Toaster oven for tempering?

DiverTexas

Well-Known Member
The wife was less than thrilled when I told her my plans to use the oven for tempering my blades after HT.
I seem to recall someone saying that you could use a toaster oven for tempering small and medium blades.
Has anyone ever tried this or heard of it, or was it just my wishfull thinking?
 

DiverTexas

Well-Known Member
I have a very accurate Fluke laser thermometer.
Would that work if I opened the door momentarily and took a reading on the blade?
 

Tod Lowe

Well-Known Member
You can just by a oven thermometer and leave it in there. They are pretty cheap. My toaster oven is off by 75 degrees:eek: so you really cant trust the dial.
 

DiverTexas

Well-Known Member
Thanks Jeff and Shank, I'll just go with the oven thermometer.
Surely she won't notice it's missing.
 

JAWilliams

KNIFEMAKER
I use a toaster oven all the time,but i use a good oven thermometer to make sure the temp is right.
That is what I use and Jeff is right. Get a good oven thermometer. I got the idea from Wayne Goddards video. It is what he uses. the tmperature is more steady that you kitchen oven.
 

Wayne Coe

Forum Owner - Moderator
I used a toaster oven for several years, before I got a convection oven for the shop. I think that it is a good idea to put a layer or two of Inswool around the sides, top and bottom of the toaster oven. It will help keep the heat inside and more uniform. I really like the convection oven because it keeps the temprature in the oven more uniform and more even heating. It is something that you can not afford to purchase just for tempering. I got mine because we had purchased all of the appliances for our new home and I asked the dealer if he had a convection oven that they had taken out of a house. The only one he had was a Kitchen Aide combination Convection MicroWave and he gave it to me. New it cost about $2,500.00. It never hurts to ask.2thumbs Now I can temper, anneal and heat my coffee. The oven had been in a TV station and the new chef for their morning show didn't like the Kitchen Aide and wanted a Thurmadore. I just love these guys who like to spend other people's money.
 

DiverTexas

Well-Known Member
Lots of good info as always from you guys, much appreciated.

I just got back from buying one and I think Wayne may have answered my next question before I had a chance to ask it.
I got a Black and Decker digital convection oven.
I was going to ask if using the convection option might more evenly heat the blade(s) during the tempering. From what I'm reading, it appears so.

Another question though.
Is it ok to place the blades directly on the rack during tempering?
Should they be turned half way through the process or maybe just turned on the second tempering?

This is the one I bought.
Thanks in advance for any input you might have.

 

Wayne Coe

Forum Owner - Moderator
Looks like a good move Russell, More expensive than a toaster oven at the thrift store but a better unit.

I don't think that you need to be turning the blades. The convection moves the air around to, hopefully keep a uniform heat through out the oven. I would "borrow" you wife's thermometer to check the temperature throughout the cycling. The thermometers are cheap enough that you should probably keep one in there anyway. I think that laying the blades on the rack should be just fine, after all, if the oven is at the temperature that you need and the racks have been in there all the time they will be hot too and would not be a heat sink. The wires are small enough that they should not cause uneven heating. Check it out and let us know! If you do need stand offs I do have ceramic pieces for that for sale at $1.00 each plus shipping.
 

Mike Barton

Well-Known Member
When you get the money you could go over the top and run it with a PID controller like this:



That's a large piece of 1/2" aluminum plate in it for a heat stabilizer with stainless pins. It holds temperature to +/-1 degree F of setpoint after the initial autotune and warm up. Stacy put the original control plans over on BF. If you want to do it this way PM me and I can put together a print for the controller circuitry and send it to you.
 

DiverTexas

Well-Known Member
Thank you Wayne, I appreciate you sharing your knowledge with me.
I have tons of questions and have found that the folks here are always willing to lend a hand and share their knowledge.
I did get a thermometer when I bought the oven.
The wife has put up with me for 30+ years and decided she was worth the $9 investment.

