tempering oven

Kevin McGovern

Kevin McGovern

Joined
Jul 31, 2015
Messages
3,118
So what do you guys do about tempering? I have been using a toaster oven that i have a TC in, but it swings wildly in temperature. Granted, its a cheap small oven, but it's a pain to constantly be checking and adjusting it. My main heat treat oven takes way too long to cool off to use that. It seems like my kitchen oven holds temp much better, but I would prefer to temper in the shop. I'm looking for a low cost solution if possible, since it is a convenience thing for me to stay out of the kitchen. I am thinking of wrapping my toaster oven in innswool since i have some left over. Maybe that will help it hold temp? Maybe invest in a better toaster oven if anyone out there is using something that they can recommend as accurate and stable. (accurate as in will hold a temp, not necessarily the temp it is showing, I know i will need to monitor with my TC thermometer and compensate). Thanks.
 
If you are looking for a very cheap solution to this, cover the blade to shield it from direct radiation and just stick larger pieces of steel inside the toaster oven with your knife. The other pieces will act as a heat sink which will slow down the rate of temperature change of the air inside.
 
I bought a toaster oven with digital control on sale new for $75.00. I tested it with my thermocouple, and it was accurate +/- 10f once at temp. I now use an oven gifted from a relative who did kitchen renos. It's in my shop, so I don't have to use the oven in the kitchen. For the toaster oven, a 1/4" thick, 2" wide 10" long piece of mild steel on the rack acts as a heat sink, and minimizes fluctuations.
 
I can get my oven from 1500 to 600 in about 15 minutes by putting a big block of aluminum in it (with power off).

Adding digital control to a toaster oven is painless if you are ok with electronics. You need a controller, probe, SSR and connecting hardware.
 
I put some ceramic tiles in mine to put the knife on and check it with a pyrometer/thermocouple. It stays very even inside.
 
Ok, so after browsing around and thinking I want to get better and consistent results I just purchased everything on ebay for $50 to turn my toaster oven into a PID controlled oven. I didn't realize I could get all the parts that cheap, and as it turns I found a seller that has everything in one bundle with free shipping. Pretty good deal I think. Should get in in time for my next blade.
 
Yes, it should'nt be that big of a deal, since I built my PID controlled HT oven. I just have knives to finish before I start on another build project. The hardest part of setting up a PID is figuring out the programming. Once you do, it's pretty sweet.
 
PID control on a toaster oven is the way to go for sure. My toaster oven holds ±1ºF pretty constant once he settles on temp.

Ken H>
 
you referred to a piece of equipment as a "he"? Tools are loud, take all your money and we love them. Therefore they should always be referred to as "she". Just a heads up.
 
Why don't you just let your oven cool?
You can use your kitchen oven for a quick 350 snap temper if you're concerned about something weird happening, and by the time that's done you can move to the technical oven for a controlled second temper.
 
kdogmcg said:
I thought about that, but an hour after I turned it off, with the door open, it was still 800°F
Click to expand...

Goes to show you how well insulated and efficient those technical ovens are. At least here in Ontario, Canada where electricity rates are ridiculous, that would save a lot of money. I should invest in one and use it as a regular oven with which to cook.

All praise aside, you can load up the oven with scrap metal one you are done. It will absorb the residual energy. Take it out, quench and repeat.
 
Kosa_PL said:
I'm using this small badass :)
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That enclosure is bad ass. I think I am going to try something of that nature for mine.My parts have already left PA and are in OH. supposed to be in friday... :thumbup: :thumbup:If I quit taking on other projects, I might actually get some knives made, however all of the projects are going to give me better quality sooooo.

Where did you find that enclosure?
 
duurza said:
Goes to show you how well insulated and efficient those technical ovens are. At least here in Ontario, Canada where electricity rates are ridiculous, that would save a lot of money. I should invest in one and use it as a regular oven with which to cook.

All praise aside, you can load up the oven with scrap metal one you are done. It will absorb the residual energy. Take it out, quench and repeat.
Click to expand...
Thanks. I built it myself.
 
kdogmcg said:
you referred to a piece of equipment as a "he"? Tools are loud, take all your money and we love them. Therefore they should always be referred to as "she". Just a heads up.
Click to expand...

Kevin, "he" was a typo for sure. When I read your post this morning I went back thru the posts to see who was silly enough to refer to tools as "he"..... darn, it was ME!!! :grumpy:

Ken H>
 
i use a toaster oven. i found the largest baking pan that would fit, filled the pan with play sand. bury the blades and temps stay pretty constant. i use oven mode, so only the bottom heaters are on.
 
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