Will this work?

Bethany · Post by **Bethany** » Wed Dec 17, 2003 8:23 am

Hi warm glassers - relative newbie and first time poster here. This list and website has been a huge boon to my warm glass knowledge since previously I was a flameworker only.

I have some box bases (4.5" round opening) for which I want to fuse some 'tops'. Rather than just a flat round, I want to have an inner lip so the lid is more secure. In other words, I want a smaller circle indented under a larger one.

Initially I thought to use thick fiber paper (the stuff that is around 1/8" thick) but I had trouble getting a nice clean circle cut out. So I was thinking to go to the shop where I buy my greenware, get some clay, roll a sheet out 2 thicknesses of glass high and cut out the center circle like one might do in cookie dough, then fire to bisque and kiln wash.

Then I would put the my smaller circles (2 thicknesses) in the open hole and lay the larger circles over the top on a shelf. Kind of like laying a drop ring right on a shelf but filling the center of it, not 'dropping'.

My questions are
1) do I need to fuse the inner two and outer layers of circle separately into blanks and then put them together and tack fuse or full fuse? I want a good solid bond so I thought full fuse?

2) is there a better way to accomplish this than my plan?

Thanks!

rosanna gusler · Post by **rosanna gusler** » Wed Dec 17, 2003 8:39 am

generally, you do not want to slump over clay. i think you need an exacto knife with a new blade. take your time cutting the circle out of fiber paper. scissors work as well but it will ruin them for cutting finer materials. rosanna

Bethany · Post by **Bethany** » Wed Dec 17, 2003 9:21 am

Thanks Rosanna - I guess I can try fiber paper with a razor blade and a form.

Why the taboo on slumping over clay - esp flat clay that is very nearly dish like? Just curious.

rosanna gusler · Post by **rosanna gusler** » Wed Dec 17, 2003 10:10 am

the glass shrinks more than the clay on cool down. if your clay shape is one that can be trapped , the glass will break. the clay route for what you want is alot more time and labor intensive than the fiberpaper. rosanna

Barbara Muth · Post by **Barbara Muth** » Wed Dec 17, 2003 10:12 am

Bethany,

Glass and clay expand and contract differently. When you are done firing, the clay will have contracted more than the glass. That will set up some stress in the glass and you will have to break your clay form to get the glass out. No guarantees on whether or not the glass will break as well. You can address this problem by lining the inside of your ring with a strip of fiber paper, but I would probably cut the circle from the fiberpaper.

Barbara

addendum: I meant to say that the glass would have contracted more than the clay. I need to be lucid when I post!

Ron Coleman · Post by **Ron Coleman** » Wed Dec 17, 2003 10:14 am

You could have a problem if your glass slumps over the edges of the clay mold. Since glass shrinks more than the clay, it may crack on cooling. Just working on top of and in the center of a clay mold shouldn't be a problem.

Ron

Bethany · Post by **Bethany** » Wed Dec 17, 2003 11:54 am

Thanks for clarifying - that could be very helpful down the road, the contraction rate information.

Ron, I am thinking on the same wavelength with you. The glass should not go over the outer edges of the clay, only on top and in the cut out. I think for fun I will try it both ways, fiber paper and clay. Should prove to be an education

.

Thanks agian!

charlie · Post by **charlie** » Wed Dec 17, 2003 12:06 pm

you also have to remember that clay shrinks as it dries, anywhere from 5-15%.

also, clay has to be bisqued before use, and heating non-dry clay will result in an explosion. you might try drying your slab between 2 sheets of drywall. that will keep it flat and dry it faster.

Bethany · Post by **Bethany** » Wed Dec 17, 2003 1:14 pm

Thanks Charlie, I most certainly would plan to fire properly to bisque. I appreciate the input

Joanne Owsley · Post by **Joanne Owsley** » Wed Dec 17, 2003 10:19 pm

[quote="Bethany"]Thanks for clarifying - that could be very helpful down the road, the contraction rate information.

Ron, I am thinking on the same wavelength with you. The glass should not go over the outer edges of the clay, only on top and in the cut out. I think for fun I will try it both ways, fiber paper and clay. Should prove to be an education

.

Thanks agian![/quote]

I'm with you. I think if the objective is to have the glass slump down into the hole in the center of the clay, leaving only a small lip on top, there really isn't any reason that this wouldn't work. We slump bowls into clay all the time with no problem. Perhaps I'm misunderstanding the overall objective. (Overall objective?!?! Can you tell I facilitated a 3 hour business meeting today? LOL)
Anyway, I say give it a try. Don't forget your kilnwash, and plan on maybe having to coldwork the outer edge, but it should work.