I'm going to try my hand at heat treating the blades in the morning and tempering them during the day.
My plans are to HT and then allow them to cool to room temperature after the quench in Canola oil.
I planned on two one hour cycles at 450 with a cooling to room temperature in between.
If you or anyone else thinks there is a better scenario, please let me know and I will definitely listen.
Thanks again to all the dogs out there that have helped me to this point.
Another good reason to be a part of this forum.
You guys rock.

Russell
 

DiverTexas

Well-Known Member
Wow, Mike you posted that while my slow old hands were typing.
Give me a second and you will have a PM incoming.
Thank you much.
 

JAWilliams

KNIFEMAKER
Lots of good info as always from you guys, much appreciated.

I just got back from buying one and I think Wayne may have answered my next question before I had a chance to ask it.
I got a Black and Decker digital convection oven.
I was going to ask if using the convection option might more evenly heat the blade(s) during the tempering. From what I'm reading, it appears so.

Another question though.
Is it ok to place the blades directly on the rack during tempering?
Should they be turned half way through the process or maybe just turned on the second tempering?

This is the one I bought.
Thanks in advance for any input you might have.

Where did you get it?
 

Tod Lowe

Well-Known Member
When you get the money you could go over the top and run it with a PID controller like this:



That's a large piece of 1/2" aluminum plate in it for a heat stabilizer with stainless pins. It holds temperature to +/-1 degree F of setpoint after the initial autotune and warm up. Stacy put the original control plans over on BF. If you want to do it this way PM me and I can put together a print for the controller circuitry and send it to you.
Great job Mike. You don't mess around.
That table looks nice and stout also. Nice.
 

Mike Barton

Well-Known Member
Great job Mike. You don't mess around.
That table looks nice and stout also. Nice.
Tod,

Thanks. The table was built when I built my main heat treat oven table to use up all the materials. It was put together along the lines of my other work benches. If you can't beat on it with a sledge hammer it's just not a work table :eek::D
 

Sampson knifeworks

Well-Known Member
Toaster Tempering

Hi,
I have a older toastmaster convection oven that I have used for many years for my tempering. I like to use a rack to hold my blades edge up in my oven, I made mine by slotting a soft fire brick to hold 5-6 blades at a time. I would think if you lay your blades flat on the rack they would heat evenly through without turning them over, as long as your temp is right and you hold that temp for the proper time.
Take care,
Clint Sampson
Sampson Knifeworks
2thumbs
 

EdCaffreyMS

"The Montana Bladesmith"
I've kept an eye on this thread, and hesitated to respond because my opinion on toaster ovens for tempering isn't favorable. The reason that I'm not a fan of toaster ovens for tempering is the wide "swings" that often occur when the element(s) kick on or off. When I first tried using a toaster oven for tempering I thought it was going to work out well.... I tested the oven with an oven thermometer, and it was about 50F off, so I compensated for that, then, after tempering several blades, I noticed that the tempering colors were different than what I was used to seeing. I would have never known what was going on had I not noticed the tempering oxide color difference from other methods I'd used. It took me a while to figure out what was happening, but eventually I discovered that when the oven cycled (when the elements kicked on or off) there was between 75 to 100 degree rise or fall in the temp from the setpoint, that would last 3-5 minutes. I would not have figured it out, had I not just stood there and watched the oven thermometer.....every time I checked it previously, the thermometer was right were it should have been....but when I heard the "click" of the elements turning on, the oven would always spike up about 100 degrees above the setpoint, and then fall about 50F below the setpoint before the elements would kick on again.
It might have been a faulty thermostat in the oven, but I tried a couple of other ovens and found the same thing happening.

Maybe I'm just too anal about having control over the process, but my experiences were not good with a toaster oven, and now the last one I purchased is relegated to heating kydex in the finish shop. Those are just my experiences. If you feel like it's working for you, then by all means use it, but it's just not precise enough for me.
 
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