Home built Heat Treating Oven

[DanCom]

Nick,

You can do a sanity check with a piece of carbon steel and a magnet. Once the Curie point is reached the steel will become non-magnetic. This should be around 770°C. You can also set the controller to 660° and put some aluminum in a crucible. The alum should be just starting to melt.

A few points worth mentioning. In my experience with building ovens like this, the thin Kanthal will be susceptible to breakage. Once heated the first time it becomes very brittle. I would recommend at minimum 18 ga. 16 better, 14 better yet. Of course resistance (ohms per ft./m) drops significantly when moving to the heavier gauge. I have a Kanthal A1 spreadsheet on my blog page here. You may cover this a the another video but, make sure to double or triple back the wire on the leads exiting the kiln. This reduces the resistance and therefor reduces heat outside as well as makes for a better electrical connection. Also, the elements will sag when hot. Make sure they are stapled into the ledges. I will make a couple dozen from the Kanthal wire in a J shape and press them into the firebrick to secure the element. It would also not hurt to have a door switch that kills the power when you open the door. 220 VAC isn't fun to touch when extracting a hot blade. ;-)

Thanks for sharing!

Dan