jrgpots Posted August 31, 2016 Report Share Posted August 31, 2016 I found a very nice oil spot glaze posted on Facebook by Clara Giorello. She took a cone 10 oilspot glaze, "Daly's oilspot" and changed it to a cone 6 glaze by adding Ulexite. I had not even heard of Ulexite before, so a google search taught me that Ulexite is a sodium borate mineral. It is also known as Sodium Calcium pentaborate octahydrate. It sounds like very cool stuff. It forms complex crystals that refract the light. It is known as "TV Stone." It is similar to Colmenite without the Silica and alumina. Gersley borate has a small amount of it. Clara Giorello ground the mineral herself. Her recipe is: cone 6 K feldspar 40 quartz 30 Talc 10 Kaolin 10 Ca Carb 10 add: RIO 10 Ulexite 10. I tried to find a supplier for Ulexite. I found an import company that was willing to sell me a metric ton of the stuff. Has anyone ever used this and by chance found a distributor? Jed Link to comment Share on other sites More sharing options...
No Longer Member Posted August 31, 2016 Report Share Posted August 31, 2016 I love that; it looks like a glaze Monet would use. Link to comment Share on other sites More sharing options...
glazenerd Posted August 31, 2016 Report Share Posted August 31, 2016 Colemanite or Calcium Borate are probably the only two closely related that you will be able to find. Ulexite came from the old Death Vally (CA) mine where gerstley borate was mined: but closed a few years back. Nerd Link to comment Share on other sites More sharing options...
Min Posted August 31, 2016 Report Share Posted August 31, 2016 Hi Jed, You can order a sample from Plainsman Clay in Canada. Tony has a few glazes where he has experimented with it. link on this page: https://digitalfire.com/4sight/material/turkish_ulexite_1657.html Link to comment Share on other sites More sharing options...
Tim T Posted September 4, 2016 Report Share Posted September 4, 2016 Not wanting to be picky, but that isn't an oil spot glaze any more, even if attractive. Oil spot glazes are formed by the thermal decomposition of a saturated red iron oxide glaze, which only occurs at temperatures over about 1250C Link to comment Share on other sites More sharing options...
Wyndham Posted September 4, 2016 Report Share Posted September 4, 2016 it also looks like a reduction fired test, as iron does go green in reduction Link to comment Share on other sites More sharing options...
pautts Posted September 14, 2016 Report Share Posted September 14, 2016 That's really cool. Thanks for sharing Link to comment Share on other sites More sharing options...
pautts Posted September 14, 2016 Report Share Posted September 14, 2016 Not wanting to be picky, but that isn't an oil spot glaze any more, even if attractive. Oil spot glazes are formed by the thermal decomposition of a saturated red iron oxide glaze, which only occurs at temperatures over about 1250C Whether it is the reduction of iron or not, it looks like there is some gas being released to cause the effect. It seems close enough to me. Link to comment Share on other sites More sharing options...
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