Following my recent post a fellow former apprentice from Berea, Naomi Sellards, requested that I post some photos of what the green bottle glass looked like after it is fired. I put the chunks of green wine bottle glass on the pieces before they are bisqued. The glass does not melt at all in the bisque, it anneals a little, but doesn't melt. This also avoids applying the glass with glaze (post-bisque) and crossing your fingers that the glass stays on the piece during the firing. From experience, I will say that I don't recommend doing this unless you are putting it on top of a handle or horizontal surface. Otherwise, the glaze, which you thought would hold the glass on, fluxes before the glass fluxes in the final firing and drops the glass (or so it would seem, I could be wrong as to what exactly it does in there). Also, putting the glass in it when the ware is green leaves a neat impression on the piece after the glass melts in the final kiln.
Green bottle glass pressed into green ware
As I mentioned in the previous blog, I'm a devotee of green wine bottle glass. I have tried other kinds of glass. I did some experimenting with this when I was at Berea. I don't have any photos of what happpened with the brown bottle glass, but it basically would leave these nasty pink crizzled streaks on the piece. I think there was either an impurity in the brown glass, or it just didn't like salt.
Nice collection of melted glass in the texture of the mug
A little crystallizing!
I don't put large chunks on because depending on where it is in a wood kiln, the glass can get really out of control! Either way, I really like how the glass pools on the textured surface of the newer pieces I have been making. I'm willing to do some grinding if I have to. I've heard other potters such as Mark Hewitt use pure glass pieces, or frit, for their glass source. Some people I've talked to have used beads from a craft store. My experience with beads from a craft store was not good (especially blue beads) as the surface crizzled and didn't look good. I think it must have something to do with the level of purity that the glass is. I could be completely wrong, and if any of you know better than I, please do let me know! In the meantime, I'll stick with green wine bottle glass.
I have quite a few pieces with glass in them (hopefully) going in a kiln in the next month. I'll be sure to post photos of their outcome!