I have some bisque plates that I would like to use as glass molds. I know that I need to drill holes in the bottoms of the molds but I’m not sure how large these holes can be before they cause an issue with glass melting into the depressions created by the holes. I have a 1/8″ diamond bit; would this create holes that are too large?
A 3mm hole in a ceramic mould will be fine unless you slump at high temperatures. Be sure to put the hole(s) where the glass will last touch down onto the mould.