kiln for slumping q?

[wynpotter]

I have seen where some glass fusing/slumping kilns are designed with elements in the lid of the kiln. My kiln has 3 zone type s thermocouples that I use in my pottery glaze firings.
Is there an advantage to kilns for glass fusing/slumping or a major disadvantage in using a kiln with side and a bottom element.
My kiln is a extra insulated high temp with a Bartlett controller with programmable 6 ramp control.

I can't see where the overhead element would be required unless I'm missing something.
Thanks for the help
Wyndham

[Brad Walker]

You can fuse without an element in the lid. Lid elements help even out the heat in the middle of the glass compared to the sides, but if you don't have them you can still fire with your pottery kiln. Just go a bit slower from room temperature to 1100F than if you did have lid elements

[Bert Weiss]

The more evenly you heat the glass, the faster you can do it without cracking it. Kilns with perimeter elements heat the glass closer to the elements before they heat the middle. When the glass is flat and parallel to the elements, if the glass can directly "see" an element, it can heat that glass quite quickly, causing a crack. Baffling can change this paradigm. Raising or lowering the height of the shelf can also change it.

If you were reheating a small diameter 36" tall glass vase in a 3 zone, perimeter element kiln, you could do it faster than in any other configuration.

So, yes you can fire any glass in a perimeter element kiln. You will have to learn for yourself, what speed at which to proceed. Be forewarned, we constantly get people saying, "this schedule has always worked for me, so why did the glass crack this time?