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Any help by those that have tried it would be quite appreciated.
I've got a commission to do a wall 52"x76", of a tree with leaves, cast three-dimesionally with clay ,and then plaster/silica mold, then to fire in either 1/4" or 3/8" glass. Any suggestions on the thickness of the finished piece, if it were in one piece, vs 6 panels put together with H channel zinc?
My thought is that if I could find a kiln that would allow this to be done in one casting, it would save the cost and time of doing six molds separately. On the other hand, there is the potential that one panel might break, and it would be back to square one. And the potential for the plaster mold to break before casting also is a concern.
Would a piece this size have to be tempered, if it were to fit into a wall with a piece of tempered glass in front of it, and its away from a door, and sits 30" or so off the ground?

As we have all found, the larger the piece the more problems show up. Finding a kiln big enough, moving it, the engineering to hang it safely, and finishing it are just the most obvious. If it is in pieces you can hang each seperately and leave some "breathing" space in between, reducing the size of each. Less glass = less hassel in my view. Sounds like a great opportunity.

jerry keller wrote:Any help by those that have tried it would be quite appreciated.
I've got a commission to do a wall 52"x76", of a tree with leaves, cast three-dimesionally with clay ,and then plaster/silica mold, then to fire in either 1/4" or 3/8" glass. Any suggestions on the thickness of the finished piece, if it were in one piece, vs 6 panels put together with H channel zinc?
My thought is that if I could find a kiln that would allow this to be done in one casting, it would save the cost and time of doing six molds separately. On the other hand, there is the potential that one panel might break, and it would be back to square one. And the potential for the plaster mold to break before casting also is a concern.
Would a piece this size have to be tempered, if it were to fit into a wall with a piece of tempered glass in front of it, and its away from a door, and sits 30" or so off the ground?

Doing this in one piece is a piece of cake if the kiln is large enough. I always recommend using heavier glass. It behaves much better when kiln carving. I recommend firing to 1365 and hold for 1 hour. Plaster goes through a change at 1400 so keeping it below there is a good thing.

At the tempering facility that I use, the door opens up 1" so the glass has to fit in. It is only necessary to temper it if it is installed in a door or below 18" from the floor. I would probably recommend tempering anyway, if you do it in 1 piece. In 6, probably not.

I think you might have trouble moving a one piece mold without breaking, which might be the most compelling reason to do it in 6 molds. A one piece mold will be very heavy. You will need a BIG jiffy mixer which runs on a 1/2" drill. I think that i would try and make sections and place them on a blanket to do the one piece casting. The mold is the challenging part, not the glass, in a one piecer.

52" is wide for a kiln. Where are you located? Most of the big rigs I know of are out west.

another thought would to be to seperate the design into its components. trunk, different leafy boughs, sky,grass........big chunks. then mount them as large'tiles'. with or without some sort of grout or caulk in the seams. rosanna

ps, is this on a wall or see through? rosanna

rosanna gusler wrote:ps, is this on a wall or see through? rosanna

the piece is to be seen from both sides - it fills a hole in the wall.
it will be installed in Cleveland, Ohio

jerry keller wrote:

rosanna gusler wrote:ps, is this on a wall or see through? rosanna

the piece is to be seen from both sides - it fills a hole in the wall.
it will be installed in Cleveland, Ohio

Bruening Glassworks inc. in Rocky River Ohio has a big kiln, I'm not sure what size. Ask for Mark Konys.