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Old 03-29-2005, 02:00 PM
Lani McGregor
Posts: n/a
Originally posted by Pete VanderLaan
The early Kugler had NO references to expansion factors. It just magically fit.
Magic? During the time when Hopper visited the Eisch factory in 1969 (per David this AM) they were testing for compatibility two ways:

- the thread pull test (which, as we all know, measures the differences between glasses based on the combined factors of their viscosity and their expansion)

- a softening point test (which, not to insult anyone’s intelligence here, is also an indicator of viscosity).

I’d assume that Kugler - located so close to Eisch - if he was testing for compatibility at all, was using similar methods. But that’s an assumption. Maybe he was using magic. As you state, it appears that he was NOT using LEC.


Expansion really entered the mainstream as something to measure after Paul's article.
Again, I’d love to find this article. Got a date/issue number?


But Lani, why the interest outside of the fact that you guys have a proprietary interest and don't really think L.E.C. is all that critical compared to viscosity- which may be because you tend to work with big long flat sheets that can really drag themselves around a lot.
I’m not sure what you mean by “proprietary interest”. Can you explain?

And I’m also not real clear on what “big long flat sheets” have to do with it.

As to our not thinking LEC is critical, that’s NOT what Dan’s been saying. His sole argument is that it’s only half the story and has oddly become a standard with the inherent problems of all over-simplifications.

Why the interest?

A) material science/history curiosity

B) having to deal with the confusion/suspicion that continually results (what you call “eyes glazing over”) in trying to insert viscosity into the compatibility discussion.

C) marital discord: the other day as Dan was banging his head yet again against the kitchen wall trying to clarify LEC/viscosity relationships to my dull (and hugely unscientific) brain, I shrieked back at him in my best Fishwife voice “Aren’t you going to feel like an asshole if it turns out that this problem of equating the COE with compatibility really got going when you and that lame-ass ex-partner of yours wrote that stupid book in ’83 and suddenly [at least in our corner of the market] it was all “COE 90 glass and COE 86 glass” blah blah blah. Now that I’m hearing it’s all Paul Manners’ fault, I just need to find Mrs Manners and see whether LEC screwed up her marriage too.

So, where’s this article?
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