Can i get a proper heat treat without kiln

BlueBird

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.
 
Gene Kimmi said:
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.
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I agree with Gene. But you might consider 1075 or 1080 or 1084 steel instead of 80crv2.
 
BlueBird said:
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.
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I'll suggest checking out Knife Steel Nerds. Larrin just did an article that addresses this very question (I think he used 80CRV2)
knifesteelnerds.com

How to Heat Treat Knife Steel in a Forge - Knife Steel Nerds

Can a metallurgist with no experience heat treating with a forge do it successfully on the first try? With seven different steels?
knifesteelnerds.com knifesteelnerds.com
 
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.
 
billyO said:
Out of curiosity, Gene, do you know if ATP-641 anti-scale treatment helps with this?
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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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