Cone 6 Oxidation Results Group 5
Thus far I have batched over 120+ different glazes in 300 gram batches, the formulas for which have been found from publicly available sources. After firing these tests in an electric kiln to Cone 6, I have photographed each and am making them available to potters with the accompanying formulas.
One difference with this Group 5 is that I have introduced a cooling cycle to the firing. The cycle is as follows and the firing is accompanied by a Cone 6 witness cone. After 12 consecutive firings, the witness cones are identical from firing to firing.
The firing cycle:
| Rate | Temp | Hold Time | ||
| rA1= 360 | F1 = 900 | 0 | ||
| rA2= 300 | F2 = 1800 | 0 | ||
| rA3 =200 | F3 = 2016 | 0 | ||
| rA4 = 108 | F4 = 2197 | 0.3 | ||
| rA5 = Full | F5 =1800 | 0 | ||
| rA6 =150 | F6 = 1300 | 0 | ||
| rA7 = 0000 |
To summarize, I fire at a rate of 360/hr to 900 degrees F, then at 300 degrees/ hr to 1800 degrees F, 200 degrees/hr until 2016 degrees F is reached, then 108 degrees/hour to 2197 at which time I hold it at that temperature for 30 minutes.
The kiln is shut off until a temperature of 1800 degrees F is reached and then turned on to slow the rate of cooling to 150 degrees/hr until 1300 degrees F is reached. At this point the kiln is turned off and cools naturally.
I use a Vulcan kiln controller attached to a Paragon QA11 test kiln. The combination of new elements in the Paragon and new thermocouple and controller has produced consistent heat work from one firing to the next.
Links to Cone 6 Groups 1 - 4 without controlled cooling.
Group 1
Group 2
Group 3
Group 4
Group 5 results with controlled cooling.
1C (C denotes controlled cooling)
#1 Jen's Juicy Fruit Variation (Red Matte) C/6
EPK 10%
Gillespie borate 9%
Nepheline syenite 49%
Flint 12%
Whiting 11%
Lithium carbonate 9%
Soda ash 10%
Titanium dioxide 5%
Red iron oxide 10%
2C
#2 - Jen's Juicy Fruit Variation 2 (Red Matte) C/6
EPK 10%
Gillespie borate 9%
Nepheline syenite 49%
Flint 12%
Whiting 11%
Lithium carbonate 9%
Standard Ceramic's #487 Red Stain 10%
Soda ash 10%
Titanium dioxide 5%
#2 normal cooling same formula
3C
3 - Pete's Tomato Red #3 C/6
Kona F-4 (Minspar) 33.7%
Frit 3134 9.8%
Bone ash 10.7%
Whiting 3.8%
Magnesium carb 5.9%
EPK 12.5%
Flint 23.7%
Bentonite 2%
Red iron oxide 8%
4C
4 - Tomato Red #13 C/6
Frit 3134 10.8%
Nepheline syenite 23.1%
Bone ash 10%
Magnesium carb 6.2%
Whiting 7.7%
EPK 21%
Flint 21.2%
Bentonite 2%
Red Iron Oxide 10%
#4 without cooling cycle.
5C with cooling cycle
5 - Tomato Red #13 Pumpkin Orange C/6
Frit 3134 10.8%
Nepheline syenite 23.1%
Bone ash 10%
Magnesium carb 6.2%
Whiting 7.7%
EPK 21%
Flint 21.2%
Bentonite 2%
Red Iron Oxide 10%
Rutile 2%
#5 without cooling cycle.
6C with cooling cycle.
6 - Tomato Red #13 with spodumene C/6
Frit 3134 11%
Spodumene 11.2%
Bone ash 7.9%
Magnesium carb 6.3%
Whiting 7.9%
EPK 21.6%
Flint 21.7%
Neph Syenite 11,8%
Bentonite 2%
Red Iron Oxide 10%
6 - without cooling cycle.
8C - with cooling cycle.
