Can I double up

[Vicki M]

My kiln is 11" deep. My question is can I put 2 shelves in to fuse glass at the same time. If I put a 1" stilt under the bottom shelf and then another 1 or 2" stilt to hold the next shelf on top of the first shelf would this work or not?

Thanks,
Vicki

[jim burchett]

In my experience No. You may be able to fuse on the top shelf and slump on the bottom shelf

[Morganica]

I agree with Jim. The extra shelf, furniture and glass mass become a baffle that keeps heat from reaching the bottom shelf, while the top shelf is closer to the elements and gets more heat. The top piece is liable to boil while the bottom piece barely softens, and annealing times can become an issue because the top loses heat a lot faster than the bottom.

If you keep a goodly amount of airspace between shelves the problem isn't so bad, but if the kiln is only 11 inches deep there's not a heckuva lot of room to begin with. If you experiment quite a bit you'll come up with a schedule that gives you a bottom slump and a top flat fuse...but more than likely you'll have to slow down the schedule, and by the time you've done all that it's probably faster to simply use two firings.

There ARE times when stacking works wel, such as when casting with small, open-faced molds. You're firing for a longer time, you don't have to worry as much about overheating the glass, and you can lengthen the schedule to accommodate the heat differences without too much fuss.

[DonMcClennen]

Someone said..."glass needs to see the heat, ceramics only needs to feel it"..I think the statement is accurate.

[Vicki M]

Thanks everyone, I guess it doesn't hurt to ask. It seems a shame for all that extra space to be wasted