Expert: Leisha Hiester - 12/29/2008

Question
Dear Leisha
About 20 years ago I helped work on a re-financing deal for my employer with one of the big NY investment banks.
As a souvenir, I was given a glass paperweight, about 9 inches high in the shape of a dodecahedron.
I thought about using this as a slump mold to do something different this week.

How do I keep the clay slab from sticking to the glass and is there an optimal thickness for slump molding such a small piece such as 1/4 or 3/8 inch?

thanks

steve

Answer
Steven,
Congratulations on thinking outside the box! I've used lots of household & sentimental objects in my studio. Some I make a press mold of. I've gotten into doing this so much that I pick up fun stuff at Goodwill or garage sales for textures, slumping, etc.

My absolute best friend in my studio is WD-40! I spray the item first before taking an imprint or molding with clay. The clay doesn't stick, it helps make a clearer imprint and it burns off in the firing! Take some practice runs & see, warning, once you see results you could wind up with baskets & baskets of imprint items like I now have.

The only caution is that you don't mix WD-40 with a bisque item. If you get an oil thumbprint on a piece glaze won't stick to that spot. I learned this the hard way with a perfect thumbprint on a piece once. If you do happen to get it on a bisqued piece, simply refire the piece again & the oil will burn off.

To your question of thickness; I'm not sure if there is an optimal average for a slump mold. I make a variety of thicknesses depending upon the piece. I have purchased some glass slumping molds I use in my studio with clay from 'Slumpy's.' I've noticed the larger the piece, the thicker the mold. You might check them out & learn from their site more. www.slumpys.com

Let me know how your mold turns out. Leisha