The new pieces that turned out wellNow that my kiln was back in place and I could start to fuse glass again, I put my first load into the kiln on Sunday afternoon. When I opened the kiln on Monday afternoon, I had a serious shock - two of the pieces didn't make it through the fusing process!
Molten glass sticks to just about anything, so a release agent is necessary to keep the molten glass from sticking to the kiln shelf as it goes through the fusing process. There are two ways of protecting the shelf from the glass sticking to it, shelf paper and kiln 
The broken triangle bowl blankwash. Kiln wash is a powder mixed with water that is painted onto the kiln shelf, building up several layers to create a barrier. Shelf paper is a barrier that comes in rolls in varying thickness, from truly paper thin, all the way up to shelf blankets of about 1/2" thickness that can be used to form glass in different ways. Both accomplish the same thing, but rolls of shelf paper are pretty expensive compared to the cost of kiln wash. Now that I was working in bulk - seven fused pieces were in this batch - I thought it was time to convert from shelf paper to kiln wash.
So this firing was the first time I was using kiln wash instead of shelf paper to protect the kiln shelf from the glass. I had put down 4 layers - the package directions only call for 3, but I didn't want to take any chances - layering the washes horizontally, vertically, and in each diagonal direction on my kiln shelf. Despite the extra layer, there were two spots - one on each of two separate pieces - where the glass had stuck to the shelf and caused friction as the glass heated and cooled and those spots were where the glass had fractured.
Heart shaped bowl blankLive and learn, I suppose... but it was very disappointing after having added the extra layer of kiln wash to be on the safe side, to say the least. At any rate, I've put an extra layer of kiln wash on the molds that I'll be using to turn the remaining two blanks into their bowl shapes. Hopefully, that will work. I've put three layers on the other molds that I've used in my past fusing efforts, but now I'm feeling a little paranoid.
For those of you who aren't already familiar with glass fusing, it's a two step process if you are making a decorative glass plate or bowl. First you cut and layer glass to form a blank in the shape of the piece that you're creating. I used a combination of a piece of decorative art glass for the bottom layer, then added fusable glass paint, glass frit (ground glass that comes in varying sized material from a powder to a coarse chunk), stringers (glass rod pulled into a very thin string 1/16" or less in diameter), and laser cut pieces of dichroic glass (glass with a layer of misted minerals applied in a process that causes beautiful effects where the light changes the color of the glass when viewed from different directions), and a clear glass layer on top to add depth and dimension.
Once the sandwhich is fused together to form the blank in the specified shape and size to fit a mold, it goes through a separate firing at a lower temperature where the glass melts just enough to form itself into to the bowl or plate 
The broken square bowl blankshape. This is referred to as slumping. So, once the layers of kiln wash are dry on the molds - the process takes time as the kiln wash needs to dry between each coat - I'll be putting my two bowls back into the kiln for the slumping process, which will probably be happening overnight tonight.
These images show both the sucessful efforts as well as the two fractured blanks that didn't make it. To make it even more disappointing, those were my first two efforts with the fusable glass paint, as well as my first efforts for those particular shapes. But at least these pieces do give me a feeling for how the glass paint looks after firing.
Closeup of one of the pendants from the photo aboveThe smaller pieces will be pendants, so they won't be going back into the kiln again - they're done. All they need is a little sanding to take off some rough edges from the firing process and getting a bail glued on. (The bail is the jewelry finding that allows the pendant to hang from a necklace.) I just tucked the bails in place under the piece for the photos, but after looking at them, I think that the ones I used for the photos don't look substantial enough for these particular pendants, so I need to go through my stash looking for some more appropriate bails to use. I think I know just what will work, the hard part is finding them... Wish me luck!
Tuesday, July 26, 2011 at 12:55PM 
