Alright, so I bought one of these after my horrible clay-mixing and furnace cement experiences...
I applied it in a very thin layer to the blade, and let it dry for like... hour and a half. (from my understanding, this can be used right away, and does not actually need to dry for the purpose of differential hardening. Besides, instructions on the tube read "dry for at least an hour".)
But to my great surprise the thin layer expanded like a baloon as soon as I moved the knife into the forge... I mean - it was instantly. They blew up to large hollow bubbles on the blade.
I saw no o