Saturday, 10 November 2012

Slumping Tack Fused Stringers

With a piece made up of tack fused stringers it is important to anneal carefully. There are a multiplicity of small contact points where the glass is little more than laminated. This means that each piece of glass will try to contract into itself rather than acting as a single unit. An annealing soak and cool should be chosen to be several times longer than its nominal thickness.

Slumping of this piece will also need to be done carefully. First, to ensure all the contact points can relax as soon as the thinner parts of the stringers. Second, the weight of the piece is not as great as one of the same size and so will not fall into the mould in the same way – it will take longer. Third, the movement of the glass will be within the fragile stringers so it is important to take the heat up slowly so they can bend rather than fracture . So, fourthly, it is important to establish a schedule that will have a slow rate of advance to the lowest possible temperature with a long soak for a slump of the required depth.