Aditi Posted February 16, 2019 Report Share Posted February 16, 2019 I'm planning to use amaco cone 05 glaze in a semi automatic kiln. How long & at what temperature should I soak the glaze till it matures? Should I get a programmable kiln or will a semiautomatic do? Link to comment Share on other sites More sharing options...
hitchmss Posted February 16, 2019 Report Share Posted February 16, 2019 If you have the budget for a computer controlled kiln ( a kiln with a controller) vs a manual kiln I highly recommend it. Amaco may recommend a soak at ^05 on the bottle, or on their website; check with them to see if they recommend a soak and if so for how long. A soak at temp will do a number of things(heal over any pin holes/blisters, etc) for the glaze, but once it reaches 05, the glaze will be mature. Soaking it too long will keep the glaze at maturation for too long, and could lead to it running off the shelf. You wont be able to "tell" by looking through the peep hole if the glaze has matured to your like at 05; will need to turn off and wait until cool to inspect results. If amaco doesnt recommend a length for soak, I would start at 10 minute increments and see what that does for your results; a one hour soak at a temp is equivalent to firing one cone higher than your target temp (i.e. a one hour soak at 05, makes it an 04 firing). The temperature is the cone; fire to cone 05 for a cone 05 glaze, cone 5 for a cone 5 glaze, and so on. Google for a pyrometric cone chart; will tell you specific temps for each cone. Link to comment Share on other sites More sharing options...
Bill Kielb Posted February 17, 2019 Report Share Posted February 17, 2019 @hitchmss Not sure about lowfire temperatures but when I fire the test kiln (or our other kilns for that matter) to cone five with a 20 minute hold I generally get a perfect cone 6 bend. I have always heard + 15 to + 25 minutes is generally the next cone up so one hour might prove to be a bit long. Link to comment Share on other sites More sharing options...
hitchmss Posted February 17, 2019 Report Share Posted February 17, 2019 @Bill Kielb I had always been told 1 hour=1 cone up, but I dont soak any of my kilns, except for a 10 minute for bisque at 06, so I cant say that Ive experienced this first hand. Link to comment Share on other sites More sharing options...
neilestrick Posted February 17, 2019 Report Share Posted February 17, 2019 The hold time per cone calculation is not consistent. I've tested cone 6 with a hold to get to 8, and it took 40 minutes. Cone 4 with a hold to 6 took over an hour. Generally, 20 minutes per cone is a good starting point, though. I also found that some glazes do not respond to long holds the same as if they were fired hotter. Sometimes you need heat, not just heat work. Link to comment Share on other sites More sharing options...
Min Posted February 17, 2019 Report Share Posted February 17, 2019 From Orton: "Hold time also affects the bending or deformation of Pyrometric cones. Generally, firing to an equivalent temperature for a cone and then soaking for about 1-2 hours will be sufficient heat work to deform the next higher cone number. Additional soaking of 4-6 hours will deform the following cone, and some 16-20 additional hours will be required to deform the next higher cone in the series." Excerpt from this page, under the section Effect of Heating Rate, Hold Time and Kiln Atmosphere. Link to comment Share on other sites More sharing options...
Bill Kielb Posted February 17, 2019 Report Share Posted February 17, 2019 @neilestrick Yes that would be absolutely consistent with the differential between cone temperatures. Seger created cones that represented silica, and alumina in a flux of 0.3:0.7. The temperature between cones varies considerably whereas the additional energy over time holding at a particular temperature is more uniform so 20 minutes is a decent approximation in typical firing temperatures. An hour is probably too long. I also agree holding at the top often does not enhance or cure glazes that have problems. Link to comment Share on other sites More sharing options...
Bill Kielb Posted February 17, 2019 Report Share Posted February 17, 2019 4 minutes ago, Min said: From Orton: "Hold time also affects the bending or deformation of Pyrometric cones. Generally, firing to an equivalent temperature for a cone and then soaking for about 1-2 hours will be sufficient heat work to deform the next higher cone number. Additional soaking of 4-6 hours will deform the following cone, and some 16-20 additional hours will be required to deform the next higher cone in the series." Excerpt from this page, under the section Effect of Heating Rate, Hold Time and Kiln Atmosphere. Definitely interesting and definitely not my experience for sure. Good thing Seger invented those things and Orton sold them here in the states. Link to comment Share on other sites More sharing options...
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