Is this devit?

[Joel Taylor]

This was my fourth time firing and I'm trying to familiarize myself with the full fuse fire schedule and figure out how big of a piece I could fire in the kiln. I tried to keep it simple and use as much uncut glass as possible, so there were 4 - 12" x 12" tiles and 2 - 12" x 3.5" panels on either end. The tiles with more opal were on top, more translucent on the bottom.

Problems:

Bubbles that were about 3/8" diameter. I washed with soap and water, maybe I didn't rinse well enough.
Unsure if the surface finish/texture on the back of the glass is normal or if I can remedy the situation.

Equipment:

skutt gm1414 (top and side elements)
kiln washed shelves, 2" posts (no fiber paper)
spectrum baroque glass - 2 layers of 3mm, total area = 12"x31"

Fire schedule:

Temp (deg C) Rate (deg C/hr) Hold (hr.min)

0 - 540 90 0.0

540 - 600 135 1.0

600 - 835 470 0.25

835 - 540 AFAP 3.00

540 - 490 13 4.00

490 - room 96 5.00



Thanks

[Laurie Spray]

It is hard for me to tell from the pictures if there is devit......i do however see the bubbles.

I can't read your schedule unless it is translated to F. So I am no help there.....
Did you do a bubble squeeze? Spectrum glass is so flat you should not be getting these bubbles if fired correctly.

[Kevin Midgley]

baroque isn't flat. Air bubbles are likely.

[Joel Taylor]

Sorry about that, I got the schedule from "Warm Glass: A Complete Guide to Kiln-Forming Techniques". They don't specify a 'bubble squeeze' phase, I hadn't seen it mentioned until I came to warmglass and I just figured I'd try the schedule from the book first.

As far as the Spectrum; one of the sides was definitely more contoured, it follows the streaky part of the glass. I stacked the layers with the smooth sides together, which I had assumed was the correct method, not for sure though.

Schedule in deg F:

Temp (deg F) Rate (deg F/hr) Hold (hr.min)

0-1004 200 0

1004 - 1112 242 1.0

1112 - 1535 850 0.20

1535 - 1004 AFAP 3.0

1004 - 914 22.5 0

914 - room 169 0

[Joel Taylor]

It might be worth mentioning that I have to use three different sections make up my shelf and the entire surface wasn't flat. I didn't notice until afterwards, but it caused a 1/8" ridge to rise on the bottom of the glass, very near to where there is a concentration of bubbles.

[Laurie Spray]

Joel....The only way to fire across a 3 section kiln like that and not have a ridge is to either
Get a full board of fiber board and cut it to the size of your kiln
Use a blanket like I think Bert does
or avoid the cracks

as far as the schedule

this is yours so I could read it////
200 degrees an hour -1004 hold 0
242 degrees an hour to 1112 hold 1hr -
850 degrees an hour- 1535 hold 20 too hot way way too fast -- no bubble squeeze
AFAP to 1004 AFAP 3.0 anneal for 96 is 950
22.5 degrees an hour to 914 hold 0
169 degrees to room 0

are you sure you are doing the conversion correctly?
just about everything is wrong with this schedule......
sorry....nice kiln though!!

I would go:

300 degrees an hour to 1150 hold 30
50 degrees an hour- 1250 hold 45 (bubble squeeze)
450 degrees an our to 1460 hold 5 min
9999 to 950 hold 1 hr
100 degrees an hour to 850 hold 30 min
100 degrees an hour to 700 no hold....off
let kiln cool naturally

Hope this helps.....sorry I am lousy at using Cent

[Joel Taylor]

I'm pretty sure the conversion is correct, sorry about the formatting. I'll attach a pic of the chart i used, hopefully it's readable. There was an additional chart to add time for larger pieces, etc., so I probably just misinterpreted or miscalculated something. Of course Cent isn't my native language either, so theres always that.

Thanks for your help, I think i'm going to find a reference for a schedule on warmglass and keep the size of the work small enough to fit on the shelf.

