HT san mai - coating?

[Stromberg Knives]

Hey guys!

I'm working on my first san mai blade. It has stainless 420 cladding and a 1095 core. I've forge welded, normalized, thermal cycled, annealed and profiled it. So far so good.

My question concerns the heat treat. Since it has a 1095 core I'm treating it as 1095. And when I heat treat high carbon steel I use ATP 641 for coating.

Should I still use the same coating even with the 420 cladding, to protect the 1095 core during HT?

 

[kuraki]

It won't hurt anything.

 

[Ken H>]

That would be my choice to use a coating to prevent crud build up. You're right, when HT'ing San Mai you only consider the core, not the cladding. Remember, the cladding is going to slow down the core quench (unless it's profiled with core exposed). I've used salt water for quench with San Mai since the core is protected by the cladding.

 

[Stromberg Knives]

That would be my choice to use a coating to prevent crud build up. You're right, when HT'ing San Mai you only consider the core, not the cladding. Remember, the cladding is going to slow down the core quench (unless it's profiled with core exposed). I've used salt water for quench with San Mai since the core is protected by the cladding.

Thanks for the advice!

Especially since it's near impossible to check the hardness of the core.

 

[Stacy E. Apelt - Bladesmith]

HT san-mai for the core. Ignore the cladding. The coating will be fine.

 

[DevinT]

I would try it without the coating, stainless is sluggish heating up and maybe cooling down. Even though it’s a thin coating, might slow the quench a bit. Not sure however.

Hoss

 

[HSC ///]

I’d suggest bevel grinding post ht. In that case there’s no need for any scale coating.

 

[Stromberg Knives]

I’d suggest bevel grinding post ht. In that case there’s no need for any scale coating.

Yep, I forgot to mention that. I always grind post HT, so that's my plan.

 

[HSC ///]

Yep, I forgot to mention that. I always grind post HT, so that's my plan.

So I can’t see any need for any scale coating....there’s no carbon steel exposed except for the top spine area and bottom edge,
Presumably these two areas will be ground anyway.

 

[Stromberg Knives]

So I can’t see any need for any scale coating....there’s no carbon steel exposed except for the top spine area and bottom edge,
Presumably these two areas will be ground anyway.

Yeah, you're right. It's pretty obvious when you put it like that.

 

[jdm61]

I was told by Burt Foster IIRC that he clayed up the spine as that were you could have issues like delam. I am guessing that he was quenching a blade that had been beveled.