 would basically hold its size and hit the Rockwell required.
D2 tool steel ditto.
@@gordhildreth4630 That's fantastic I haven't had that experience myself but I'm glad you are able to old tight tolerances on parts post heat treatment. Myself if I'm looking for a flat square or tight tolerances work I grind the finish dimensions. I must be doing something wrong of course Air hardening steel is going to be much more stable. I can't say I have ever ran any parts that needed to be heat treated multiple times an annealing process perhaps more than once but never heat treatment cycles repeatedly.
try using a paste of charcoal with flour, let it dry and then use a normal thick clay jacket around everything, obviously just let everything air dry first and slowly rise the jacket's temp. i think clickspring did something like that
Some years algo i try this of hardering stell soft;and i use wood charcoal and Bariun carbonate..60..plus..40..hardering some knifs whit good end..and quench whit motor oil.
Great video, I won't be doing any of this, but it's a very interesting process nonetheless.
That's fair enough, but it is definitely an interesting topic. Cheers
CHARCOAL: When you were crushing the charcoal, I thought of a suggestion. You can get a jar of powdered charcoal, sold as an art supply. It’s very fine, like cornstarch, and might perform better or faster, given that there would be less air. Of course, anyone can crush charcoal more finely, but the powder is still pretty cheap, homogeneous, and ready to use.
I’m only speculating, but I also wonder if the charcoal source matters at all. It’s not likely, but some charcoals have different structures, and there might be a “best” charcoal. Bamboo has more silica in it, which might matter, for instance. If anyone has thoughts on this, I’d love to hear them.
very good video, thank you! - subscribed 👍
Form or drill a very small diameter hole in the box. This will allow pressure equalization without allowing oxygen in too quickly.
This should result in a more predictable opening than when mortar cracks under high internal pressure. The downside is lower CO concentration due to lower pressure while the box is unsealed.
A tip for making Charcoal powder more uniform would be to use a ball mill. But as those can be expensive you can make one cheaper by getting a rock tumbler/polisher and loading it with ball bearings.
Might have to ask a friend about broowing a ball tumbler
@@artisanmakes When you take the lid off, be gentle or the fine dust comes out like smoke and makes a real mess.
Charcoal is probably soft enough to process in a coffee grinder. Bob Adkins' warning about the fine dust applies to the coffee grinder as well as a ball mill. Use a good dust mask or you'll have black snot for a few days.
To get a precise temperature inside the casehardening box, you could use a thermocouple. A good one will have a probe that is resistent to the high temps inside the furnace, and the display should provide an accurate temp reading of the probe.
yes, that 's what was used in our belt furnaces in the thick Film dept. at the plant I worked for. Temps got up tp close to 1000 degrees Centigrade.
Thank you
works for me thankyou. I want to have a go at making a sledgehammer in wrought or mild steel and case hardening it for knocking in fence posts and the sodium carbonate and charcoal method looks ideal
Sounds like an awesome project. I think I read a while back about someone who did the same thing. Hope it works for you. Cheers
@@artisanmakes you nerver know I might get it on video. I usually get half way through something before I think....I could have filmed this ....