Dang bubbles

[Aglassygirl303]

So, nice piece of Opal glass simply cut in a 10x8 rectangle. Bubble everywhere.
Here is my schedule

DPH-temp-hold
300-1000-10
100-1225-30
200-1250-25
300-1425-10
999-960-60
150-700-5
999-100-done

Little bubbles like pimples Otherwise pretty

Here was the original fuse sched

300-1250-45
300-1450-10
999-960-60
150-700-5
999-100-0

Had same little bubbles so I added slower ramp and another bubble squeeze.
Help

[beninfl]

A single 3mm piece of glass, or was it two 3mm sheets for 6mm total? If one sheet, that's the problem.

Other than that, was the kiln shelf with kiln wash dry? If not, bubbles.

Do you have a picture of the bubbles? That will help a lot, too.

Change the 300 DPH to 1425 to AFAP to 1425. No reason to go at 300 and chance devit scum. This wont help with the bubbles, just will help overall.

[Aglassygirl303]

Standard two pieces of 96coe glass fused together.
Kiln Shelf is a Kaiser Lee Board lined with fresh thin fire paper

I have never had devit, except for when my thermocoupler was sticking inside the kiln wall around 4 inches. But otherwise never.

[Aglassygirl303]

I tried to post a picture but too big to upload, The glass is perfect and smooth but there are very small bumps, like it has pimples or boils. They are not even but there are many. I seems to happen on the streaky glass or the opals, not on solids. This is new. I have worked many times with both of these glasses. I wonder if my glass dealer is selling "seconds" I do see some pits in the pieces I have not fired yet. Could that be an issue?

[beninfl]

You can always send the image to www.imgur.com and then paste the link here....

[rosanna gusler]

A single 3mm piece of glass, or was it two 3mm sheets for 6mm total? If one sheet, that's the problem.

Other than that, was the kiln shelf with kiln wash dry? If not, bubbles.

Do you have a picture of the bubbles? That will help a lot, too.

Change the 300 DPH to 1425 to AFAP to 1425. No reason to go at 300 and chance devit scum. This wont help with the bubbles, just will help overall.

the water in a not dry kiln shelf is way gone before the glass is soft .

[JestersBaubles]

Here is my schedule

DPH-temp-hold
300-1000-10
100-1225-30
200-1250-25
300-1425-10
999-960-60
150-700-5
999-100-done

Help

Slower ramp from 1000 up to 1225 -- 50 deg/hr.
Longer hold at bubble squeeze -- 60 minutes.

I typically ramp to 1100, hold for 30, then ramp to 1225.

2 cents,

Dana W.

[rosanna gusler]

i like a hold at 1100f as well. things just go better over all if i spend 20 or so min there.

[Aglassygirl303]

Thank you, I will try that.

[DonMcClennen]

Bubble squeeze should be combined with "chads" to work as planned.

[Aglassygirl303]

What is "chads"

[RachelM]

A chad is a little piece of glass, that you use at the edges of the two layers of glass to help air escape during the bubble squeeze. It allows the center of the piece to start to fuse before the side do; as if the sides fuse first, then air, ergo bubbles, get trapped in the middle.

Chads can be a single piece of frit, a piece of stringer, or a piece of scrap. Depending on the placement, you might need to do some coldworking at the end to smooth the edges where the chad was placed, or not.

Other ways, as mentioned above, to get rid of bubble, is a long, long bubble squeeze.

Having said all this, I did some tiles around Christmas for some family gifts; I did a long, long bubble squeeze, and also got pimples, or abcessess, as I called them. I would not call them bubbles, but the glass rose up in certain spots, it didn't look like a bubble as much as it looked like a bad pimple coming to the surface. Someone else suggested to me it might have been the glass (Bullseye Stiff Black).

Hope this helps!

Rachel
imaglassydiva@aol.com

[Aglassygirl303]

RachelM, really funny you should mention the glass. I have been fusing for 8 years, always have used Spectrum System 96, that is what I learned on. I have had the same Kiln and used the same schedules for the same sizes and shapes. Suddenly I am getting these bubble?!?!?! Small and larger pieces. It has been making me nuts. So I am looking at the glass last night and there are little pecks all over the surface. I have purchase my glass from the same person for a while too. I have never had any reason to inspect the glass but I may be doing that now. I just wonder if she either received a bad bunch of glass or perhaps she purchase seconds? Is that even possible to get a bad batch of glass?

[beninfl]

I always thought chads were those things that hang from ballots here in Florida.