Tuesday, 1 December 2009

Glueing Glass Pieces

The best solution is to avoid the use of glue completely. If you cannot, use as little as possible and make sure it burns out cleanly.

The glues to which kiln workers have normal access, do not survive to tack fusing temperatures. Therefore they can only be considered as a means to get the glass assembly to the kiln. The glue will not hold the pieces in place until the glass begins to stick, so the pieces must have a stable placement. If not, the pieces will slip, roll and move once the glue has burned out.

The second requirement of glues is that they burn out without leaving a residue.

Glues that have been used with little or no residue include:

-CMC (carbyl methyl cellulose) is a cellulose based binder used in a wide variety of industries, including food. For our purposes, it is also used in the ceramics industry and is often called glaze binder. It is a main constituent of "glas tac" from Bullseye. This can be made up into a viscous solution to catch and hold frits and other sprinkled elements in place.

- PVA (Polyvinyl Acetate) is water-based glue. It is sometimes known as school glue. It can be diluted to about 10parts water to 1 part PVA. This is sufficient to hold the glass pieces together with only a drop for each piece of glass. It does not work so well for small sprinkled elements.

- Super glue burns off with no concerns about cyanide. It should be used sparingly and also works best for pieces of glass.

- Hair gel can be used to catch and hold small elements in place.

- Hair lacquer is normally sprayed over the assembled piece and so can be used to hold pieces of glass as well as sprinkled elements.

In all uses of glue the principles to remember are:
- Use the minimum to hold pieces together while getting the work into the kiln.
- Put the glue at the edges of the glass or where its combustion gasses can escape easily.
- And in all cases, you need to test to see if a residue is left on the glass at full fuse when using a new glue.

[edited 14 Nov 2010]