09/02/2026
We spent the first week of the semester sandcasting. Why?
It was hot!!! We don't have to turn on some of the heat generating equipment to do sand casting, so it keeps the temperature down in the shop.
Sand casting is pretty simple. You start with a container full of slightly damp, sifted sand - any sand could work, but magnesium iron silicate (olivine or synthetic olivene) is the preferred. You press a model in and pack the sand tightly around it, then remove the object leaving an impression. Model choice is important because you can't have any undercuts and deep, thin detail probably won't fill properly and the sand impression may be delicate in those areas and crumble before you get the glass in. Simple is generally better.
You then have to apply a mold release to keep the sand from sticking to the glass. Many things can be used, but my favorite is soot from an acetylene flame.
Then, simply grab your large casting ladle and get a scoop of glass out of your handy-dandy glass furnace and pour it in.
You have to wait for the glass to cool down and firm up before you dig it out and take it to the kiln to properly anneal. You can't wait too long though because if it cools too much it will crack. When you have thick and thin areas in the same casting, you frequently have to use a torch to keep the thin areas hot while the thick areas cool down.
All in all though, its a pretty simple way to cast glass and has a unique aesthetic.
