440c heat treat

[myszkawa]

When you heat treat 440c is it absolutely necessary to use foil or some other thing like turco. What happens if you just put it in the kiln? will it wreck the blade?

 

[Nathan the Machinist]

It won't wreck the blade, but you'll have quite a bit more clean up to do. The steel will be pitted and you will need to grind away at least .010 from all surfaces to remove the burnt carbon depleted steel (surface decarb).

 

[Bailey Knives]

Yep, I have made a few knives like that in the distant past. It is a LOT of work to get it to a nice condition. I later sent a knife to Paul Bos for heat treat. I had hand sanded it to 400 grit before hand, and wish I had gone higher. When it came back it was slightly discolored (kind of yellow) but it cleaned up in 2 passes with sandpaper and was ready to go. I had ground it to the edge I use for secondary bevel. I guess what I am saying is it would be worth your time and money to keep the pits and scale off the knife if at all possible.

 

[AcridSaint]

I think the cost for foil ends up being about a buck a blade, two if you double wrap. The question to ask is how much of your time does that two bucks buy? Not that much.

 

[Salem Straub]

Yes, foil all the way. The few stainless blades I've hand sanded after an unprotected heat/cool were a BEAR to get the scale off of. It'll even be resistant to being ground off. That SUCKED.

 

[elementfe]

I've not worked with stainless, and I'm curious about what happens when you pull it out of the oven- do you strip the foil off, or let it cool with the foil on?
It would be interesting to see a time/temp chart for the ideal cooling rate for air quenching 440c.
Andy G.