8 - Jen's Juicy Fruit Variation (Red Matte) Cone 6
EPK 10%
Gillespie borate 9%
Nepheline syenite 49%
Flint 12%
Whiting 11%
Lithium carbonate 9%
Soda ash 10%
Titanium dioxide 5%
Black Iron Oxide 6%
8 - without cooling cycle.
12C - with cooling cycle.
12 - Jen's Juicy Fruit Variation Whiting C/6
EPK 9%
Gillespie borate 10%
Nepheline syenite 50%
Flint 7%
Wollastonite 15%
Lithium carbonate 9%
Soda ash 10%
Titanium dioxide 5%
Black iron oxide 6%
12 - without cooling cycle.
18C - with cooling cycle.
18 - Jade Green C 5/6
G200 38.1%
Barium Carbonate 19%
EPK 9.6%
Flint 9.5%
Gillespie Borate 9.5%
Zinc Oxide 9.4%
Copper Carbonate 4.9%
18 - without cooling cycle.
Great experiments. I have tested many of these glazes with a different schedule. Basically a similar heating cycle but the cooling was done dthe following way: fast to 1800 then up to 2000 at 50/hr.
ReplyDeleteI have results posted on http://vvargespottery.typepad.com/vvarges_pottery/2011/01/old-iron-red-photos.html
Also look for results on Coleman teadust with same schedule. Send me an email if you want further details.
Interesting! thanks for sharing these!
ReplyDeleteYou should give John Post credit for his recipes on this page. I have been to his site and it looks like you have benefited greatly from his recipes.
ReplyDeleteI have not visited John's page but if he is the source of some of these recipes then he is due credit for them. Thank you, John Post, if you derived some of these glazes.
ReplyDeleteThank you for sharing your recipes. I'm a high school senior and we're doing research on different glaze variations for Cone 6. I need all the help that I can get because we are doing our own Cone 6 high fire glaze. I'm just hoping that my experiment comes out just as good as these. The glazes are beautiful and I look forward to trying some of these recipes out.
ReplyDeleteJaynie, remember glazing to get the effect you want means not only the formula, but the application (thickness, ect), the clay underneath, the firing schedule and other factors. Make lots of pieces so you get lots of practice so you can learn to control the process. Best of experiences to you. Terry
ReplyDeleteTerry, do you think that various slips (particularly white) would show through many of these glazes? Im particularly curious about the Tomato red, Waterfall Brown 72, 122 Transparent - T12 C/6 Reddish Brown, and 145 - Satin Matt Cone 6 Lt. Green.
ReplyDeleteAlso, thank you so much for the effort and time youve dedicated into making these test tiles. They are wonderful!
Looks like most all these glazes run. If fired to true cone 6, probably need to add some kaolin or alumina.
ReplyDeleteMost of the runs come from double dipping the tiles. So you are correct to suggest stiffening with kaolin or alumina. However, with single dip, there was no running with most of these glazes,
ReplyDeleteI recently spoke to Pete Pinnell about this very glaze (the glaze is usually referred to as Pete's Tomato Red #13, after him). Pete is the professor at University of Nebraska at Lincoln. I thought I'd share his comments on this particular glaze:
ReplyDeleteThis glaze performs best at a true cone 6 or a hot cone 6. The key to developing good color is to hold at one temperature on the cool down (in the range of 1800° to 1600°F) for 1 to 3 hours to allow the crystals to develop. The hotter the hold temp, the more deep burgundy red. The cooler the temp, the closer to orange red color. Do not confuse this with a slow cool down. Pick a temp, cool normally until you hit that temp, and then stay there for 1 to 3 hours, after which you'd resume cooling down at a normal rate.
Thanks, Anne. As you might note above, I have done a slower cooling rate down from 1800 to 1300 @150/hour. I will try the hold technique and report back when I have some results.
ReplyDeleteHola por favor me podrías traducir: Gillespie Borate, Wollastonita, Flint,
ReplyDeleteNepheline sienita, muchas gracias.