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These two glazes have the same chemistry but different recipes. They are ultraclear and glossy and work best at cone 04-02.
Zero3 Ulexite Transparent Glaze For use with the Zero3 body and engobe
Total:100.00 Auto Unity Formula
Notes *This recipe converts the popular Worthington Clear Gerstley-Borate-based recipe into something much easier to use. While Worthington melts to a good clear it has serious gelling problems (characteristic of Gerstley Borate). Normal frits cannot easily source this high level of B2O3 so I have employed Ulexite to augment (a mineral similar to GB yet gels only slightly). Another issue with Worthington is shivering and fracturing of ware when glazed only on the inside (its thermal expansion was too low). This recipe also raises thermal expansion (by adding Na2O), the result is a glaze that fits a much wider range of bodies. Worthington also has clouding issues, this yields a more crystal clear, defect free fired result. Pictures Terrastone, L215 ![]() The successful firing of these mugs represents two years of testing to learn how to get a crystal clear glaze and how to create slips that dry and fire bond well! The firing schedule is very important: Cone 03 soak-rise-soak-slowcool. Slips are bright colored (they contain only 10% stains). Left: L3786E Plainsman Terrastone test mix with L3724M vitreous red slip with G2931F glaze. Wax resist exposes portions of the red slip which flashes near the glaze boundary. Center: Terrastone with L3685U vitreous white slip inside and brushed on (and 10% stained versions of it brushed on) with G2931F glaze. Right: L3724M vitreous red body with L3685U engobe (and stained versions of it) with G2931F glaze. Shivers on L212 ![]() L213 with G2931F glaze cone 04, 03, 02 ![]() Boiling water, ice water tested. None crazed. The cone 03 one was still good after a year. Zero3 body with G2931F Zero3 glaze ![]() The F version of the glaze employs Ulexite to source the boron (instead of frits). These Zero3 stoneware mugs were fired to cone 03 with underglazes. The right mug has the Zero3 engobe inside (under the glaze). G2931F (left), G2931G (right) on buffstone ![]() Cone 03. Did boiling water, ice water test on both. F crazes (notice the piece is waterlogged). G does not. Buffstone has a high porosity at this temperature so glazes must fit well. G2931F on F100, Buffstone, L212 and L215 ![]() Out of the kiln all fit. However it crazed on buffstone after boiling water, ice water test (use 2931G instead). The others are good. L212 crazes at cone 04. Firing temperature is important for Zero3 glaze ![]() This is G2931F on Plainsman Buffstone, L213, F100, L215. First column is cone 04, center is cone 03, right is cone 02. All exited the kiln without crazing except Buffstone at cone 04. We subjected all of them to a 300F:IceWater thermal shock. Buffstone crazed on all of them. L215 and L212 Cone 04 crazed. L213 was good but later the glaze was found to be under excessive compression, subject to shivering over underglazes. At cone 02 there are some dimples and defects. G2931F vs G2931K - Melted balls at cone 03 ![]() F, the Ulexite version, is obviously bubbling more, the percolation is causing the melt to spread out more on the tile. On the flow test is was less fluid. G2931F vs. G2931K on Polar Ice Low Fire ![]() 2931F was the Ulexite flused version of this recipe. The F survived three boil:ice cycles and 1 300F:ice cycle without crazing or shivering. The K is slightly smoother, tiny dimples in the surface are fewer. It is also applied thicker. G2931F vs 2931K flow test ![]() G2931F on Zero3 Porcelain ![]() The mug was decorated with underglazes at the leather hard stage, then bisque fired to 1650F, then dip-glazed and fired using a cone 03 drop-and-hold firing schedule. This glaze is exceptionally brilliant and clear, it transmits the color of the underglazes better than any other glaze at any other temperature I have seen. This glaze was later upgraded to one having the same chemistry but a higher frit content and firing even better, G2931K. G2931F on L212, L213 - After one year ![]() No crazing. Even after two years. A dazzling ultra gloss transparent glaze! Testdata LDW - LOI/Density/Water Content
XML (to paste into Insight) <?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Zero3 Ulexite Transparent Glaze" keywords="For use with the Zero3 body and engobe" id="75426" key="34roAJpc" date="2019-08-19" codenum="G2931F" picturebasename=""> <recipelines> <recipeline material="EPK" amount="27.000" tolerance=""/> <recipeline material="Silica" amount="7.000" tolerance=""/> <recipeline material="Ulexite" amount="29.000" tolerance=""/> <recipeline material="Ferro Frit 3249" amount="9.000" tolerance=""/> <recipeline material="Wollastonite" amount="9.000" tolerance=""/> <recipeline material="Ferro Frit 3110" amount="19.000" tolerance=""/> </recipelines> </recipe> </recipes> Born: 2014-03-19, Modified: 2019-08-19 10:47:48 |
Zero3 K Cone 03 Transparent Glaze
Total:95,000.00 (R) Auto Unity Formula
