heat treating ovens

C

cjd1980

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Sep 3, 2008
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I've been think about getting a heat treating oven was wondering what you guys would sugest I use mostly 5160 & 1095 for steels and only have 110 volts in the shop was also wondering if i can temper in them
thanks chris
 
You can temper in a heat treat oven, but it will take a while to return to low enough temps if the entire oven has been brought to a steady heat. That's going to leave your blades a bit vulnerable while you wait. I use a household oven closely watched with a second thermometer to check temp. A good number of folks use a large toaster oven with a brick placed in to increase thermal mass and a second in-oven thermometer to check temp.

As for recommendations, since you only have 110V available, unless you can get 220V wired in, you will be limited in choices. I believe Evenheat has a model running on 110. Mostly, folks will tell you it will take a while to reach critical temperatures, but will do pretty well for 1095.

--nathan
 
patriqq said:
Nathan:



could you explain what that means?

thanks
Click to expand...

I means while you wait for the oven to cool down your knives are in a state where anything could break them. as ling as you are very careful it shouldn't be a problem. You just have to put them somewhere out of the way, as they are as brittle as glass after quench.
 
1095 is very brittle after quenching. I've heard of it just cracking while laying on a table, although its hasnt happened to the ones (about 4) that I've done. If mine cracked, it was in the quench. However, if you drop one, let nearly anything fall on one, or place a heavy object on top of one, you definately run the risk of cracking the blade if it hasnt been tempered. In the cases of dropping the blade or dropping something on it, cracking is almost assured in my experience.
 
I use a Sugar Creek big knife kiln. It runs on 220v, but they make a smaller one that is 110v. The good thing is that at half the price of an evenheat or a paragon, you can have a 220v hookup installed with the money you save. If you could get the 220v, I think it would definitely be worth it. I have been very happy with mine. Here is their web site.

http://www.sugarcreekind.com/kilns-knife-kilns-c-273_312.html
 
Generally do a first temper on the low side in a toaster oven then do the later
precise tempers in my Evenheat after it's come down to a usable temperature.
The first temper mainly protects the steel while waiting for the controlled tempers.
 
Paragon and Sugar Creek are the only 110V models I know of for makers. Unless you get a digital controller on the sugar creek it will be very difficult to temper with. You can also get a glass annealing kiln or other cone 10 kiln that will run 110V, but you'll be much more limiting in blade size.

You can temper just fine in a toaster oven as long as you monitor the temp and know how it swings. You could get a $50 controller and turn a cheapo toaster oven into a pretty good machine. Best to let it even out a bit and even throw something like a chunk of aluminum or steel into it to help it equalize.
 
I bought a toaster oven on close out and then found a digital them. for it. Have not had a chance to use it much yet but it sure seems to work good so far. I think I have about 30 dollars invested so far. I have even thought about getting one of those event timers that plug into the socket and then plug the toaster into it, then I do not have to even be there to watch it. Just set the timer and go about my business of doing other things.
 
The steel can also "crack" and not be visible to your eyes :eek: If you have the $$, buy two kilns! otherwise, find a really large toaster over or your wife's kitchen oven to do temper #1. After that, the 2nd, 3rd, can be done either a day apart or 10 days apart, etc etc.

I'm guessing tool steels like D2 (i think) could be tempered in the same kiln as the first temper is rather high or they lol are all kind of high in temperature.
 
how do you suport the knives while they are in the oven is there a rack that you can buy or make
 
You can cut soft firebrick to just about any shape with a butter knife or hacksaw. You can cut grooves in a slice of firebrick for a quick and easy solution.
 
In my oven, I simply took a piece of soft refractory brick, cut it down so it has a stable base with a thin horizontal upright with a groove in it to hold the blade/foil packet on it's edge. It's an oversized groove so as to not insulate the steel, just support it a bit if necessary. Most of my blades balance well on their spine anyhow. I always place the steel where the blade is completely in free air for the most even heating and the upright/groove is supporting the steel at the handle area. Works great and was free as I had an extra brick laying around after completing the oven.

--nathan
 
Foil is used for your stainless steels that require long soaks at extreme temperatures to prevent de-carb. from oxygen exposure. Also, it is used for your air hardening/plate quenched steels (D2, A2, and most stainless steels) which are susceptable to decarb as well from air exposure at high temps. 1095 and 5160 are both oil quenching steels with lower critical temps (1535F for 5160 and 1475 for 1095) and relatively short soaks at temp, so foil will actually hinder you, especially with the speed of quench that 1095 requires.

--nathan
 
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