- May 29, 2011 at 2:40 am #9590carolynfiskParticipant
Can somebody send me a link to find out how to make clay molds for slumping? I need to know how long to dry before putting in kiln, kiln temperature and time? Thanks. CarolynJune 6, 2011 at 7:31 pm #12083SolonmParticipant
I have made several molds to use with slumped glass. I use a mid range temp., cone 5, white stoneware and fire it to a bisque temperature of around 1800 degrees or about cone 05. I think that clays with colorants such as red earthenware might have too many impurities in it and cause gases to escape and contaminate the glass though this is just a guess. I did fire one mold in my glass kiln to 1700 which was the max temp. for that kiln. It seemed to work just fine. Ramp up slowly to allow any moisture to leave the piece. I roll the slab to about 3/8 inch thick. Be sure to score any piece that is being attached to another and use slip (dry clay and water) to moisten the joining areas. Allow to fully dry before firing to prevent the piece from blowing up. Use several coats of kiln wash on any surface that will touch your glass. As a former potter, I was able to throw some cylinders and bowl forms too. I haven’t time tested them yet so I do not know how they will hold up over time as compared to commercially made molds. I particularly like making one of a kind waves and other shapes.
I’m sure there are some artists who are casting molds from clay slip which would make a mold similar to those available from the commercial vendors. That is another coversation. I’d like to hear about that too. Good luck.June 7, 2011 at 12:17 am #12084carolynfiskParticipant
Thank you for you excellent information. I was able to make the piece that I needed, and while I was sure it would blow up, it did not. I fired the mold in mh oven very slowly to be certain it was dry before I put it in the kiln, and then ramped up slowly in the kiln and did not have a problem. I will be able to use the mold several times. I am always very cautious when trying a new procedure and had never made anything out of clay – so now I know how to do it.
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