Suggestions on what I'm doing wrong?

[chneos]

Open to all tips - please!!!
I'm fusing powders (or trying to, anyway) and not having much success. Here's the image pre-firing.
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pre-firing

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It's all 96, fused in an 8 inch Evenheat kiln. The second image shows both (failed) fired attempts. When I fired Betty (1st attempt) on the right, I failed to vent the kiln, and took it up to 1345 degrees. When I fired Betty (2nd attempt) on the left, I used the following schedule in a vented kiln:
315 to 1320 for 11 min; AFAP to 950 for 40 min; 200 to 750 for 15 min; 300 to 400, kiln off.
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2nd and 1st attempts fired

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I'm fusing all (layers of powders) at once (in one firing). Initially, my thought was too hot, which is why I backed it down to 1320, but my second attempt still appears 'charred' and it has more of a mat, bumpy, low-fired finish.

I have had success with this technique before, although can't figure out what I did differently then verses now. Here is an example on slumped bottles using coe 82 powders (one somewhat successful, one failure). I realize the breaking of the 2nd (cobalt) bottle was a ramp issue ... but what's causing the powders to 'char' and 'burn'? [BTW the bottles have only one layer of powders, unlike the Betty Boops.]
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slumped bottles with powders

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Please help ... Thanks, Kris

[Morganica]

From the looks of things you're combining powders that react with each other. Glasses that contain silver, lead, and copper will react with glasses that contain sulfur or sometimes selenium. Typically, where those glasses touch you'll get a "bloom" of dark color. The exact shade of the reaction depends on what's combining, and if there's a lot of the reactive chemicals present, the glass doesn't even need to be touching to react.

It's hard to tell what's in the every glass unless the manufacturer tells you, but unless you know otherwise, assume that:
--Cool blue/blue-green/aqua/turquoise glasses contain copper
--Cool pink, magenta, red-violet and some pinky-white glasses contain lead
--Hot-colored glasses such as yellows, oranges, warm reds, ambers, and sometimes warm yellowish neutrals (vanilla-colored) contain sulfur/selenium

The reaction will be strongest where the powders are most-fused into the glass. If you tack-fuse the glass won't be fusing long enough for the reaction to complete, so you'll get only partial darkening.

My first encounter with reactivity was similar to yours--I did a big portrait, entitled "Ice Maiden," on a creamy vanilla base. I added a bit of pink and amber powder to warm it up. When she came out of the kiln, she was a nice, toasty brown. I named her "Tropical Maiden."

So...I'd ask the manufacturer for a list of reactive potentials for the glass you're buying. Then either don't use those glasses together, or put a thin layer of clear between them so that they don't actually touch.

[chneos]

TY Morganica ... That's something I hadn't considered. Would I reach the same charred/burnt ending if I fired each layer independently? As a chemical reaction, it probably wouldn't make a difference, right?

Hmmm - "Smokin' Betty" ... maybe not

[Morganica]

If you fired them separately and then glued them together, yes. But any time the glasses get hot enough to fuse while touching--even if previously fused in separate steps--you'll get the reaction. You either permanently separate them with a different layer of glass, or swap one of the colors for another that doesn't react.

I haven't worked much with fusible float, so I don't know for sure that's what happened, but it looks suspiciously like it.

[Kevin Midgley]

glue or thinfire burnout without ventilation

[JestersBaubles]

glue or thinfire burnout without ventilation

ThinFire without ventilation? Really? I don't think so -- that's a pretty severe reaction going on there.

I am extremely lucky, or ThinFire/Papyros does not cause all the problems attributed to it .

Dana W.

[Kevin Midgley]

different kilns, different firing conditions, different glass, different glues,different powders ...... different results. I was just pointing out the variables that could be causing a problem.
Maybe you've been lucky but I've had similar results when firing with organics present. The last I heard kiln shelf paper is organic.

[Morganica]

Have to be an awful lot of glue to cause that much brown, I'd think...especially through opaque glass.