Can I slump directly on a kiln shelf without a mold?

[Marian P.]

I'm pretty sure I can do this but thought I'd run it by "the experts". I have two large pieces to slump into an organic shape. I only have one mold and don't want to fire my big kiln half empty. So I was thinking about putting some fiber blanket under the parts I want to stay elevated and then just slumping the rest directly onto a kiln shelf. They are two large "coral" pieces so don't need much of a slump. Any reason I shouldn't do this?
Thanks!

[Warren Weiss]

No reason to not do it. Be sure there is some folded fiber blanket under the raised parts so that the blanket doesn't flatten out during the slump. Calculate your annealing time for the piece in the mold because it will cool slower than the piece over the fiber blanket.

Warren

[Kevin Midgley]

uneven heating of the kiln shelf may result in it cracking. Cover half the shelf and watch it break.

[Judd]

I fire and slump on the floor of my kiln all the time.
1) Cover the floor with kiln wash (which you should do anyhow in case of an accident).
2) Extend your anneal time.

[JestersBaubles]

I have slumped platters where the two short edges are placed on fiber-paper covered kiln dams, and then allow the glass to slump to the kiln-washed or fiber-blanketed shelf.

Dana W.