[Marty]

Also be aware that Spectrum's Baroque is not always compatible, not even with itself, as there are viscosity issues on top of the COE.

[Joel Taylor]

Thanks, I saw several postings regarding that when I searched the site. I didn't know too much about the glass before I fired, I assumed it was the same manufacturer/model/COE. I got these in a variety pack a while back and I didn't really like the way they looked, but I assumed it would be compatible and it was the only stock I had that could run the length of the shelf. Of course, it turns out to be a glass that can sometimes not even be compatible with itself.

[Marty]

Joel- I made several strip cut pieces out of baroque a long time ago after testing the sheets against themselves and each other (and finding no COE distortion with polarized lenses). One of those is slowly coming apart in my studio. The others got sold but no one's complained yet- I fully expect to have to refund their purchase price if they find me.

[Laurie Spray]

Really Marty.....that is disturbing!

[Kevin Midgley]

pretty logical when you think about it and the huge thickness differences between the clear and the colour. The only way to get them is by using viscosity which is one component of the compatibility conundrum.
Fired a whole lot of that stuff in the days before 96 but never tried full fusing it.

[Joel Taylor]

Thanks Marty, it's like you could hear me getting ready to cut it up and use some of the salvagable pieces.

[Stephen Richard]

This was my fourth time firing and I'm trying to familiarize myself with the full fuse fire schedule and figure out how big of a piece I could fire in the kiln. I tried to keep it simple and use as much uncut glass as possible, so there were 4 - 12" x 12" tiles and 2 - 12" x 3.5" panels on either end. The tiles with more opal were on top, more translucent on the bottom.

Problems:

Bubbles that were about 3/8" diameter. I washed with soap and water, maybe I didn't rinse well enough.
Unsure if the surface finish/texture on the back of the glass is normal or if I can remedy the situation.

Equipment:

skutt gm1414 (top and side elements)
kiln washed shelves, 2" posts (no fiber paper)
spectrum baroque glass - 2 layers of 3mm, total area = 12"x31"

Fire schedule:
Conversions for those who can't use the little tool that Brad has provided for us at the top of each page - i.e. no excuse for anyone to say they can't read F or C temperature.
Temp (deg C) Rate (deg C/hr) Hold (hr.min)

0 - 540 1005c 90 162/hr 0.0

540 - 600 1113c 135 243/hr 1.0

600 - 835 1535c 470 847/hr 0.25

835 - 540 AFAP 3.00

540 - 490 915c 13 23c/hr 4.00

490 - room 96 173/hr 5.00



Thanks

You don't indicate how thick the tiles were at the start - maybe one layer?
You initial rate of advance is much slower than needed. You could go at 220C/hr (for up to 6mm thick) to a bubble squeeze around 630-650 (for S96).
795C or 800C is high enough for Spectrum. Your bubbles may come from thin or over-fired glass or both.
In the days when I messed around with spectrum, I found baroque very prone to devit.
The annealing point for S96 is about 513C and 30 minutes would be enough.
80C/hr to 370 would be an appropriate annealing cool rate.
Spectrum transparents are pretty good for fusing, but the opalescents, wispies, and Baroques are not so good. The transparents all are fine for finding out how glass reacts in different firings. But do not expect fine work from glass that is not tested compatible.

[JestersBaubles]

Really Marty.....that is disturbing!

So by "baroque" I am wondering if Marty is referring to the baroque art glass (not S96).

(which would not be so disturbing... )

Dana W.

[Marty]

The glass I used probably preceded System 96. Spectrum now lists Opalart as fusible but doesn't mention Baroque- have they just renamed it (and fixed the viscosity issue)? I'd still recommend doing one's own tests before committing to a sizable project.

[Stephen Richard]

Baroque is not a tested compatible glass. They do have a wispy S96 glass that has some similarities to the swirls of baroque.

[Havi]

Even though everybody can undestand it,
I would like to point out that the temprature that is marked as C [centigrade / Celsius] Is actually FARNHEIT.

Please note,


Havi