Compatibility Question

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Michele-MD
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Compatibility Question

Post by Michele-MD »

First, this question has absolutely nothing to do with any price increase or availability of glasses.

I have a large quantity of Spectrum stained glass from "way back when" when I first started doing glass. I am doing open face castings with a bunch of kids and I wondered if this glass might work for them as long as I only use glass from the same sheet for one casting? I would like to use some nice streakies and if this would work it would be a win-win as I would not have to go buy other glass and I would use of glass that has been in my studio for over 10 years. The glass would be cut into pieces, stacked in the plaster molds, and then fused at around 1530 for 20 minutes. I figure the glass had to have been made hot and cooled so don't know why it should have a problem with essentially being "reheated" and cooled again, but I also don't want to risk messing up their projects. Anybody fused/casted with Spectrum Stained Glass? I can't think of a simple test that would provide the answer that does not use of the same glass I want to use. Thanks!
DonMcClennen
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Re: Compatibility Question

Post by DonMcClennen »

most glass taken from the same sheet will fuse together with good success.. having said that you will likely experience devit from Spectrum especially at the 1500F temp. If you Superspray before fusing this will eliminate that problem. Spectrum "96" was formulated to reduce devit. as well as being compatible. It is also possible that if your glass is all Spectrum then there is a good chance several sheets will fall within the same compatible range and can be fused together even though not marked! The same manufacturing process often prodices same C of E. You can of course test for this. Fire away and have fun!! [-o<
"The Glassman"
Brad Walker
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Re: Compatibility Question

Post by Brad Walker »

As far as compatibility goes, it should work fine so long as you only use glass from one sheet in one casting.

However, you may have trouble with some of the glass devitrifying during the firing. That may or may not be an issue for the pieces, but in the worst case I've had streakies devitrify so badly they actually fall apart after the firing. And some transparents may turn opaque during the firing.

I don't know of a way to test that isn't destructive, but you might want to fire some small pieces off the sheets just to see how they behave during a full firing before using them to do the casting.

I would anneal at 950F.
Kevin Midgley
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Re: Compatibility Question

Post by Kevin Midgley »

I would echo Brad's comment about crumbling stained glass after fusing it.
I have had that happen.
One absolutely beautiful piece of Merry Go Round glass could not even be picked up off the mold having turned itself into untouchably breakable frit.

I also have a piece of glass casting which was given to me by a local artist which has glass disease. The artist uses Spectrum glass pretty much exclusively but in the piece with the disease, some of it may not have been fusible.
It started by absorbing moisture from the air and became white and powdery and from there to falling apart in chunks. Quite beautiful to watch month by 6 months by years but certainly not what you want in art pieces. This all was not immediately evident with the piece when it was first finished. :shock: :shock: :shock:

Given that Spectrum is going out of business with glass that will never be made again, your glass you think has little value now, will be highly desirable to obtain in the future.

In my experience using non fusible glass for an art project is a complete waste of time.

Even if you do the flame test in a propane torch (and proceed at your own risk!!! ) of melting pieces of glass together and evenly pulling the stringer to test for compatibility, all bets are off for glass disease occurring at a later date. Straight stringer = even COE....maybe and curved stringer says unequal COE...maybe.

Spectrum was notoriously bad for fusing before the days of 96. I keep reject fused pieces of it on the wall of my studio to show people what happens when you don't use a good fusible glass like Bullseye for fusing. I add one day the pieces are going to fall off the wall by themselves once the cracks decide to grow some more.
Michele-MD
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Re: Compatibility Question

Post by Michele-MD »

Sigh, thanks for the education. Don't think this is such a good idea after all. Penny wise, pound foolish.....
Kevin Midgley
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Re: Compatibility Question

Post by Kevin Midgley »

If you want to experiment, the best chance you have is to use only cathedrals and only blues and greens from a single sheet. Once again that glass may increase in value over time and it would be a pity to waste it.
It comes down to the the fact that if you don't value your time and you test test test, you may come up with something ala Kay Kinney's Glass Craft 1962 book.

Simpler would be to clean bottles and fire them over the molds so they learn about molding glass and they each get a flattened molded by them bottle at the end of it.
Dani K
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Re: Compatibility Question

Post by Dani K »

first , I'm a bullseye guy, fusing 90 the last 30 years. but I'm also teaching fusing for kids in art camp that the price matter. so about ten years ago i assumed that spectrum glass is compatible 96 by definition and in the worse case i will have some devitrification issues. i did a few test bars on 96 clear from uroboros and choose about 15 colors randomly from spectrum non tested selection. placed two pieces from each color, one on the clear and one above , to check vitrification.all transparent colors came out with no different above or under that include water glass , opac colors are milky but compatible exept the white. never turned back and used hundred of sheets with happy faces , the kids don't even know. fired like any other 96 schedule. the last two years we using the scap from the same glass to prepare "blocks" that my son pull to rods they use for blowing or just back for fusing elements, full recycling.
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