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Old 08-18-2019, 03:48 PM
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Quote:
Originally Posted by Bradley Howes View Post
Im going to take a stab at this sulphur blue either tonight or tomorrow, depends on what time I finish my drive back to Alfred. My big question is how much sulphur should I use? I’m thinking between 1-5% which is probably over kill but I have no idea. I’m planning on mortaring the sulphur with some boric acid. The sulphur we have is as chips but clumps together unbelievably in the mortar. From there, I’ll mix it into the rest of the boric acid and charge it. Any thoughts?
****
Thats an awful lot of sulfur. Stick to 1% and see what you get besides a potentially ruined crucible. You might consider covering the pot.
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Old 08-18-2019, 07:09 PM
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Thanks for the heads up on the calcium.
Regarding Moles, Ive read a chapter in a chemistry book about moles and will have to read it a dozen more times to see how I could actually use the information. I kind of get the idea but not so much that I can make use of it yet. Ill study it more.
I agree that the presence of so much alkali could present a problem. This is probably the first hurdle: how to sufficiently acidify the glass.
regarding the elemental sulfur I thought it was yellow also but according to Weyl:"Polysulfides as a rule are stable only in alkaline media and decompose fairly rapidly when the medium is acidified. If acid is poured into a polysulfide solution the decomposition leads to hydrogen sulfide and elementary sulfur. the latter aggregates, leading to colloidal and macroscopic particles. The same phenomenon can be observed in glasses if a polysulfide containing melt is mixed with a strongly acidic oxide, such as B2O3 or P2O5." and later "This blue color, being due to elementary sulfur, cannot be obtained in glasses which contain major amounts of zinc, cadmium or other ions of heavy metals with an affinity for sulfur." He does not explain how much the medium needs to be acidified or if the polysulfides form again if re-exposed to an alkali media.
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Old 08-18-2019, 07:25 PM
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well, start with the lack of commercial applications. True of silver glasses amongst others.

you are in an uphill battle which I doubt will end well.
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Old 08-18-2019, 11:53 PM
Paul Stout Paul Stout is offline
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I hear you, I see this as an experiment that will facilitate my learning rather than necessarily developing anything of consequence. Being new to the chemical approach towards glass Iím content with failed experiments if they help me better understand WTF is happening. I realize Iím pretty fortunate to be in a position to be able to say that. I love the suggestion of experimenting with different fluxes and stabilizers and I intend to pursue that also. With regards to commercial application for silver it seems Satava found a pretty good application with his jellyís. And donít most, if not all, luster glasses contain silver? Or perhaps youíre referring to colored rods whose primary colorant is silver?
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Old 08-19-2019, 09:09 AM
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keep in mind that sulfur is really toxic. The fumes tend to shut your airway down and you choke to death. I would encourage you to start small and see what happens. Too much won't really teach you anything. If you've ever been near a volcano, think brimstone, think sulfur. It won't go away easily either. I can't say what it will do to the pot

Ricks silver veil work was not uncommon in the seventies. Nick Labino was doing a lot of it, Bob Stephan did as well. I liked Paul Manner's veils the best. There were others. It's certainly not hard, not toxic and really, not expensive. Rick has not changed his work in forever. I don't know where he sells but he certainly seems to do well.

Real luster glasses have a lot of lead in them along with silver. Most rod glasses follow that formulation. Plating out silver requires some nitrates which I think supresses the strand tendency in that type glass and accomodates surface reduction.
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Old 08-21-2019, 04:20 PM
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So I read both Weyl and Volf on sulfur today and the blue tone is reduced to one sentence in the sulfur section of Volf. The conditions for making an acidic glass are formidable and will best happen in a phosphate which is acidic but it looks to be one of those longshots to me. I mean there are discussion of making rubies with cobalt but not in my shop.

What did impress me was looking at Strontium. Neither gives it much time when discussing phosphates and I'm not at all clear how Dave Bross came to the conclusions he did regarding replacing the calcium with Strontium, but he did it. Way to go Dave. That was good work.
At one point I suggested it to Croucher but he indicated that no one within 10,000 miles of him used it and cost would be prohibitive. Now John L is in Oakland even though John C has retired and working in his son's shop but John indicated to me recently that they had found the opalescense far denser with strontium as opposed to calcium so, again, great work.

What also strikes me in both books is that they really have the same problems that we have with a number of colorants. Silver is given a wide birth if you look to the calcedonias. Weyl does better with copper rubies than Volf does, both dance around phosphates. Many of the arguments then remain the arguments today. I remember once when John C and I were sitting around at Corning blathering with each other and John in passing said " Well I guess we proved that you certainly can melt lead crystal in an open hearth."

He was right. They used to say it couldn't be done. Had to be closed pots. Both of us think the phosphates are the last great mysteries in melts. The current boro work is really exciting and breaks so many barriers on melting cullet for color. If any of you go on with this, changing out the stabilizers is going to find you in a gold mine. I hope to spend more time on this as I find more free time from product.
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