Sea Foam in a rock pool

Boiling glass is an extensive process which starts with scattering piles of crushed glass onto a kiln shelf. In this case, larger sections of aqua and vanilla glass were then layered on top, then a final full piece of streaky white glass was placed on as the final layer. The firing schedule initially increased the temperature rapidly which made the edges of the topmost piece flop down and seal the glass pile, thus trapping the air caught within the crushed glass. During the firing process, the air gathers together into a bubble which then pushes its way through the layers of coloured glass to the surface. The bubble will eventually pop then sink back down and fuse into the slab, creating the round areas of colour brought up from the bottom.

The brown colour which encircles some of aqua shapes and flows through some areas was caused by a reaction between the chemicals in the vanilla and the aqua glass components – one of the uncontrollable organic processes which gives extra unexpected results. I enjoy the way you can only control the outcome to a certain degree.  

A document detailing how the slab was blown by Phil Stokes into the vase is as follows:

FLG Glass Slab Rollup Process