Wednesday, January 22, 2014


It's been a while since I sat down and actually did some knife work as I have been working on the 2 x 72" belt grinder. Now that the grinder is done I got back to some heat treating today.

I made a foil pouch from 0.002" 304 stainless steel and add a tiny piece of tissue paper.

Then I fold and crimp the edges to make a seal. Two folds all the way around.

While I am preparing the pouch, the heat treatment oven is warming up. Once it reaches 1050°C, I open the door and quickly slip the pouch in.

As I don't have a stand, I use a piece is fire brick with the slots cut in it.
Once the steel is back up to temperature, I let is soak for 15 minutes and remove the pouch and press it between two copper plates and blow compressed air on the whole works for a few minutes. It's cool to touch very quickly.
Open the pouch with scissors and reveal the blade.
I like this unusual oxidization pattern.
No to time waste, into the tempering oven for 2 cycles of 200°C for 2 hours each.

This is the product after tempering is complete. It's unfortunate I cannot keep the cool colours. They will be sanded off in the next step.


Jason said...

Did you add the thin bricks to the floor in order to decrease the volume and speed up ramp time? How is it working with the new height vs original?

D. Comeau said...

Yes I added about 1" of brick to the bottom of the chamber. I can't really say how much of an improvement it made to the temperature curve. I did some other improvements at the same time, sanding and fitting the door more precisely, new screw type door latch etc. I did notice that new coils really make a difference though. Coils seem to get weaker with usage.