PID Controlled Tempering Ovens

CDHumiston

KNIFE MAKER
Does anyone know of a source to buy a nice PID controlled Tempering Oven?

I know people make these at home and I've watched a lot of YouTube videos.
Bottom line is I don't want to make one as it looks like a lot of trouble.

I have a Paragon heat treat oven and it just takes too long to cool from 1950 to 300 degrees!

I guess I could put my blades in the freezer while I wait...

Has anyone tried out those $500 range 1/2 size ovens? I've been looking at this one.

Thoughts? Experience?

https://www.amazon.com/dp/B01K3L61L...olid=2UFDW4OK99MDQ&psc=1&ref_=lv_ov_lig_dp_it
 
The problem with the one you linked to is the problem with all of them...temperature swing. the people building them with PIDs are also gutting them and insulating them with kao wool or some other refractory insulation.
I've looked into building one,I've got a decent toaster oven with convection and while it may seem like a pain in the a--. the results seem good if done right. I plan on doing mine probably around April, just don't have the time now.
 
The problem with the one you linked to is the problem with all of them...temperature swing. the people building them with PIDs are also gutting them and insulating them with kao wool or some other refractory insulation.
I've looked into building one,I've got a decent toaster oven with convection and while it may seem like a pain in the a--. the results seem good if done right. I plan on doing mine probably around April, just don't have the time now.

This is supposed to be super stable. The heating elements never turn off like a conventional toaster oven. Goes from 50-500 degrees and can be programmed to stay on for 99 hours, not that you would ever need that!

http://www.amazon.com/dp/B0B25STXV2...colid=2H0XHL9QUIXPO&ref_=lv_ov_lig_dp_it&th=1
 
Well......I don't know. $314.00 is a lot of scratch to drop on that hoping and not knowing FOR SURE that it will perform like you want it to and the interior looks kind of small.
when on the other hand you could build one with a PID and be pretty much assured it will work. but you could try it and if it doesn't work like you want just give it to your wife. :D
 
Well......I don't know. $314.00 is a lot of scratch to drop on that hoping and not knowing FOR SURE that it will perform like you want it to and the interior looks kind of small.
when on the other hand you could build one with a PID and be pretty much assured it will work. but you could try it and if it doesn't work like you want just give it to your wife. :D

Amazon has a pretty good 30-day return policy. I could just monitor temps and make sure it's stable...I just don't have the time or patience to build one. Too bad no knife makers sell them already made!

12x14x9.5 interior dimensions
 
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Try a counter top roaster and fill it with oil. If you go that route you will need to make a rack that will hold your blades. The mass provided by the oil will dampen the temperature swings. This should serve unless you are using high alloy steels. For safety, keep a fires extinguisher handy that if rated for oil fires plus keep the lid handy

Doug
 
I wouldn't rely on standard oven temperature controllers. Tempering temperatures need to be held to much closer tolerances than conventional oven controllers offer.
I converted an old pawn shop table top oven & added a general use, PID controller (plug&play) from Aubers.
Not hard to convert the oven. The controller is simply an on/off switch that is set for the target temp, and adjusts for the rate of heat change in the oven. After adding insulation mine holds within 5-10 degrees of target temp.
In total, I probably have $200 in it.
 
One note programming a PID controller for an oven - it can be a challenge getting the settings right for a oven's unique heat loss. Fortunately some PIDs have a self programming feature that helps a lot with the set up.
 
Try a counter top roaster and fill it with oil. If you go that route you will need to make a rack that will hold your blades. The mass provided by the oil will dampen the temperature swings. This should serve unless you are using high alloy steels. For safety, keep a fires extinguisher handy that if rated for oil fires plus keep the lid handy

Doug

Is this good for stainless steel? It's pretty much all I use.
 
I wouldn't rely on standard oven temperature controllers. Tempering temperatures need to be held to much closer tolerances than conventional oven controllers offer.
I converted an old pawn shop table top oven & added a general use, PID controller (plug&play) from Aubers.
Not hard to convert the oven. The controller is simply an on/off switch that is set for the target temp, and adjusts for the rate of heat change in the oven. After adding insulation mine holds within 5-10 degrees of target temp.
In total, I probably have $200 in it.

I assume you drill a hole in the oven somewhere to insert the probe and then let the PID do its thing.
 
I assume you drill a hole in the oven somewhere to insert the probe and then let the PID do its thing.
That's correct.
And then disconnect the wires going to the oven's temperature sensor and connect new wires to the heating elements, those new wires plug into the back of the controller I mentioned. The PID controller then takes over energizing the heating coils.
 
I actually use my kitchen oven. I put the blades into sand in a 9x13 tray and set the temp to 15 degrees lower than I want (My oven overshoots a bit). I have a stand along digital thermometer, so I monitor the temp of the oven during the process periodically. I can adjust the oven temp as needed.
 
If you want to save a few bucks while simplifying things quite a bit, they do make "plug and play" temp controllers like this one:


Just plug your oven into the outlet, insert the TC (you'll probably want to drill a hole somewhere around the middle side or rear of the oven, and you're mostly good to go. Might not hurt to add some thermal mass and/or high temp insulation to help lower temp swing.

You'll also need an analog style oven if you want to avoid bypassing any digital controller that might reset when the plug-in controller cuts the power to the oven.
 
BTW, if you go with a controller similar to the one I posted, just make sure it can handle the wattage on your oven. Most small toaster ovens are probably only 1000 to 1100W or so, but if it runs a little higher than that, there are similar controllers out there with higher capacity.
 
C D, I would say that the roaster filled with oil will not work with stainless steel unless you work with an alloy that will temper below 450°. Pushing over that you would be risking the oil igniting so check the flash point. One other thing. If you do try it do it outside your workshop or house and under no circumstances have water standing by to fight a potential fire from the roaster or you may have the burning oil explode all over the place. Dry fire extinguishers only.

Doug
 
C D, I would say that the roaster filled with oil will not work with stainless steel unless you work with an alloy that will temper below 450°. Pushing over that you would be risking the oil igniting so check the flash point. One other thing. If you do try it do it outside your workshop or house and under no circumstances have water standing by to fight a potential fire from the roaster or you may have the burning oil explode all over the place. Dry fire extinguishers only.

Doug

One of the reasons I shy away from carbon steel is the mess and storage of heat treat oils. I think I'll stick with a toaster oven or 1/2 size oven. Thanks for all the info though!
 
If you want to save a few bucks while simplifying things quite a bit, they do make "plug and play" temp controllers like this one:


Just plug your oven into the outlet, insert the TC (you'll probably want to drill a hole somewhere around the middle side or rear of the oven, and you're mostly good to go. Might not hurt to add some thermal mass and/or high temp insulation to help lower temp swing.

You'll also need an analog style oven if you want to avoid bypassing any digital controller that might reset when the plug-in controller cuts the power to the oven.

Looks like a good option, but this one only covers up to 248 degrees and I need at least 300 degree control.
  • Temperature Control Range:-50~120°C / -58~248°F
 
That's a nifty oven, looks like the max temp and % tolerance would be good.
Only downside I see is price, and it's apparently from China. The owners manual may take a bit of interpreting.
 
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