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Over cooked stone?

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paulc:
Is this what over cooked stone looks like?

Too hot? Or too long? Crappy stone? Thanks for your thoughts?

Paul

bjrogg:
It could be. I’m not sure. Is that what it looks it when you try to flake it.

If you overcook it it becomes very brittle. It just kinda crumbles when you hit it. Breaks instead of flakes
At least that’s what happened to the stuff I overcooked.
Bjrogg

JEB:
That looks like crappy cracked up Texas rock to me. I bring home a couple 5 gallon buckets of the stuff after the winter months out west and maybe I get a 1/2 a 5 gallon bucket of good stuff.

paulc:
JEB, it is Texas rock. I had purchased perhaps 8 or 10 stone in a box from an online vendor. Probably 3/4 looked like this after cooking. It just crumbles and fractures randomly when  hit....it is nice and waxy but crazed and I can do zip with it. Maybe if I had cooked it less BJ it would flake proper?

Paul

JackCrafty:
Yes, that's one type of heat treating fail.

The heat was probably too high. A lot of TX rock, especially the darker colors and translucent stuff, needs only slight heat. Some as low as 275 F. I usually test a few spalls at 300 F. That way, I don't lose too much stone in the test phase.

The stone doesn't look crappy. Did you try to knap some raw?

"Too long" is usually not a thing. Stone can stay hot for days without problems.

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