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Glass Sand Casting

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Sand Cast Glass Objects (2019)

Introduction

I was lucky enough be be invited to assist with some Glass Casting Classes at The Benzaitine Center for the Creative Arts. I had a great time seeing the expressions on all the children's (and some adult) faces as they participated in the process.

The Process

Sand mixed with Bentonite is sifted to declump and remove any large contaminants from previous use into a large box. A positive template, such as a shell or previously made sand casting, is then pressed into the sand mixture to create a negative cavity. An acetylene touch, without any oxygen, is used to deposit a layer of soot all over the cavity as a mold release. Molten glass is then ladled from the furnace and poured into the mold. After the glass has solidified, but still hot (~1200 degrees Fahrenheit), the glass object is put into an annealer. The annealer very slowly cools the glass down (~18 hours). The glass parts are then removed and any sand still sticking to it is wire brushed off.

The amount of detail that can be captured is quite remarkable considering the sand grain size and the viscosity of the glass.

An Attempt at Casting for a Panel

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Glass Casting made using CNC Template Glass Casting CNC'ed Template

I made a template using my CNC router hoping to make a centerpiece for a stained glass panel with a glass blowing theme. When we began to make the casting I was encouraged to add some colored frit in the foreground and after pouring, a different colored frit for the background. I did not do the best job of adding the frit. In the heat of the moment (pun intended) we forgot to pour the glass thin so the casting is probably too heavy to use in a stained glass project, never the less it shows great potential.