Re: designing & firing a 5 layer project
Posted: Sun Feb 10, 2013 6:27 pm
Just FYI, Bulleye's posted an interesting tip on reducing bubbles between layers of glass in a stack--basically, sift a little clear powder down on the bottom sheet, top it, and fire with a bubble squeeze: http://www.bullseyeglass.com/methods-id ... power.html
I've done this inadvertently a few times and noticed how bubble-free the glass was, but never really put things together. It's a neat technique, and probably really useful for stacking multiple layers.
On the firepolish, it *is* possible to firepolish a thicker piece of glass without spreading the edges or losing its shape--I do that with small sculptures and cast pendants sometimes. But it's tricky and seems very dependent on the individual piece. Getting a polished edge on a symmetrical 5-layer slab wouldn't be that difficult, but you'd want to watch it very carefully in the kiln and be willing to accept a softened/rounded edge. Theoretically I could fire my larger sculptures that way, too, but the risk of thermal-shocking the glass is high enough that I've never tried it.
BTW, if you're grinding the edges with the standard edge-grinder (like the little spindle kind used for smoothing off sharp edges in stained glass), it may be a little rough to get a full-gloss edge polish without a lot of heatwork. The smoother the finish on your grinding, the less heatwork you'll need to bring up the gloss.
You can start with an edge grinder, then get yourself some wet-dry sandpaper in 220, 400 and 600 grit and an old sponge. Wrap the sandpaper around the sponge, dip it in water, and go to town. It won't take long, and it'll be easier to get the edge without deforming the rest of the glass. (You'll still have to go slow and watch carefully, though)
I've done this inadvertently a few times and noticed how bubble-free the glass was, but never really put things together. It's a neat technique, and probably really useful for stacking multiple layers.
On the firepolish, it *is* possible to firepolish a thicker piece of glass without spreading the edges or losing its shape--I do that with small sculptures and cast pendants sometimes. But it's tricky and seems very dependent on the individual piece. Getting a polished edge on a symmetrical 5-layer slab wouldn't be that difficult, but you'd want to watch it very carefully in the kiln and be willing to accept a softened/rounded edge. Theoretically I could fire my larger sculptures that way, too, but the risk of thermal-shocking the glass is high enough that I've never tried it.
BTW, if you're grinding the edges with the standard edge-grinder (like the little spindle kind used for smoothing off sharp edges in stained glass), it may be a little rough to get a full-gloss edge polish without a lot of heatwork. The smoother the finish on your grinding, the less heatwork you'll need to bring up the gloss.
You can start with an edge grinder, then get yourself some wet-dry sandpaper in 220, 400 and 600 grit and an old sponge. Wrap the sandpaper around the sponge, dip it in water, and go to town. It won't take long, and it'll be easier to get the edge without deforming the rest of the glass. (You'll still have to go slow and watch carefully, though)