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Old 06-06-2018, 03:03 PM
Dan Vanantwerp
Posts: n/a
Hi Dave, Always glad when you have a chance to chime in.

I made sure my sample was struck prior to pulling threads, but it would be tough to try and get it matched to the level of strike for a piece completely worked and boxed.

Have you read the opal phos technical posting put out by Gaffer on their website? They suggest that the bubbles of PO4 continue to grow as the piece is worked making compatibility a bit of a moving target.

In the archives, on a different discussion about compatibility, there was mention of someone working on a piece for 5 hours. Imagine the change in expansion for an opal phos by the time it was boxed if it even made it! Someone else said that opal phos reacts violently with water which I hope you would agree is not true. Pete was a bit skeptical and asked what the chemistry behind that was. I can't imagine what was happening. That you were pre-wetting your batch suggests you took it with a grain of salt.

It's like a course in recent (and sometimes not-so-recent) glass history in that section. There is mention of a cad-sel red opal phos. Did that ever get made?

You're probably right about the iron in the Cristalica, but I plead ignorance of the source. That crucible (80lb) has been kept isolated from anything but cullet. Nice to have a redox indicator built into the glass.

I am on the same wavelength as you with merging Brossphate with Chalcedony. I think Pete has mentioned a phosphate based chalcedony as well. I'm taking my steps to get there and learning along the way. One great thing I take with me as a recipient of an advanced degree...I know how to learn, how to be taught and how to teach myself.
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