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Help! I am trying to slump a 6" square ashtray, Spectrum Baroque & 100SFS. The trouble is slumping the very small areas where the cigarette would rest. For larger pieces I usually slump at 1250 for 10 minutes, this small piece does not even start to slump at 1250. I ended up slumping at 1325 for 30 minutes, and I had a nice slump in the middle put the small areas only came half way down. It looks OK, but I'm real particular about products we sell to retail stores. Holding at 1325 for that long dulls my glass. (I know we could use clear gloss, but if I did this right the glass should stay as shiny as when I fused it). Any ideas?
Rich Edelman KILN-TEC

Just curious, you've had success fusing Baroque & 100SFS?

Jack

Rich,

Bend a piece of 1/4"Ø stainless steel rod with a short 90° bend at the end and a long handle and coat the short end with Boron Nitride. At your peak temp, when the rest of the piece is slumped, reach in and press the glass into the groove with your coffin-nail groover tool.

Tony

KILN-TEC wrote:Help! I am trying to slump a 6" square ashtray, Spectrum Baroque & 100SFS. The trouble is slumping the very small areas where the cigarette would rest. For larger pieces I usually slump at 1250 for 10 minutes, this small piece does not even start to slump at 1250. I ended up slumping at 1325 for 30 minutes, and I had a nice slump in the middle put the small areas only came half way down. It looks OK, but I'm real particular about products we sell to retail stores. Holding at 1325 for that long dulls my glass. (I know we could use clear gloss, but if I did this right the glass should stay as shiny as when I fused it). Any ideas?
Rich Edelman KILN-TEC

Rich

You could try coating with borax and firing to 1400ºF

Jack:
We have been fusing Spectrum 100SFS, Baroque, & System96 since March, so far so good. The non-96 glass wants to devit so I use Fusion HQ (Gil Reynolds) Clear Gloss and changed my firing schedule to travel quickly past the devit range. You do need to check compatability & check with a polarizer.

Tony:
Thanks, I will try that trick the next time I slump, sounds good.

Bert:
If I go to 1400 while slumping will that give me stretch marks on the glass? I've had trouble before when slumping too hot for too long.
Thank all you guys, much appreciated,
Rich Edelman KILN-TEC
http://www.kilntec.com

Just curious if you have really tried any of your ashtray in actual use. I'm thinking thermal stress and broken ashtrays from hot butts.

Ron

Ron Coleman wrote:Just curious if you have really tried any of your ashtray in actual use. I'm thinking thermal stress and broken ashtrays from hot butts.

I made one for my father five or six years ago that's still going strong -- and he smokes pipes and cigars.

Ron Coleman wrote:Just curious if you have really tried any of your ashtray in actual use. I'm thinking thermal stress and broken ashtrays from hot butts.

Ron

I use homemade ashtrays all the time - never had one break from a cigarette yet. But, I did have one of my Dad's old glass ashtrays from back in the 50's crack right in half just from letting a cigarette sit in it. I never saw him without a cigarette, so I know he used this one (and every other one in the house) all the time - but for some strange reason, it cracked right in half one day as a cigarette sat in it. It was a beautiful ball shaped royal blue piece with lots of bubbles floating around inside and the glass was at least an inch and a half thick. I'd trade a bunch of my homemade ones to have this one whole again!

Jackie

I remember a beautiful glass ashtray that my mom bought back in the 50's. It was made by Elwood Glass in Elwood, Indiana and had what looked like red flowers inside and elongated bubbles. It sat on the buffet in the dining room and no one ever used it. One day it just broke in half, I guess from some hidden stresses.

The matching paperweight she bought the same day is still going strong.

Ron

Ron Coleman wrote:I remember a beautiful glass ashtray that my mom bought back in the 50's. It was made by Elwood Glass in Elwood, Indiana and had what looked like red flowers inside and elongated bubbles. It sat on the buffet in the dining room and no one ever used it. One day it just broke in half, I guess from some hidden stresses.

The matching paperweight she bought the same day is still going strong.

Ron

Ron

That is a basic expansion example 101. The red flowers are higher expansion than the crystal around them. In the flat ashtray the stress caused the glass to split in half. In the spherical paperweight, the higher expansion glass puts the whole piece in a state of compression which makes it stronger. The stresses are sucking in on the spherical shape which can handle it.

We who are making flat work need to use more closely compatible glasses.

The stresses caused in one's lungs by expanding smoke are a similar but different issue. cough cough