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Slimping into Terra Cotta Mold.....
Posted: Wed Jul 09, 2003 12:09 am
by Stuart Clayman
I found some old molds at a studio and I tried them.. the slumped pieces came out with a matte finish on them... not devit.. just matte.. can anyone tell me why?
Posted: Wed Jul 09, 2003 6:16 pm
by Brad Walker
Top or bottom?
Posted: Wed Jul 09, 2003 8:44 pm
by Stuart Clayman
Top. The bottom was as I expected it.
Posted: Wed Jul 09, 2003 9:31 pm
by Ron Coleman
It may be evil vapors from the molds if they have been sitting around for a long time. You could try firing them high (1500) without glass a time or two and see if that helps.
Ron
Posted: Thu Jul 10, 2003 1:01 am
by Stuart Clayman
Ron,
You may be on to something... Evil Vapors? ... PLease explain.. the molds have been sitting around for a long time. I got them from a studio that had not used them in years.
Stuart
Posted: Thu Jul 10, 2003 8:02 am
by Ron Coleman
Evil Vapors or outgassing from the molds may be caused by surface contamination or something absorbed into the clay over time. It's hard to tell what it may be.
I always like to throw experiments in the kiln while other things are firing just to take advantage of the extra shelf space. I have found that firing any kind of chemicals (like copper carbonate) exposed to the kiln atmosphere can fog other glass in close proximity.
Ron