devit on bas relief kiln cast sculpture

Judi Charlson · Post by **Judi Charlson** » Mon Apr 07, 2003 7:53 pm

I have just read much about devit in the archives, but still have some questions about how to deal with devit on a piece I am going to donate to the animal rescue league art action.
It is 11 "H,15"W, and 1 1/2 D. A pate de verre high relief type piece of a boy throwing a ball into ocean with two dalmation dogs jumping up in the surf. The devit(molted irregular white scum) appears randomly all over the marine blue ocean and sky bue sky, but the boy and dogs are fine. thought I would mask the figures and dogs, sand blast, then seal with Watco Danish oil.
How can I mask off the figures and dogs?I heard elmer's glue could be used, but then how do I remove it cleanly without disturbing the background which will be sandblasted. I hate the blasted devit. I think I held it too long at melting point.
Any suggestions? Is there a better sealer than the Watco oil?
Thanks,
Judi

charlie · Post by **charlie** » Mon Apr 07, 2003 7:57 pm

elmers glue is water soluable.

Steph Mader · Post by **Steph Mader** » Tue Apr 08, 2003 1:55 am

Judi,

Is the devit on the front or the back of the piece?

Steph

ellen abbott · Post by **ellen abbott** » Tue Apr 08, 2003 10:40 am

If it's on the surface that was embedded in the mold (the 'front'), it's not devit. We get it a lot. It's a chemical reaction between the glass and the silica. They are trying to become one. Some colors are more suceptible than others. Some colors that get it clean up very easy, some are impossible unless you grind it off. If you figure out how to avoid it, let me know. But we have tried all manner of things. However, when you mix colors, there's no way to completely avoid it. If you fire long enough for one color, it's too long for another. The sky blue is susceptible. Haven't used the marine blue enough to remember, but looks like it is too.

ellen

Judi Charlson · Post by **Judi Charlson** » Tue Apr 08, 2003 2:56 pm

Ellen,
Thanks for your reply. The unwanted white scum is indeed on the surface that was embedded in the mold.(embedded taskes on such new conatations now doesn't it) I would have never thought that it was caused by a reaction with the silica. Now I wonder if a barrier can be appled between the mold and the frit that is invested into it. I hear so much about Spray A and other sprays for the surface of slumped glass. Do you or does anyone else know any remedy for this?
I have applied Elmer's glue to the "clean" areas and I am going to try to sandblast the sky and ocean at the local glass center, then apply Watco oil.I am thinking about tinting the oil. It 's a nice piece and took a week in the kiln, so I want to try to fix it. I usually do nude figures and I think the Animal Rescue League would rather have this piece in their auction.
Thanks again
Judi
Judi

ellen abbott · Post by **ellen abbott** » Tue Apr 08, 2003 6:21 pm

Sometimes, I will put down a thin layer of clear against the mold surface and then apply my colors since the clear doesn't seem to be affected by those little buggers. But that's not always possible depending on how I plan to manipulate the glass frits.

ellen

Judi Charlson · Post by **Judi Charlson** » Tue Apr 08, 2003 8:13 pm

Ellen,
I will try a layer of crystal clear frit for the first layer. Great idea.
I sometimes place a layer of clear over colors that I don't want to blensd with top layers and it seems to work
.Judi

Paul Tarlow · Post by **Paul Tarlow** » Thu Apr 10, 2003 12:29 am

ellen abbott wrote:If you figure out how to avoid it, let me know. But we have tried all manner of things.

Try adding 3% alumina hydrate to your mix and/or brushing colloidal silica onto the mold. Both tips attributed to Ruth Brockman.

- Paul

Tim Lewis · Post by **Tim Lewis** » Mon Apr 21, 2003 4:17 pm

Also add 5-10% Kaolin to the mix and it will help too.

WarmGlass.com