Charcoal

Rick Otts

Well-Known Member
Now I seen on You tube guys using charcoal to heat treat.Now I know this isnt a real good method but I figured my 1st couple knifes it would work.I am going too use 1084 so I would heat it until its non magnetic the quench in Canola oil.Then temper twice so how does this sound?
 
Almost every time I watch a Youtube video dealing with knife heat treating these days I want to weep for the state of knowledge in our craft, however, the charcoal thing isn’t that bad. In fact, coal or charcoal can do a pretty darn nice job with a steel like 1084. Make a quick tunnel over the fire by stacking a couple of firebrick over a couple set on edge, then heat the fire until you have a nice blue flame coming out of either end of the tunnel and you will not only have some pretty good heat control, you will also have a nice reducing atmosphere that will keep your blade fairly clean.

Heat that canola to 130F and it will give better performance. Heat the blade to nonmagnetic, (but keep practicing until you can recognize the proper color of decalescence and it can be even better) then quench. Get it into the kitchen oven, set from 350F to 400F, right away to avoid possible cracking or warping.
 
Rick, did you ever try this? If so how'd it go for you.

I just tried on about 4 knives. I'm saving what precious little propane I have for something else.

If I do it this way again I'm going to add firebrick around (and under), use a lot more wood to get a bigger base of coals, figure out a way to get a digital thermometer in there without burning the wires, and install some kind air flow.

The thing I was trying for was to get the fire down to coals, where there's no yellow flame, and then blow on the fire to heat the coals and the knife. I thought yellow flame was indication of oxygen, so I thought I needed just coals. I didn't know about getting blue flame.
 
I haven't done very many knives, like maybe five total, but I've done all but the most recent one this way with mixed results. These were all 1095

I used a hair dryer to heat the coals and just dropped my knives in the coals and used a magnet to check for nonmagnetic, and eye balled the color. I had one knife that turned out well this way. The others were so so. I also had quite a bit of clean up to do afterwards.

I wish I had thought of using the firebrick. It sounds like that would make a big difference.

Since then I've built a small forge to heat treat out of a paint can and I'm now working on a larger forge for both heat treat and forging.
 
I am sure you guys already know this but the OCD part of me just has to say it anyway. If you are using charcoal make sure it is the lump charcoal and not the briquettes. The briquettes have binders in them and while you can get by with it the lump charcoal is better. I have hardened many knives this way using a propane forge but the process is the same. Follow what KC said and you will be happy with the results. Try and notice the decalescence if you can it may take a few times to be sure.
 
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