lapidopterix
starting to spend too much on rocks
Member since March 2008
Posts: 216
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Post by lapidopterix on Apr 27, 2008 15:31:30 GMT -5
I heated some of my carnelian (and a tigereye endcut) and got a good color change. I think I saw this recipe somewhere on the internet but I couldn't find it recently. Rocks were placed in a metal casserole pan and covered with silica sand. Temp steps were as follows: 1 hour @ 200 F 1 hour @ 300 F 1 hour @ 400 F 2 hours @ 500 F 2 hours @ 550 F Then cool down over night. Before After
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Post by akansan on Apr 28, 2008 22:31:06 GMT -5
How important was the silica sand?
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lapidopterix
starting to spend too much on rocks
Member since March 2008
Posts: 216
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Post by lapidopterix on Apr 29, 2008 1:22:31 GMT -5
I'm not sure how important the sand is. I think it's mainly to prevent thermal shock and hold the heat longer once you're at temp. It would probably help absorb shock if a rock blew up. You can do without though, I talked to someone a couple of weeks ago that heated some up in a pan on the stove.
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dshalldms
starting to spend too much on rocks
Member since January 2008
Posts: 113
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Post by dshalldms on Apr 29, 2008 2:39:36 GMT -5
In answer to the sand question...
The stones should be completely covered by the sand, this gives a more even heat to the stones and prevents colour zoning.
Derek
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cutter
starting to spend too much on rocks
Member since February 2008
Posts: 129
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Post by cutter on Apr 29, 2008 7:33:49 GMT -5
This is unfamiliar territory for me. What is th objective of this heating process?
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lapidopterix
starting to spend too much on rocks
Member since March 2008
Posts: 216
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Post by lapidopterix on Apr 29, 2008 17:01:10 GMT -5
It's used to change the color of carnelian and tigereye. A similar process is used on agate and petrified wood to make them usable for flintknapping.
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