it is possible to buy stainless steel squares and circles in the USA....these are used to make flat pieces of glass by placing the square onto a shelf, or kiln paper, and putting lots of glass inside and allowing it to melt...kinda like a pot melt, expect without the pot! Also, they sell strips, which lock together different sizes of square or rectangle. If anyone knows of a supplier in the UK please could they post the info here? I have hunted everywhere without success, and they are too heavy to import.
could you post a link of what you are looking for?
You can get the same effect by using dams for right angles pieces or by cutting circles in larger pieces of vermiculite board. There are also stainless steel circles sold in cookery shops. In fact any stainless steel piece will do as long as it's properly covered in either batwash or lined with kiln paper. Think lateraly and utilise anything that will give you the effect you want regardless of it's original use.