I used a clay guide to make the molds. That way all the molds had similar shapes and the final glass pieces could easily be combined. I bisked the clay to cone 012 or 1600F for that was the temperature that I was going to take the glass up to.

I made four molds. Two different sizes.

Two of the pieces had MnO2 mixed into the glass and the other two had copper carbonate. I put Nickel Chromium (NiCr) wire around the mold to make sure that if the mold came apart the glass wouldn't flow into the kiln. I put a fiber blanket where the mold was close to the elements.

Next step was to break of the lip of the clay so that the top of the melted glass was at the same hight as the beginnig of the clay mold. You can do that with a saw if you have such a low fired clay I was useing or as I did in this case I just took some tweesers and broke the lip off. The best tool is a tile saw with a tile saw blade. It will get the mold wet but it will dry fast in the kiln during your low heat setting on your way up again. The clay walls are so thin that it will not harm the glass being moist. Best though for your kiln not to have that extra moisture so if you have time air dry your molds if you get them wet.