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Hi,
I'm planning to cut a 12" circle from the center of an old 24" by 24" by 1.25" thick mullite kiln shelf. If anyone has experience doing this I would like to know. What cutting tools should be used? How to avoid splitting the shelf? I appreciate all input.
Thanks,

Warren

Diane, One way you can avoid that problem and still use thinfire is to put 1 thickness of clear glass on the bottom of your pot melt containment. The melt drippings will fall on the soft clear glass and not disturb the thinfire. I have read this and done it a couple of times so I can't promise that ...

Tim,
Thanks. That is a terrific set up for a large bowl that is shiny on both sides.

Warren

Tim,
When you say it was a 12" drop out, do you mean that the hole was 12" and the ring edge larger or did you mean that the ring was 12" and the hole smaller?
Thanks.

Warren

Cynthia,

That makes good sense. Probably the thermal shock movement pushed it off of the edge.

Warren

Marty,
Have you been watching the weather in Portland ME? You may need 2 extra open kilns just to keep the room warm.

Warren

Patty, It looks like your disc came within 1/2 in. of the walls of the kiln. I don't know if your kiln has side elements (does it?) but that would make it difficult to heat uniformly at that rate of rise in temperature. At 2 layers (1/4 in) your disc should not have expanded and run off the edge. It...

Steve,
Of course you are correct. In my statement I was referring to the top temperature only rather than the rate of rise. That is why the real answer to her problem exists in the information requested but not yet supplied.

Warren

Tim,
1800 pieces!, wow. No wonder it is so beautiful.

Warren

How close to the edge of the shelf was your disc? How close to the walls of the kiln was your shelf? Is your kiln shelf level? Does your kiln have any side elements? Firing to 1470 (held for 10 min.) did not cause your glass to break. Glass can be fired up to 1700 or more without causing subsequent ...

Tim,
Beautiful and unique. How tall is the bowl and was it a drop out mold?

Warren

I'm thinking about putting a gloss on a slumped vase (using 3 step Karl Harron designed molds.) I have an old bottle of Fusion Headquarters "Back Magic." The idea is that this matures/glosses over at 975 F. Because the glass won't move/slump until you are over 1100 F, you can put your inve...

Thank you Michele, Jen, Joyce, Leslie, Dana, Lori for your comments, and to Brad for helping me post the last 2 pictures. It was difficult, but once I started it became a challenge just to see if I could complete it. It has all the makings of a one of a kind object. Jen's comment about a "geomo...

Three sheets of thin equals 2 sheets of standard, both are 6mm which gives a normal footprint. Chance for more bubbles.

Warren

Could you have tack fused flat, at 1350°F (+/-), and then slumped into the mold at 1250°F (+/-)? Michele, That shape is impossible to slump into. It has a deep foot at one end. Glass will fold up on itself as it slumps. Tried it with window glass first and it folded up. I actually had to fire the m...

When I first started to work with glass in '97 I made a slump mold with Mold mix 6 in what I thought was an interesting shape, like an ancient Egyptian oil lamp. Little did I know then that it was an impossible shape to slump, which I confirmed many years later using window glass. It looked possible...

Greg,
The slump will complete before you reach 1300 without a hold at 1175. Didn't realize that you were firing in a slump mold so damming won't be necessary unless you exceed 1300.

Warren

Greg, I wouldn't exceed 150F/h in the initial ramp. Don't see a need for a hold at 1175. Like Charlie, not sure 1275 will do it from a sandblast finish. I'd go to 1300 for up to 10 min. Eyeball to decide. Hold at 900 for 2 1/2 hours and drop to 750 at 90 d/hr. Off at 750. Be sure to dam it as you di...

Babette,
Thanks. That is quite a statement in glass. Worth every pound of it!

Warren

Babette,
That is a lovely bowl! How deep is it? Was it done in a single slump or using the "3 bowl" slump technique? Thanks.

Warren