Has anyone played with Graphite mixes in plaster molds? I know that HOT, it works very well for a bright surface. But how does it hold up to the Long cycle in the oven?
Current plan is to try a graphite/kaolin wash and a graphite Alumina wash, on the inside of the molds prior to firing. I'm also trying some of the above on the positives, hoping that the plaster will bond to it, and hold as the negative is removed.
Greg
Graphite kiln wash
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Bert Weiss
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Re: Graphite kiln wash
Gregwatershed wrote:Has anyone played with Graphite mixes in plaster molds? I know that HOT, it works very well for a bright surface. But how does it hold up to the Long cycle in the oven?
Current plan is to try a graphite/kaolin wash and a graphite Alumina wash, on the inside of the molds prior to firing. I'm also trying some of the above on the positives, hoping that the plaster will bond to it, and hold as the negative is removed.
Greg
I think you'll find out that the carbon burns up in the long heatup in the kiln.
There might be some sort of quality difference in different forms of carbon.
I hope I'm wrong. Let us know what you find out.
Bert
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Results. Finally got the pieces out and divested yesterday. Did some cold work today.
Graphite kiln wash in the bottom of the mold, on embedded kiln shelf, UNDER frit. No obvious results other than failure.
Alumina Wash: This wash brushed on a dry-ish mold. Water and Alumina to a thin skim milk color. Noted some increased clarity and lowered clean up. More trials are needed. One note, on 50/50 molds, the wash tends to soften the mold, if the mold is drier than wet.
I will do more research on the Alumina, and probably some tests on 50/50 Alumina Kaolin (Salt kiln wash).
Greg
Graphite kiln wash in the bottom of the mold, on embedded kiln shelf, UNDER frit. No obvious results other than failure.
Alumina Wash: This wash brushed on a dry-ish mold. Water and Alumina to a thin skim milk color. Noted some increased clarity and lowered clean up. More trials are needed. One note, on 50/50 molds, the wash tends to soften the mold, if the mold is drier than wet.
I will do more research on the Alumina, and probably some tests on 50/50 Alumina Kaolin (Salt kiln wash).
Greg
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Lauri Levanto
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As I understand, kaolin is used in kilnwash
as binder. It makes a clay body to keep the
inert AlO in place.
50/50 seems to sintrate quite solid in higher temps.
20/80 gives a soft onetime mix. The kaolin particles
are so much apart they do not sintrate solid.
My best surface results are about 30/70 plaster and AlO.
Neither part is reactive to glass. I use it in very watery mix.
I pour the mix into mold, and after few seconds out.
Some softening of details is unavoidable, but the glass
gets a satin finish. The major problem is that this is a onetime mix due to the setting of plaster.
Much vaste of AlO.
-lauri
as binder. It makes a clay body to keep the
inert AlO in place.
50/50 seems to sintrate quite solid in higher temps.
20/80 gives a soft onetime mix. The kaolin particles
are so much apart they do not sintrate solid.
My best surface results are about 30/70 plaster and AlO.
Neither part is reactive to glass. I use it in very watery mix.
I pour the mix into mold, and after few seconds out.
Some softening of details is unavoidable, but the glass
gets a satin finish. The major problem is that this is a onetime mix due to the setting of plaster.
Much vaste of AlO.
-lauri