Can i get a proper heat treat without kiln

BlueBird

Member
Hi guys,

So my first batch of aeb-l knife are out for heat treat but i would like to make some blades in 80crv2 and HT by myself. With my CNC and my new 2x72 and bunch of other stuff, my budget is limited and i cant afford a kiln for the moment. So i was thinking buying a small propane forge with a thermometer.

So my question is, can i do proper heat treat with a setup like that ? I would like to go with 80crv2 because from what i read, its pretty easy to HT.

Thanks!
 
With a proper set up, I believe you can get a good heat treat on simple steels. When i was heat treating in my forge, I used a square tube for a baffle and had a thermocouple in it. I was able to hold temperature within 5 - 10 degrees. It took some experimenting getting the burners set just right, using a baffle over the air intake of them, and setting the propane pressure just right, but it worked. You'll need a toaster oven or kitchen oven to do the tempering.
 
With a proper set up, I believe you can get a good heat treat on simple steels. When i was heat treating in my forge, I used a square tube for a baffle and had a thermocouple in it. I was able to hold temperature within 5 - 10 degrees. It took some experimenting getting the burners set just right, using a baffle over the air intake of them, and setting the propane pressure just right, but it worked. You'll need a toaster oven or kitchen oven to do the tempering.
I agree with Gene. But you might consider 1075 or 1080 or 1084 steel instead of 80crv2.
 
So my question is, can i do proper heat treat with a setup like that ? I would like to go with 80crv2 because from what i read, its pretty easy to HT.
I'll suggest checking out Knife Steel Nerds. Larrin just did an article that addresses this very question (I think he used 80CRV2)
 
One thing with 80CRV, you will get a lot of decarb with it. If using a file to see if it hardened, you'll have to file a little deeper than other steels.
 
Out of curiosity, Gene, do you know if ATP-641 anti-scale treatment helps with this?
I can’t honestly say, as I’ve never used it. Since I do so much stainless, I use foil on anything I don’t want to decarb. I put all my damascus in foil when I normalize and thermal cycle it, then take it out to austenitize and quench.
 
I've been using the setup Gene mentioned - propane + baffle + thermocouple on 1084, 80CRv2, 26C3. ATP 641 seems to help decarb.
I'd recommend modifying a table top oven so it has digital temp control (a simple conversion). As built oven controls aren't worth a sheeet.
 
Unfortunately I think the short answer is no. You may get a decent heat treat the odd time but its not consistent or repeatable. Alot of variables at play. If you're not selling them then I wouldn't worry but if you are I would outsource until you can afford a kiln and a proper hardness tester. I know it sucks and its expensive. Nothing worse than spending hours on a knife only to find out its not heat treated properly. I think there are ways to help improve consistency but ultimately time is money and I just believe you're time is better spent improving your knives, processes etc. Instead. Obviously just my opinion, best of luck. Would love to see some of your work.
 
I have made at least 40 knives heat treating myself, with simple mini forge I built (copied). I only do 1084 and have had at least 10 tested locally between 59-61 with +/- 1. Stainless is treated at shop that tests my 1084, can't afford the equipment for stainless hardening yet. You can definitely heat treat some steels with propane forge without a thermometer, use a magnet and eventually your eye will know when ready to dip in oil (Parks 50 recommended/sold here). Luckily I have a known national shop near me to help with testing and this forum.
 
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I agree about using 1084 or similar steel if you are going to heat treat without a kiln. I started that way and still receiving good feedback on the blades.
 
The late John White used to do all of his big knives with hamons in a smaller version of a Fogg "drum" forge made from like a 20 gallon propane tank. He was able to hold the temp VERY tight. He would actually weld a mild steel "handle" to the end of the tang so that he could suspend the blade in mid air in the center of the forge. Not a simple setup, but one where most of the "cost" would be your time, effort and frustration. ;)
 
Many will say you can't, but I disagree. If you use 1084 and get your forge temp regulated I think you can.

I did a lot of testing and finally got my set up to produce consistent results. I do have a heat treat oven on
order though. I want to branch out to stainless and I don't see that working in a forge.

I do have my own hardness tester and my blades come out to 59 - 61 HRC every time.

Here's a pic of some 1084 I heat treated in my forge.
 

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The bottom line is that there are simpler steels that are more forgiving in the austenizing department, such as the `10XX steels, but that said, there is no such thing as too much temperature control for heat treating a blade.

Doug
 
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