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Glass sticking at high temperatures

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Glass sticking at high temperatures

Postby sharol07 » Fri Sep 28, 2018 3:26 pm

Hi. I’ve been working with wire melts for about 10 years. I always melt the glass into a fiber lined form and onto a base sheet of teckta 3 mil. Recently, I've started to use Bullseye 2 mil for the base glass. I’ve done this 3 times and my 1st attempt worked perfectly, but the last two have completely stuck to the shelf and cracked uniformily into a kazillion pieces.

My schedule is tried and true, no past problems. My top temperature is 1650 and I use Hotline High Fire kiln wash, applying 8 thin layers 1:5 ratio. My shelf is thoroughly dry before firing. I always sand and reprime my shelf after every use.

I have thought about using a thin irid as the base, but I would first like to understand what’s going wrong. I suspect that the thinner glass is the culprit, getting too hot before the melted glass above is flowing, but that doesn’t explain why my 1st attempt worked just fine.

Thanks to anyone who can help with this.

Sharol
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Re: Glass sticking at high temperatures

Postby jestersbaubles » Thu Oct 04, 2018 6:57 pm

Personally, I would never use anything besides Bullseye kiln wash (or Zyp, depending upon the mold). I've had very poor luck with Primo and other kiln washes. Hotline is rated "up to 1550 or higher", so the kiln wash may be failing.

Dana W.
Dana Worley Fused Glass Designs
dba Jester's Baubles
http://www.jestersbaubles.com
http://www.jestersbaubles.blogspot.com
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Re: Glass sticking at high temperatures

Postby sharol07 » Sun Oct 07, 2018 7:12 am

Thanks, Dana. I appreciate your input.

The wash I’m using is Hotline Hi-Fire. It’s formulated specifically for temperatures above normal fusing temps., such as combings and melts. I’ve used it successfully for over 10 years. The only difference in my layup from that of years past, was that I was using thin Tekta rather than standard 3 mil.

Curiously, I recently replicated my last failure layup (same weight and colors of glass) and melted directly onto a kiln washed shelf, no Tekta base at all. It turned out with minimal sticking. There was just the typical wash I had to blast off.

My conclusion is that the thin Tekta experiences too much heat work before the glass in the screen melts onto the shelf, adding mass and insulation to the shelf. I believe this accumulated heat work was causing the wash to breakdown.

Just my opinion.

Sharol
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