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| Credit: Glass Art by Margot |
Small pieces, confetti and stringers which are glued often move out of place during firings. Glue, whether dry or wet, often boils at relatively low temperatures. This can be enough to move, or displace, and even flip light pieces.
The alternative to glue is to use a thin film of clear powder. First arrange the pieces and then place a fine film of powder at the edges of the pieces. At tack fuse and above, the powder will incorporate with the base glass and be invisible.
One caution is that a thick layer of powder which obscures the base glass will produce a sandpaper finish at tack temperatures, and at worst produce a multiplicity of tiny bubbles making things look grey at the finish.
In low temperature tack fuses, use a few grains of fine clear frit on either side of anything that might be subject to rolling or sliding to avoid the rough or grey appearance.
But...
If it is necessary to use glue to transport it to a remote kiln, use the minimum amount, diluted with 50% or more water, or solvent if solvent-based. Add only a small drop of the glue to the edge or end of the pieces. This avoids the glue leaving large black spots under the pieces because the burnout products cannot escape. It also prevents large amounts of glue being used.
Most of the glues have boiling points below 270°C/518°F, so a slow ramp to that temperature will create an evaporation rather than boiling and displacing the glued pieces.
