Calculating amount of glass for a casting by weight of clay?

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Geo
Posts: 48
Joined: Mon Jul 07, 2003 8:54 am

Calculating amount of glass for a casting by weight of clay?

Post by Geo »

Hello,

Can someone please remind me how to calculate the amount of glass I will need for a casting, based on the weight of a clay model?

Thank you!
Yardic Glassworks
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Joined: Sat Mar 06, 2010 9:29 am

Re: Calculating amount of glass for a casting by weight of c

Post by Yardic Glassworks »

Clays can vary a bit, but when using the low fire clay that I use, it is weight of clay X 1.40 equals glass weight. There are others here who use clay much more than I do, so they may have some additional calculations that they use. Tim
Tim Yardic
Yardic Glassworks
nbobb
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Re: Calculating amount of glass for a casting by weight of c

Post by nbobb »

Or, you can form the clay into a shape, like say a cube, calculate its volume in cubic centimeters, than take that volume times 2.5 to get the grams of glass that you will need. (2.5 grams/cubic centimeters being the density/specific gravity of Bullseye glass).
Nancy Bobb
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Stephen Richard
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Re: Calculating amount of glass for a casting by weight of c

Post by Stephen Richard »

2.5 is the approximate specific graivity of all soda glass. Lead glass and others are different.
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Soozin
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Re: Calculating amount of glass for a casting by weight of c

Post by Soozin »

or use the water displacement method.. Once you take the clay out of the mould, pour water in... and then use the displacement method...
Geo
Posts: 48
Joined: Mon Jul 07, 2003 8:54 am

Re: Calculating amount of glass for a casting by weight of c

Post by Geo »

Found my notes from an old project. A pretty soft and moist clay. Weight of clay x 1.3 worked perfectly. Thanks everyone.
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