"bubble" panel

[Mark Selleck]

I have a customer who has asked me to reproduce a glass panel for an old china cabinet. The original is 12" x 36", 1/8" glass. The panel has a sagged pattern, basically two diamond shapes down the center (each 9"
point-to-point), with the other sagged shapes semi-circular (5" x 11") and pie-shaped. The greatest deflection from flat is in the 5" x 11" "bubbles", only about 1/8". Using the wooden door insert as a pattern, I've made a drop-out mold using three layers of 1/8" 110-J paper. I'm wondering if anyone has any experience working with 1/8" glass in a drop-out situation, and if I can get any guidelines as far as temperature and hold time to get the result I'm after. Or, do I just experiment?

Thanks for any and all help.

[Bert Weiss]

I have a customer who has asked me to reproduce a glass panel for an old china cabinet. The original is 12" x 36", 1/8" glass. The panel has a sagged pattern, basically two diamond shapes down the center (each 9"
point-to-point), with the other sagged shapes semi-circular (5" x 11") and pie-shaped. The greatest deflection from flat is in the 5" x 11" "bubbles", only about 1/8". Using the wooden door insert as a pattern, I've made a drop-out mold using three layers of 1/8" 110-J paper. I'm wondering if anyone has any experience working with 1/8" glass in a drop-out situation, and if I can get any guidelines as far as temperature and hold time to get the result I'm after. Or, do I just experiment?

Thanks for any and all help.

Mark

I work with 970 papers so I don't exactly have experience with 110J. I also work with 10mm glass not 3mm.

I would fire to 1365 and hold for 1 hour, then anneal with a soak at 1000ºF. Annealing 3mm is not much of a challenge. I would hold 6 mm at 1000 for .5 hour and take the same to go down to 900. Then 3/4 of that time down to 700 and the same down to 300. You can basically shut down and let the kiln cool on it's own for 1/8" or thinner glass.

If 1365 for 1 hour doesn't give you enough definition, you have 2 options: increase time or temperature. At some temperature the bottom will start to pick up a rough texture. Your goal is to avoid that. Tin side DOWN helps.