Case Hardening with a Charcoal Furnace

[TomG]

I promised a video on this a while back and finally got around to making it. The forced air charcoal furnace took a few attempts to get right, but this one worked like a charm. It was able to get a fairly large package of parts up to around 1500º and keep them there for an hour. The only problem I had was the cheap craft SS foil burned through. That allowed some oxidation of the parts, but they still hardened up just fine.

Tom

[Highpower]

Tom, how long ago did you buy your can of Kasenit? I thought it was no longer available and replaced by Cherry Red?

[awemawson]

They changed the Kasenite formula - certainly for what is sold here in the UK, as it originally contained various cyanide compounds as enhancers.

The new stuff is not a sticky as the old. You used to be able to heat a part to red heat, dip it in the tin, bring it out covered in a nice coating and re-heat with a torch. The new stuff stays powdery and blows away with the torch :(

Doesn't matter if boxed like Tom did it.

I'm intrigued whether it's got the name Case Hardening as it makes a hard 'case' around the part, or from the box (case) that it was originally done in, in a Furness.

[Highpower]

I still have a can of the "old" Kasenit but the places I always used to find it no longer carry it, and offer the Cherry Red now instead. I bought mine from Brownells many years ago.

I did notice on the McMaster site that they offer two different "types" of case hardening compound. They don't give out the brand name in 99% of their items so you never know what you are going to get. But they show a "dip" formula and a "pack" formula. I'm assuming the "pack" version is just a courser grind? I'm wondering which one Tom used in his video because it looked pretty fine, like my can of the "dip" version?

[TomG]

Mine is the dip kind. I think the pack kind just lacks the binders to make it sticky.

Tom

[pepi]

Thanks Tom,

Saving this for the future, good production, covered and explained the total process clearly.

Well done
Greg

[TomG]

Thanks Greg. It was a fun project.

Tom

[awemawson]

Tom, have you done any experiments to see how deep a case you have achieved?

(It shows up in a cross section when polished and etched like testing a weld for penetration)

[Mayhem]

What thickness was the SS foil Tom?

[TomG]

It was .002" Darren, but I have no idea what alloy it is.

Tom