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Old 03-30-2005, 01:04 PM
Lani McGregor
Posts: n/a
Originally posted by Tom Littleton

I can't remember when I started putting a measured COE in the sales material. I think fairly recently and likely when everyone else started talking about COEs and stuff and started to look at the 87 as a standard. No more than 8-10 years at the most but I'd have to check and I didn't always keep good records of when I made changes. It seems like it became more of an issue when the Dichroics came out and people wanted to use them in their furnace worked glass and the 90 standard stuff would not work with the SP 87. And likely after Pete learned how to build and operate a a dilatometer.
Tom, thanks. This is the input I was looking for. COE as a measure of compatibility seems to have showed up in the vocabulary of studio glass very recently (certainly quite a while after BE published Glass Fusing Book One in 1983 and our side of the market – i.e. kilnworkers - grabbed the “shorthand” tag of “90 fits 90” with all its half-accuracies and commercial agenda).

I'm not saying that the batch or color manufacturers are wrong to provide COE info, just that users think this equates to compatibility when any colored glass maker knows it doesn't.

Tom, do you provide an Annealing Point for SP 87? (Not the annealing range – the AP as determined by the ASTM test)? A softening point?
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