Bill Kielb Posted April 9, 2021 Report Share Posted April 9, 2021 1 hour ago, liambesaw said: Yeah but if it says the ratio made the glazes durable with no leaching, but then a few paragraphs later talked about how they leached quite a lot. “The Background Poor durability of glazes can be attributed to a condition called ion exchange. In this process, hydrogen present in the acids in food and base in soaps can displace the alkali metal (lithium, sodium, potassium) in the glaze.ii This process can be restricted by having an ideal flux ratio of 0.3 R2O 0.7: RO via unity molecular formula in glazes at all temperatures, as defined by Katz.iii” have not seen any research to contradict this actually. I think it’s more useful than not really and the correlation is fairly strong. Restricted seems a good descriptor. Link to comment Share on other sites More sharing options...
liambesaw Posted April 9, 2021 Report Share Posted April 9, 2021 7 minutes ago, Bill Kielb said: “The Background Poor durability of glazes can be attributed to a condition called ion exchange. In this process, hydrogen present in the acids in food and base in soaps can displace the alkali metal (lithium, sodium, potassium) in the glaze.ii This process can be restricted by having an ideal flux ratio of 0.3 R2O 0.7: RO via unity molecular formula in glazes at all temperatures, as defined by Katz.iii” have not seen any research to contradict this actually. I think it’s more useful than not really and the correlation is fairly strong. Restricted seems a good descriptor. Oh sure, I agree with .3:.7, I'm just saying that paper made no sense, because even at .3:.7 there was significant leaching above 3% copper. I'd just say restricted compared to what? And how do they know? The evidence is missing from the paper. Link to comment Share on other sites More sharing options...
Bill Kielb Posted April 10, 2021 Report Share Posted April 10, 2021 49 minutes ago, liambesaw said: The evidence is missing from the paper. It was his 2012 research I believe which this paper was to examine leaching and actual toxicity. His gloss test were pretty consistent as I recall. Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted April 10, 2021 Report Share Posted April 10, 2021 It doesn’t help that UMF doesn’t look at colourants like copper or iron as fluxes, when they do behave that way. Link to comment Share on other sites More sharing options...
Bill Kielb Posted April 10, 2021 Report Share Posted April 10, 2021 53 minutes ago, Callie Beller Diesel said: It doesn’t help that UMF doesn’t look at colourants like copper or iron as fluxes, when they do behave that way. Extended UMF https://wiki.glazy.org/t/unity-molecular-formula-umf/826 Free spreadsheet calculator as well. How can you beat that! Link to comment Share on other sites More sharing options...
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