I created a flask leaving a distance of 1cm from sculpture/flask sides and above 2 cm I connected the sides with glue gun, which allowed me to brake box open when sand was set.
I then mixed sand with a silica and filled the box, making sure to pack all intricate cuts of sculpt.
When the box was full of silica sand I drilled holes in the flask. The holes were than blasted with co2 gas which made the sand turn solid.
Once the sand cast was solid we burned the polystyrene away to create space for molten.
Molten is above 1250 centigrade.
Foundry in Chalford Uk that could be used for future work: Pangolin Foundry.