3. Melt it til it pours
The above us another method of shaping glass into a mould that goes beyond making just bowls. The glass is fired until it runs down through a hole at the bottom of the flower pot and into your mould below. You can use another upturned flower pot as here, inside which you can place a smaller bowl or flowerpot that has at least 4 layers of batt wash ( which prevent the glass from sticking) covering the surface. If you use an inner flower pot you will just need to block the hole up first with a disc if kiln paper cut to fit the entire base of the pot first. Kiln fibre is another name for kiln paper as far as I can fathom and comes in different thicknesses and is meant to prevent things sticking where they shouldn’t.
I say meant to, as I’ve found 1mm fibre is okay for a single firing so long as you don’t add too much glass, leave firing at high temperatures too long or use slump glass in the mix. Slump glass is designed to get running it seems, but I’d steer clear of using it if you just want to fuse to make a flat piece of glass like a tile or coaster. It can run a lot any has done so in my kiln and can solidify as a veneer of glass which, while lovely as a finish is harder to remove from kiln shelf you want to reuse. It’s also not that cheap so is better reserved for shaped fusing. 3mm kiln fibre I found to be better option for most firings reserving 6mm sheets for long firings at high temperatures.
You can buy moulds specifically for glass fusing but the all need a coating of some kind to prevent glass sticking to it. Several thin layers of batt wash I found to be the best for shaped moulds. Before you buy a glass fusing mould, I recommend using unglazed garden pots that are made from clay simply because they are cheaper to replace if things go wrong is any vessel make from steel.
This 6 inch cake tin mould has no bottom and is made of stainless teel. It was shiny and brand new before the firing. The steel is a bit thin but it means you can peel off the steel from the glass it a little gets stuck to it. They idea was to make a series of glass panels this way, to maybe then turn into a lampshade or window. All did for this bit of glass fusing was line the bottom and sides of the mould with glass fibre. Job done.
I have a couple of steel bowls on order to experiment further. Why steel not aluminium…because aluminium melts at much lower temperatures but it means you can use it when you want it included in the glass project that you’re making as you as you fuse it. Always look up the melting point if anything you’re thinking of putting into the kiln before firing, or indeed when considering your design. It’s not just different metals that have different melting point temperatures, all things do including different types of glass which is why Tetra and Bullseye glass are used in glass fusing more than any other sort and you can order all you want if it from glass fusing suppliers. COE90 is the grade to look for when it comes to buying glass.