Share form Insight-live.com (Lab Documentation and Calculation System) by Digitalfire
See Also: G3806C Cone 6 Panama Fluid Melt Clear Glaze Development
Panama Cone 6 Transparent Glaze
High fluid melt glaze for reactive effects and super gloss colors
This recipe was the product of a series of tests to determine the best direction for a brilliant fluid-melt transparent base glaze for copper blues and greens. Once I selected a specific recipe (Panama Blue), I removed the colorants and made adjustments to improve its slurry properties and lower the thermal expansion to stop crazing. This type of base glaze is needed because more stable transparents lose their gloss on brown bodies and when certain colorants are added. Fluid melt base glazes also produce much more interesting visual effects. But of course, they have a down sides: they can run off the ware onto the shelf if too thick! And they have an inherently higher thermal expansion so crazing is more of an issue (but it is not impossible to solve as you will see here).
Copper Blue G8306C using copper carbonate, oxide
Right is G3806C, an adjustment to drop the thermal expansion of B. It does this by trading some of the high-expansion KNaO for a mix of MgO, ZnO and SrO. These is an improvement but it still could craze over time on high-kaolin or low silica porcelains.
Plainsman P300, M370 with copper blue glaze cone 6
This is the G3906C base plus 2.5% tin oxide and 2% copper oxide. The green glaze does craze over time on these bodies, but the inside glaze is a liner than will not.
3806C vs. other cone 6 clear glazes on a dark stoneware
Each pair of mugs shows a numbered glaze vs. G3806C on the right. The body is a red burning cone 6 stoneware, Plainsman M390.
G2926B, 3806C vs. Amaco C11 Clear at cone 6
Bottom right is P300 with three coats of C11.
G3806C Copper Blue on Polar Ice
Polar Ice is the easiest of Plainsman middle fire porcelains to fit a glaze to, although this glaze crazes on most other porcelains, it should stay craze free on this.
G3806C on a dark burning cone 6 stoneware
Plainsman M390. There is still some clouding, but it is better than other transparents we have used.
1 - Midnight
Fire fast to 2100F (300-400F/hr), then 100F/hr to 2200F, then drop fast to 2000F and soak half hour, then cool at 100F/hr to 1400F.
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Panama Cone 6 Transparent Glaze" keywords="High fluid melt glaze for reactive effects and super gloss colors" id="75786" key="haH5px2r" date="2017-10-23" codenum="G3806C" email="email@example.com"> <recipelines> <recipeline material="Silica" amount="26.300"/> <recipeline material="Kaolin" amount="19.700"/> <recipeline material="Dolomite" amount="8.700"/> <recipeline material="Strontium Carbonate" amount="4.400"/> <recipeline material="Ferro Frit 3110" amount="31.100"/> <recipeline material="Ferro Frit 3134" amount="6.600"/> <recipeline material="Zinc Oxide" amount="3.300"/> </recipelines> </recipe> </recipes>
M370 Transparent Liner Base
Perkins Fritted Clear Plus Silica
Auto Unity Formula
This is the standard cone 6 whiteware clear base glaze made by Plainsman Clays. Mix it at the proper specific gravity and gel it correctly to get a very workable slurry. Visit the page at plainsmanclays.com for pictures and more information on mixing and using it (look for the word whiteware and the code G2926B). The page for this glaze at the Digitalfire Reference Database also has lots of pictures and notes (see link below).
F1 - +Alumina
Adding as a fining agent to get crystal clear over underglaze decoration.
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="M370 Transparent Liner Base" keywords="Perkins Fritted Clear Plus Silica" id="56342" key="m5RnxyDp" date="2018-05-12" codenum="G2926B"> <recipelines> <recipeline material="Nepheline Syenite" amount="18.300"/> <recipeline material="Ferro Frit 3134" amount="25.400"/> <recipeline material="EPK" amount="19.600"/> <recipeline material="Wollastonite" amount="6.900"/> <recipeline material="Silica" amount="37.600"/> <recipeline material="Silverline Talc" lookup="Talc" amount="2.300"/> </recipelines> </recipe> </recipes>