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glass shrinkage

Posted: Wed Jun 25, 2003 9:25 pm
by Luiza
Hi
I have to fuse one layer of glass - 3mm. I know that there will be some shrinkage. I want that the final piece to be 8.3X7.5 in. Is there any formula that I can use to calculate the size of the original glass? Is it linear, or the shrinkade depends upon the area?
Thanks
Luiza

Re: glass shrinkage

Posted: Wed Jun 25, 2003 9:27 pm
by Bert Weiss
Luiza wrote:Hi
I have to fuse one layer of glass - 3mm. I know that there will be some shrinkage. I want that the final piece to be 8.3X7.5 in. Is there any formula that I can use to calculate the size of the original glass? Is it linear, or the shrinkade depends upon the area?
Thanks
Luiza
Test

Re: glass shrinkage

Posted: Wed Jun 25, 2003 9:42 pm
by Brock
Luiza wrote:Hi
I have to fuse one layer of glass - 3mm. I know that there will be some shrinkage. I want that the final piece to be 8.3X7.5 in. Is there any formula that I can use to calculate the size of the original glass? Is it linear, or the shrinkade depends upon the area?
Thanks
Luiza
What do you mean, "fuse one layer of glass "? You should be able to fire polish a pices of glass that size without it trying to achieve equilibrium thickness. Brock

Posted: Wed Jun 25, 2003 9:53 pm
by Luiza
Well, I won´t really fuse it, but I want to texturize it with some forms done from fiber paper, and I´ve done lots of tests and I found that it has to stay 10 min soak at 1470 F, to be perfect.
Thanks
Luiza

Posted: Wed Jun 25, 2003 9:57 pm
by Brock
Okay. See Bert's post. Brock

Posted: Wed Jun 25, 2003 10:01 pm
by Luiza
That´s not fair :lol:
At least it is linear???? If I test one I can apply for any areas????
Please, say YES
Luiza

Posted: Wed Jun 25, 2003 10:08 pm
by Brock
I don't know. The longer you're hot the more it'll pull in. Why can't you make it out of 6 mil glass? The tiles look better. Brock

Posted: Wed Jun 25, 2003 10:24 pm
by Luiza
It´s not a tile. I´m doing 18 pieces of glass to decorate a bathroom door, and the idea is to have diferent textures. So I decided to texturize one layer, and I´ll put it together with another blasted or "sponge painted", so that it has a good appearance from both sides, and will not be transparent.(Some privacy...). They will be at a door of a bathroom of a person that bought my first sink. I´m so proud!!!!!! And I´m also so gratefull to Bert and Carol. Good friends, both of you...
That´s why I can´t use 2 layers. Any idea to make things easier?
Luiza

Posted: Wed Jun 25, 2003 10:29 pm
by Brock
Luiza wrote:It´s not a tile. I´m doing 18 pieces of glass to decorate a bathroom door, and the idea is to have diferent textures. So I decided to texturize one layer, and I´ll put it together with another blasted or "sponge painted", so that it has a good appearance from both sides, and will not be transparent.(Some privacy...). They will be at a door of a bathroom of a person that bought my first sink. I´m so poud!!!!!! And I´m also so gratefull to Bert and Carol. Good friends, both of you...
That´s why I can´t use 2 layers. Any idea to make things easier?
Luiza
Are these going into a matrix, lead, or wooden mullions? How are the two tiles being assembled? Do you have access to a tile saw or a wet belt sander? Brock

Posted: Wed Jun 25, 2003 10:37 pm
by Luiza
It´s a wooden door, six lines with three columns of glass.
I have a sander, but not a wet one, and no, I don´t have a tile saw. It was a long discussion, the tile saws here are 11000rpm...
I was thinking that I could glue the two tiles with UV glue...Good idea?
Luiza

Posted: Wed Jun 25, 2003 10:45 pm
by Brock
I'd go with GE silicone, the UV glues require a very smooth fit between the layers. Silicone is much more forgiving. You could also use the silicone as the bedding compound in the mullions. Now, as to the size.

Test.

