Looks good Dave.
Your glass piece appears to be about 1/4" thick. I bring my glass up to bending temperature in about 2 to 2.5 hrs. on a piece
that size.
Saves on electricity and speeds the job. I know that you don't want to thermal shock and break a piece that you
have spent hours etching, engraving or chipping, but a single layer of glass can be warmed reasonably fast as long
as it heats up evenly.
I allow it to soak at the bending temperature until I see the outter edge of the curve contact the mold. I remain holding
at that temperature just until I see the reflection of the heating elements become nearly straight/flat accross the trough of the bend
(but before the central area of the glass contacts the mold, causing pits or dents) This way you get a even plane on the bend and
avoid the "saddle" or "swoop" at the ends.
When the glass reaches the proper point, I do not "crash cool" the kiln, but rather crack open the top several times, while watching the pyrometer to stop the bending action. (Venting too quickly will stress the kiln and you will hear it "talk" with a kind of cracking sound. Not good!)
After stopping the bending by venting, I generally just allow the kiln to cool by itself. If I'm in a rush, I will sometimes place a 1/4" metal
rod accross the front of the kiln to hold the lid open 1/4" to speed cooling. I have used a glass cutter to cut glass that I have bent in this
method, and it always cuts perfectly, proving that it has been properly annealled and is not under stress from the proceedure.
By the way, are you protecting your precious eyesight while peeking into your kiln?? At higher temperatures the coils in your kiln will
give off infrared rays that will damage your eyesight. The damage is cumulative and can't be healed or repaired.
I bought a pair of protective glasses from a company here in the US called Aura Lens Products, Inc. (
www.auralens.com)
They are a light shade of green so you can see your work, but shield out the infrared waves. Let me know if you can obtain a simular
pair over there, or I can get you a pair over here.
Denver Chapter of the Letterheads
