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Old 08-12-2017, 05:24 PM
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Pete VanderLaan Pete VanderLaan is offline
The Old Gaffer
Join Date: Apr 2002
Location: Chocorua New Hampshire
Posts: 22,178
Pete VanderLaan is on a distinguished road
Normally, the colorants are simply not going to affect the expansion if they stay in ranges that hover around .10% as a max. There are indeed colors that can exceed that and it's a rare bird where you don't have to compensate with some alkaline flux but that won't usually exceed .10 percent either with a few notable exceptions. Go above 1% and you can see problems. You have to test. If Corning actually had legit co-efficients which were not the W&S numbers, I'd surprised and then pleased. I mentioned the lithium since it was such a significant difference. You really have to consider what it is you're trying to do. Making colored glass is one thing, making color rods is quite another. You can wind up making stuff that is only kinda sorta glass. The enamels can fall below 50 percent silica.

I get a fair idea about the general interest in this by looking in on the board dedicated to color. It's really marginal.
Where are we going and why am I in this basket?
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