Opal Art & Devit?

[Sundance]

I've never had any problems using Spectrum's Opal Art before, but the last 2 projects I've done have been ruined by what I assume is devit. The first was with "Cascadia" (which I've used for years) and today it was "Inferno" (#6076-83CC, which has swirled colors similar to the Opal Art, but is actually from their Pearl Opal series). The glass was thoroughly cleaned before firing in both cases, & the devit was only on the Cascadia/Inferno, not on the clear or opal glasses fired with it. But it was ALL OVER, not just one or 2 spots. I'll try attaching a pic, but other than one larger area, it looks like something that came out of a spray bottle ~ lots & lots of tiny matte dots. Any thoughts on why this is occurring? I love the colors, but I'm afraid to use those glasses again until I figure this out, given the amount of time & glass I'm wasting.

Here's the firing schedule I used:
200 1000 10
50 1200 60 (bubble squeeze)
50 1300 10
300 1450 4
Full 1000 10
200 950 75
100 700 0
200 120 0

Other than the spots ("How did you enjoy the play, Mr. Lincoln?") it came out perfectly. Arrgh. Thanks for your help!

(I tried adding a couple of photos, but got a Server Error msg, so I'll try posting those again later.)

[Laurie Spray]

I believe your problem is from going too slow at the top. My bubble squeeze program holds at 1250 and then fast to my finish temp. You are going too slow to 1300 which is where devit forms. I do not know how your piece is built.....but My schedule would look more like this....
300 to 1100 hold 30
50 to 1250 hold 60
400 to finish temp
9999 to 960 hold 60
100 to 850 hold 30
100 to 700 and off
Hope that helps! If you still get devit on a particular glass. Would use super spray as an insurance.

[Sundance]

Thanks, Laurie,

Is there something special about the Opal Art glasses that causes them to devit? B/c I've been using variations of that schedule for a few years now, & this is the first problem I've had. Also, I thought it was weird that none of the other glasses in either firing had a single spot, while the Opal Arts were covered with devit. I used to ramp up faster to fusing temp, but found that it was more likely to overshoot, so I slowed down that segment, since it didn't cost me much time. But I'll try your schedule & see if that does the trick.

I did try calling Spectrum to ask them if they knew what caused it, but haven't gotten an answer yet.

[Yardic Glassworks]

Curious what you are fusing the Inferno with. I don't believe that it is a glass made for fusing which makes it prone to devit.

[Sundance]

Wow Tim, you're right! I just double-checked, & Inferno's NOT System 96! Thank you so much for clueing me in ~ I have no idea how I wound up with glass that wasn't fusible, since that's all I ever look at. (Or so I thought!) That solves one problem. But it leaves me with 2 questions:

1. Is there any way to fix this project, or is it now just "learning curve" glass? Does superspray work on already devitted glass if you re-fuse it? And given that it's not nec COE96, is it even advisable to re-fuse it? Or to try to slump it, just to see how that pattern works with a particular mold?

2. I know the Cascadia is System 96, b/c I've used it many times over the past several years with this same firing schedule (& just double-checked the Spectrum website, to be sure ) This is the first time I've gotten devit. Other than trying Laurie's suggested schedule (ramping faster from 1250-fusing temp), any idea why it would all of a sudden have problems? I still think that's weird.

Thanks so much for your help!

[Buttercup]

Check the board for threads about sandblasting followed by a fire polish. That may repair the speckled surface of your project I'm sure someone can give you more specific advice on this than I can. Good luck with it. Jen

[Sundance]

Thanks, Jen. I don't have sandblasting equipment, so I might just be out of luck this time, if there's no other way to clean it off. I guess it's an expensive lesson in double-checking when you're shopping on-line, to make sure you're still where you think you are! I still can't believe I bought a piece of glass that wasn't fusible...

[Buttercup]

I've never tried this, but......would treating the surface with acid etching cream unify the surface, then it might be possible to FP it? Alternately, wait for some input from someone who knows what they're talking about!!

[Sundance]

Anyone else care to chime in before this becomes a science experiment? I figure if nothing else, it's a few more steps along the learning curve...