Notes *This recipe improves the popular Worthington Gerstley-Borate-based low fire clear recipe. It targets cone 03 to work best on Zero3 stoneware and porcelain. However many low fire bodies are dramatically stronger when fired to cone 03 with this (or one of its thermal expansion variants L & H). And the vast majority of commercial glaze products will fire easily to this temperature. If you absolutely must fire lower, to cone 06 or 04, then use the G1216Q recipe instead. Batch Ticket Notes These notes were entered in the notes panel under "Batch Ticket Notes" URLs How to tune the thixotropy of a glaze How to convert a d..o a brushing glaze Pictures G2931K on Zero3 Stoneware ![]() Fired cone 03. Body is Zero3 stoneware. Surface is perfect, even where thick. Ultra clear. Survived three boil:ice cycles and one 300F:ice cycle without crazing. G2931F vs. G2931K on Polar Ice Low Fire ![]() 2931F was the Ulexite flused version of this recipe. The F survived three boil:ice cycles and 1 300F:ice cycle without crazing or shivering. The K is slightly smoother, tiny dimples in the surface are fewer. It is also applied thicker. G2931F vs G2931K fritted - terra cotta mugs cone 03 ![]() F was the Ulexite-fluxed version of this recipe. G2931F vs G2931K flow test ![]() These two recipes have the same chemistry, but K sources boron from frits rather than Ulexite. Notice how much less bubbles there are in the flow and how much more predictable the melting pattern is. G2931F vs G2931K - Melted balls at cone 03 ![]() F, the Ulexite version, is obviously bubbling more, the percolation is causing the melt to spread out more on the tile. On the flow test is was less fluid. Firing temperature is important for Zero3 glaze ![]() This is G2931F on Plainsman Buffstone, L213, F100, L215. First column is cone 04, center is cone 03, right is cone 02. All exited the kiln without crazing except Buffstone at cone 04. We subjected all of them to a 300F:IceWater thermal shock. Buffstone crazed on all of them. L215 and L212 Cone 04 crazed. L213 was good but later the glaze was found to be under excessive compression, subject to shivering over underglazes. At cone 02 there are some dimples and defects. Three low fire bodies that need three clear glazes ![]() Because of glaze fit. Left: Plainsman Buffstone, contains no talc, fires buff. Center: L212 (about 25% talc). Right: L213 (about 45% talc, fires whiter). Talc raises thermal expansion. The centre glaze is G2931K (Insight-live reports COE 7.4), it fits L215 (also Zero3 porcelain and stoneware). It crazes on Buffstone and shivers on L213 and L212. G2931L has lower expansion (to work on zero-talc porous bodies). G2931H is higher (for talc bodies like L213). G2931K glaze precipitates things on storage ![]() G2931K On L212 after a year ![]() Some crazing starting. K on L215 at cone 04 ![]() The thicker version is clouding. The thinner one has micro-pinholes. It needs a higher temperature. G2931K o L215 - Cone 03, thick application ![]() G2931K on L215 - Cone 03 fired in 30 minutes ![]() Very transparent. No crazingafter many months. G2931K on L215 - Cone 06 ![]() Milky (because cone 06 is underfired for this glaze). But only a little crazing after a year. G2931K running on Zero3 Casting ![]() This happened at cone 03 and 04. The G3879 (left) did not run. For some reason G2931K easy applies to thickly on this body. This 1000 gram batch of glaze powde ![]() This 1000 gram batch of glaze powder screened 80 mesh immediately after making, and allowed to sit for 3 months prior to usage. The material in photo was screened out once again after the 3 month time lapse, (80 mesh once again). The largest balls are approx. 2.5 mm. in diameter, and when these particles were screened out, and still perhaps slightly wet?, they were quite easy to break in half with your fingernail. Typecodes ST-Untitled typecode Alternate Code Number:GS04-1 XML (to paste into Insight) <?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Zero3 K Cone 03 Transparent Glaze" id="95671" key="KyXwYm2r" date="2020-12-02" typecodes="ST" codenum="G2931K" picturebasename=""> <recipelines> <recipeline material="Ferro Frit 3195" amount="25.000" tolerance="" unitabbr="KG"/> <recipeline material="Ferro Frit 3134" amount="33.000" tolerance="" unitabbr="KG"/> <recipeline material="EPK" amount="20.000" tolerance="" unitabbr="KG"/> <recipeline material="Ferro Frit 3249" amount="10.000" unitabbr="KG"/> <recipeline material="Ferro Frit 3110" amount="7.000" unitabbr="KG"/> </recipelines> </recipe> </recipes> Born: 2006-03-16, Modified: 2020-12-02 07:32:09 |
Firing Schedule Name Cone 03 hold-rise-drop-hold Degrees (Fahrenheit or Celcius) F Schedule Type Rate Start Time and Temperature 8:01 am at 80F Program
Notes Used to glaze fire Zero3 porcelain and stoneware. However, there is a caution about bisquing these frit-containing bodies: They will vitrify in a typical firing, you must reduce the temperature to around 1500F (if ware is not absorbent enough fire lower). Note: this schedule is for the glaze firing, the previous two sentences simply referenced what is needed for the bisque. |