Whaddya think happened to this?

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Milbrose
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Joined: Sat Nov 06, 2010 10:49 pm

Whaddya think happened to this?

Post by Milbrose »

Hi everyone
I had a surprise when I opened the kiln this morning.. this poor decapitated snowman... I am assuming this happened on the upside of the fuse as the edges are nicely rounded. The client wanted this nice cute little snowman tray and he ... well you can see what misery has befallen him...

this is bullseye glass and I am in the office so don't have my schedule handy but its one layer with the decorations ... went up to 1480 am actually pleased with the fuse itself except for this bizarreness...

thoughts would be appreciated as I am going to pull together another one and try to get it in the kiln tonight ...

thanks
Shalva
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snowman.jpg
Kevin Midgley
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Re: Whaddya think happened to this?

Post by Kevin Midgley »

speed kills. add scarf to design to fill gap
Bert Weiss
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Re: Whaddya think happened to this?

Post by Bert Weiss »

Thermal shocked during the heatup, then fused together at top temp. The thermal shock was relatively strong. Strong enough to fully break apart and move that far away. Which means you were going way too fast.
Bert

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Morganica
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Re: Whaddya think happened to this?

Post by Morganica »

I like the idea of the scarf design. You've got a single-layer base with hard white glass tack-fused on top and some softer black elements scattered about--was this a second firing?
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Lauri Levanto
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Re: Whaddya think happened to this?

Post by Lauri Levanto »

The answers above I trust.
In addition I made an interesting observation.

The shock was strong, moving the base glass apart.
It seems to me that it happened at the upper range of initial warm up.
As I understand your picture, the head was not yet fused, and slid into the break. The arms were fused and stretched over the break.

What does it tell? The black glass softens much earlier than white.
A nice demo. May I get your permission to use the picture on my web tutorial in Finnish?

What can be done. If the head is fused on both parts, as I see it, the gap is there to stay. You may add another clear sheet under to make it double thick, or you have to fill the gap. It forms a nice and useful horizon line. You need quite a lot of frit to fill it. It is better to be f.ex. green that fuses early. You need a pile of at least 5 mm high to get a 3 mm fill. Otherwise there will be holes in it.

Next time slow sown.
Speed kills. Haste is an invention of Devil, says Havi
-lauri
Milbrose
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Re: Whaddya think happened to this?

Post by Milbrose »

Thanks everyone... I appreciate your input and will slow down my schedule... in hindsight after hearing what you have all said... I think the size of the piece impacted it... as I was in a hurry (speed kills) and didn't adjust the firing schedule for the size of the piece and I just hit the darn user number with a full fuse schedule that had been used for a small ornament... obviously fine for something small, not so much for this ... so I will throw another one together tonight and slow my schedule way down on increase, I knew that the increase was the problem.... so thank you so much

and yes of course use my picture for your tutorial by all means...

I appreciate all of your help
thank you
Lauri Levanto
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Re: Whaddya think happened to this?

Post by Lauri Levanto »

As I mentioned, the black is softer than the whitw.
In addition the black absorbs more radiation, while the white reflects.
So the white snowman kept the center of base glass cooler and thus increased the stress.
Bert Weiss
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Re: Whaddya think happened to this?

Post by Bert Weiss »

There is a list of problematic features here.
1. any sections of glass thinner than 6mm, when there are sections 6mm or thicker, attached.
2. white verses clear
3. white verses black
4. black verses clear

Heat from the elements is radiant heat. Radiant heat passes through clear glass to heat the shelf below first. The shelf then heats the glass, by conduction. On the other hand the heat hits the white glass and it absorbs some and reflects some. The black and colors absorb heat.
Bert

Bert Weiss Art Glass*
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Furniture Lighting Sculpture Tableware
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