Wednesday, 11 March 2015

Flow Melts without Metal

“Flows” seem to be popular just now.  These are variations either on aperture drops using multiple holes or on screen melts depending on the number of apertures.  This is not a complete tutorial, just some notes on how to prepare a more sound and so more lasting project.  It is not complete, as these flows are essentially incomplete screen melts or aperture drops.  The techniques and methods that apply to them apply to melts also.

It is inevitable that steel of a thickness that can support the weight of inch thick glass when encased will break the glass sooner or later.  Why take the risk of incorporating a material which is not of a size or nature suitable for inclusion in glass?

Instead, one alternative is to use fibre board.  Take a piece of 10mm board (or thicker if desired) and cut holes on a grid pattern.  This is done so that the whole board can be supported on steel rods for safety.  If you are using thicker board, you can insert the steel rods into the fibre board, so ensuring they cannot come into contact with the glass, but still support the whole structure.  I have done 300mm square fibre board drops without support, although the top surface is significantly bowed at the conclusion.  Because you have quite a bit of weight on the supporting board, I would include at least a couple of 3mm stainless steel rods (kiln washed)  at 1/3 and 2/3 distance across the piece, so plan your holes with that in mind.

Another alternative is to kiln wash - or coat in bead release - stainless steel rods of 3 or 4mm diameter and make the grid from them.  This grid can be supported on a rectangular frame of dams or a drop out mould.  As you are going to relatively high temperatures, bead release may work best in this situation. Lay the glass on top of the rods.

Fire your glass with the appropriate rates.  Remember in annealing that you are dealing with a piece that has pretty large differences in thickness.  You therefore need to lengthen the annealing soak, and slow the annealing cool.

Once the piece is cool, you can take it out and put it upside down.  Slide the steel rods out and gently remove the fibre board from between the “legs” of the piece.  If you have used a grid of steel rods, they can removed from the glass, by gently pulling as you twist the rods.  You may have to soak the rods in water to help soften the bead release.

Now you have a flow with no inclusions and much more likely to last.