Newbie question on ovens

[Willie71]

I went through the stickies on the home made heat treat ovens and converted toaster ovens. Are these meant for just tempering temperatures or can they do full 1600f heat treatments/soaks/normalizing? I have access to many used ovens and will take up shop space if they can be used for more than just tempering. If I can only temper, then I will make a propane PID forge and use a smaller tempering oven more the size of a toaster oven.

 

[Patrickknives]

You need a full size oven for heat treat (reach 1400+) such as the paragon. The home made oven usually do the full heat treat 1600f heat treatments/soaks/normalizing. You can only temper in a toaster oven (250 - 400).

 

[Willie71]

Thank you. That helps a lot. I have really good temp control in my convection kitchen oven, and since I am the cook in my house, I have been tempering in it with a quality oven thermometer. I will not need to add a second oven, and with a PID forge, I can heat treat with that once I get it set up.

 

[Bo T]

A number of makers use a converted ceramic kiln for the normalizing, quenching part of the heat treatment. Many of them hook up a PID controller (often programmable) for regulating the temperature. The toaster ovens are for tempering only as they can only reach @ 500 F. Some have built an oven like the paragon that should be able to reach temperatures @ 2100 - 2200 F.

 

[Stacy E. Apelt - Bladesmith]

Willie,
The ovens we are talking about for HT are electric kilns made especially for knife HT. A convection oven won't work. Home kitchen ovens, convection ovens, and converted toaster ovens are used for tempering, as the range only needs to be 350-450F for most tempering requirements.

For HT, you need 1400-1600F in a well regulated electric kiln or gas forge for carbon steel, and for stainless steel you need 1850-2100F in a well built kiln with a multi-program ramp/hold controller.

 

[Willie71]

Thank you. I meant I can temper, and have tempered with my kitchen oven. So far the heat treating has been a forced air fireplace which acts like a blast furnace when the ash tray is out to get the metal past magnetic. I am working on some more sophisticated equipment and have 2 forges in the works, a small fuel efficient one for less than 10" blades, and a larger one for up to 18" pieces. From what I am reading an oven can't be converted to a heat treat oven and a specialty built oven is needed.

Stacy, helpful as always. Just as an FYI, including the temp range in the plans would help us new guys.