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mold making

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mold making

Postby dr sawfish » Fri Sep 24, 2010 3:43 am

can you mix organic binder and fibre then compress into a negative mold to make a posotive shape for glass to slump over?
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Re: mold making

Postby marykaynitchie » Tue Sep 28, 2010 9:08 am

Hi Dr Sawfish,

It is possible to compress refractory fiber into a mold, rigidize it, and slump glass over it. Depending on the form you are slumping over, you may or may not get the result you want--because the glass might develop gathers and folds when slumped over certain forms.

Others may have ideas to share about materials and past experience.

Mary Kay
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Re: mold making

Postby bertglass » Tue Sep 28, 2010 1:08 pm

Mold mix 6, made by Zircar, is made with refractory fibers mixed with an inorganic binder. As Mary Kay said, draping over can sometimes result in wrinkled glass. However, not always. If the mold you drape over, has a lower coefficient of expansion than the glass, and the shape makes it difficult for the glass to ride up, the glass will crack. I am not aware of the COE of mold mix 6. Molds, like glass, must either be the right COE or be shaped such that the glass can move out of the way. Unlike glass, shape can be a mitigating factor, with molds. Plaster refractories I have used, contract more than the glass, making them a good drape over mold. You have to know your materials though. Olivine sand shrinks less than silica sand, for instance.
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Re: mold making

Postby Twin Vision Glass » Tue Sep 28, 2010 3:10 pm

http://www.zrci.com/lproducts.htm (just click on blue sections at the site and it will give you some written information on Mold Mix 6 and "user Guide" as well.) (when reading the user guide for Mold Mix 6 , please note that Zircar has not updated the firing schedule section for some years now , so please use the Bullseyer glass firing schedule for thick work.)
Here is a link to some products by Zircar Refractory comp. Yes they are very helpful. I have used their product for years, and have worked closely with Thomas Hamling to try to develop Mold Mix 6 for glass artists. It has it's good points and some very important points that if not followed correctly, you will waste this incredible product just by leaving it out in the open. If anyone is interested I believe I have a pdf on it, and how to use it for flameworking and for kiln casting.
This link has a few other moldable products as well. Take a look and see if anything is helpful.
http://www.twinvision.fusedglassartists.com/ Also from here is a PDF under Beadmaking and Moldmaking!
The amber girl with the basket on her head was cast in Mold Mix 6 at a Pilchuck Residency. I will nearly always back with sand when casting full size molds like this. We use Bullseye Shelf primer as a release inside the mold when casting to get this clean surface of the glass.
If you have any questions, do not hesitate to ask.
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