For these coasters, I’ve used a tack fuse, rather than a full fuse. This means the kiln is heated to a lower temperature so that the glass doesn’t melt completely. It’s a good way to create a texture on the glass. The temperature has to be high enough to stick the glass together but low enough that it doesn’t melt completely and flow into a smooth layer.
For these coasters I used different types of frit, which is tiny coloured pieces of glass. On the left, I used coarse frit and simply spread it upwards from the bottom of a clear coaster, becoming less dense nearer the top. On the right, I used medium frit and sprinkled it all over the base, before making a swirl in the red and sprinkling some amber frit into it.
The frit on both coasters has lost its sharp edges and become smoother, but the surface still feels textured, and they reflect the light nicely. The coasters still have quite square edges whereas, when they are fired to a full fuse, they become rounded and smooth.
It’s interesting how glass can be manipulated using heat to get the effect you desire. I’ll have to practice with this some more. There’s so much to learn, and it’s great fun!