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COE Adjustable Low Fire Clear Glaze
Auto Unity Formula
*Update Jan 2023:
G1916M 3124:3134:Kaolin:Silica Adjustable Clear on mug
Buffstone with G1916M at cone 03 (1950F) - crazing
G1916M applied very thick on new mix L215
No crazing after months. Fired 04. Milky because of thickness.
Alternate Code Number:GS04-1
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="COE Adjustable Low Fire Clear Glaze" id="63907" key="cs6EdQB9" date="2023-03-23" typecodes="ST" codenum="G1916M" picturebasename=""> <recipelines> <recipeline material="FERRO FRIT 3124" amount="38.000" tolerance=""/> <recipeline material="FERRO FRIT 3134" amount="38.000" tolerance=""/> <recipeline material="EPK" amount="20.000" tolerance=""/> <recipeline material="Silica" amount="4.000" tolerance=""/> </recipelines> </recipe> </recipes>
Cone 05+ Expansion Adjustable Gloss Base
*Although similar to the previous G1916M, this recipe provides greater thermal expansion adjustability. It combines a middle-of-the-road thermal expansion frit with a very low and very high expansion frit (they cancel each other out but increase gloss of the otherwise silky Frit 3195). The frits in this recipe are common (the 3249 less so but it deserves to be common because of its utility). We adjusted this in a later version, G1916QL1, it employs a kaolin for better clarity and more frit 3249 for glaze fit on more bodies.
G1916Q at Cone 01 on 3D+iron
Very nice results on L3724E red body at cone 01. Piece is very strong.
1916J and Q fired to 1450F
These glazes are starting to melt, the surface having reached the consistency of a porcelain and have densitfied to very low porosity. Notice the iron in the ball clay really shows up at this stage (it will be less evident later).
G1916Q Cone 04 using 04DSSC schedule
G1916Q and J fired 1650-2000F
Ten-gram balls melted and flattened as they fired. They soften over a wide range, starting well below cone 010! At 1650F carbon material is still visible (even though the glaze has lost 2% of its weight to this point), it is likely the source of the micro-bubbles that completely opacify the matrix even at 1950F (cone 04). This is an 85% fritted glaze, yet it still has carbon; think of what a raw glaze might have! Of course, this is a thick layer, so the bubbles are expected. But they still can be an issue on a piece of ware. So to get the most transparent possible result it is wise to fire tests to find the point where the glaze starts to soften (1450F in this case), then soak the kiln just below that (on the way up) to fire away as much of the carbon as possible.
Success with cyrstal clear glaze cone 03
Uses Cone 03 soak-soak-slow cool schedule.
G1916Q on L215, L212, L210, L213, Buffstone at cone 03
All exited from the klin without crazing. The L215, L213, L210 and L212 samples subsequently survived a 300F/Icewater test without crazing, but the Buffstone did not. The L213 would not likely survive a cold-to-hot test without shivering.
1916Q cone 04, 03
G1916Q on L210 fired at cone 04
Has survived for a year without crazing.
G1916Q+2%Iron on L212 talc body fired at cone 05
This will likely shiver over time. But the speckle that happens on white bodies is clearly visible.
G1916Q applied thickly on L215 fired cone 04
No crazing after 2 months.
G1916Q on L4170 cone 04
Thin application is clearly the way to get the best transparent. The glaze eventually craze where application is thicker.
XML (to paste into Insight)
<?xml version="1.0"?> <recipes version="1.0" encoding="UTF-8"> <recipe name="Cone 05+ Expansion Adjustable Gloss Base" id="56565" key="irHk7RR9" date="2023-10-31" codenum="G1916Q"> <recipelines> <recipeline material="Ferro Frit 3195" amount="65.000" tolerance=""/> <recipeline material="Ferro Frit 3110" amount="10.000" tolerance=""/> <recipeline material="Ferro Frit 3249" amount="10.000" tolerance=""/> <recipeline material="No. 5 Ball Clay" amount="15.000" tolerance=""/> </recipelines> </recipe> </recipes>