Tempering Oven

Jonathans

Jonathans

Joined
Jan 9, 2008
Messages
588
Hi all,
I am looking at picking up an oven for tempering. Wifey no likey steel in the kitchen until it's finished.
The oven I'm looking at is 23x23x15. Interior is 18.75 x 13.75 x13. Kinda big for a single 18" blade and I probably won't ever do more than a couple at a time, as i am a hobbiest. Before I pull the trigger on this, is there a better way to go? I plan to get an Evenheat in the future, but see many shops with both a HT kiln and a temper oven. What's the best eay to go?
 
For the wifey thing = learn to remove ALL grease , dirt ,etc before thinking about kitchen HT !

Many use a toaster-oven , even a used one picked up at a garage sale. Put brick or such in the bottom to get more even heating. Check with a good thermometer. That's all you need .
 
I have read that many do not like to use their heat treatment oven for tempering. For me it would be nice if I could use an evenheat oven to do my tempering as well.
I could just set it and work on other things not have to worry about checking as often. As long as I could trust the temperature was stable.

is the popular consensus that you need a tempering oven as well as a heat treatment oven or forge as well?

Thanks.
 
The "popular" consensus is all over the place. Since it's so cheap to setup a toaster oven with PID controller for tempering, that's what I did. The only time I use my EvenHeat oven for tempering is folder backsprings that need up around 1100ºF for lower Rc level.

Either way works - BUT, if you do use a toaster oven be SURE to check temperature with a good thermometer and allow time for oven to even out in heat. Some of the toaster oven's temperature control isn't very good and will allow ±25ºF (maybe even 50!!) temperature swings which is not good for tempering. The Even heat is more stable than that. With PID control I can hold ±1ºF pretty much all the time with a brick in oven to provide additional mass.

Ken H>
 
I think the reason (at least in my experience) is that the kiln is not good at controlling temperatures at low levels. The size of the coils makes it great to ramp up to 1000F quickly but when you watch it try to hold a temperature at a lower temp like 400F you see it struggling because it doesn't have to stay on long at all and it can sail past 400F very quickly. If you're not worried about that then it should be fine but if you want precise control I think guys tend to get a smaller oven cheap and retro fit a pid controller.
 
In case you have a hard time finding the stickies for this, the main tempering oven PID thread is:

http://www.bladeforums.com/forums/showthread.php/599423-Pid-Toaster-Oven-Conversion?highlight=PID

Stacy gives a LOTS of good info there. One thing I might add is on selecting the PID controller, be sure it's got a SSR output. That will make everything a LOTS easier to wire up. The PID ebay links are broken, so you might just do a search for REX-C100 (but that one is C only, no F available). This "100-240V Digital PID Temperature Controller + max.40A SSR" will also turn up several PID controllers on ebay. I have used Auber PID controllers which I like - they're around $40 or so for bare controller, while the PIDs above are in the $25 range and that includes SSR and TC.

This thread has a good wiring diagram for wiring a SSR type PID to a toaster oven: http://www.bladeforums.com/forums/showthread.php/1002319-PID-Controlled-Tempering-Oven-Diagram

Good luck - Stacy has some good info in those threads above.
 
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