Brock

Posted: Wed Jun 25, 2003 10:47 pm
by Luiza
Thanks a lot. Silicone will be much better!!!!!!
Ok, ok, I´ll do the tests :cry:
Luiza

can´t sleep - now I´m curious

Posted: Wed Jun 25, 2003 11:04 pm
by Luiza
Brock
What would you suggest if I had a wet belt sander and a tile saw????
Luiza

Re: can´t sleep - now I´m curious

Posted: Thu Jun 26, 2003 2:01 am
by Brock
Luiza wrote:Brock
What would you suggest if I had a wet belt sander and a tile saw????
Luiza
I wouldn't be worried about shrinkage, I'd make the tiles oversize and cut them down to the exact size you require. Brock

Re: can´t sleep - now I´m curious

Posted: Thu Jun 26, 2003 6:22 am
by Luiza
Brock wrote: I wouldn't be worried about shrinkage, I'd make the tiles oversize and cut them down to the exact size you require. Brock
I hate an obvious answer to a silly question. :oops: I deserved it :lol:
Thanks for your help, Brock, I´ll begining my test NOW.
Luiza

Posted: Thu Jun 26, 2003 9:22 am
by Bert Weiss
Luiza wrote:Well, I won´t really fuse it, but I want to texturize it with some forms done from fiber paper, and I´ve done lots of tests and I found that it has to stay 10 min soak at 1470 F, to be perfect.
Thanks
Luiza
Luiza

I have done plenty of work around 1470 for 10 minutes. I now like 1365 for 1 hour. As long as devit is not an issue, this schedule yields a nicer surface on the bottom.

I guess that the size change will be different for various thicknesses. I find that the size doesn't change much for me. Sometimes not at all.

Posted: Thu Jun 26, 2003 7:10 pm
by Luiza
Bert Weiss wrote:
Luiza

I have done plenty of work around 1470 for 10 minutes. I now like 1365 for 1 hour. As long as devit is not an issue, this schedule yields a nicer surface on the bottom.

I guess that the size change will be different for various thicknesses. I find that the size doesn't change much for me. Sometimes not at all.
I´ve done some tests today, and I found that my 3mm layer - 21X19 cm -
was reduced to 20.3X18.2 cm. The worst are the edges - the layer is not a perfect rectangle anymore, it has 4 ugly edges.
I´ll try 1365 for 1 hour tomorow.
Thanks
Luiza

Posted: Fri Jun 27, 2003 12:41 am
by Bert Weiss
Luiza wrote:
Bert Weiss wrote:
Luiza

I have done plenty of work around 1470 for 10 minutes. I now like 1365 for 1 hour. As long as devit is not an issue, this schedule yields a nicer surface on the bottom.

I guess that the size change will be different for various thicknesses. I find that the size doesn't change much for me. Sometimes not at all.
I´ve done some tests today, and I found that my 3mm layer - 21X19 cm -
was reduced to 20.3X18.2 cm. The worst are the edges - the layer is not a perfect rectangle anymore, it has 4 ugly edges.
I´ll try 1365 for 1 hour tomorow.
Thanks
Luiza
Luiza

It sounds to me like you have a few alternatives. You can make the piece 1-2" larger on all sides and cut it down with a glass cutter. You can try 6 mm glass or 10mm. Or maybe the lower temp will have a different effect.

It is interesting to me that you have the shrinkage problem. I guess that the factor of glass wanting to be 6mm holds close to true all around.

Posted: Fri Jun 27, 2003 8:53 pm
by Luiza
Bert Weiss wrote: Luiza

It sounds to me like you have a few alternatives. You can make the piece 1-2" larger on all sides and cut it down with a glass cutter. You can try 6 mm glass or 10mm. Or maybe the lower temp will have a different effect.

It is interesting to me that you have the shrinkage problem. I guess that the factor of glass wanting to be 6mm holds close to true all around.
Hi Bert
I was thinking of making a test - let a 3mm layer stay for some hours at 1470 F - maybe it becomes a 6 mm layer :lol:
I can´t use any glass thicker than 6 mm- that is the space I have -, and as I need 2 separeted layers, the thicker I can fire is 3 mm.
I tested the 1 hour 1365 F today. The kiln was still hot, so I could´n measure it. Now I´ll have to wait till monday...
Unfortunately I don´t have a tile saw, so I´ll have to manage another solution.
I imagine that you don´t have a faintest idea of how dificult is to work with glass or any other art or craft here. If some of you have interest I ´ll be happy to make a "brief" of this wonderfull and absolutely non conventional country in Spab´s place...There are very good things too - it´s not bad at all :D
Thanks again
Luiza

Posted: Fri Jun 27, 2003 9:24 pm
by Brock
I'd love to hear your "brief" Luiza. Brock