ayresrock Posted July 18, 2012 Report Share Posted July 18, 2012 I live in england and have an electric kiln so dont use cones - when i read about cone 6 - is this for orton small cones or ?? your articles on electric kilns are very good but will be better when I can know what temps to use - thanks Link to comment Share on other sites More sharing options...
neilestrick Posted July 18, 2012 Report Share Posted July 18, 2012 Kilns can be fired to any cone by either using the small cones or bars in the sitter, or by using large witness cones on the shelf. Either way is fine. If you have a digital kiln, you don't need to use any cones at all unless you think it's not firing accurately, in which case you should set some large cones in the kiln to see exactly how the kiln is firing. Cones are the most accurate method of measuring heat work. There has been a lot of discussion here lately about people's sitters and controllers not being accurate to the witness cones they place on the shelf. Personally (I'm going to be the bad guy here), putting witness cones on the shelf and checking them during every firing is a waste of time if you have a sitter or digital controller. The entire purpose of the sitter or controller is to do away with watching cones bend. If you need to use large witness cones occasionally for calibration purposes, fine. But to use them every time is unnecessary in my opinion. Link to comment Share on other sites More sharing options...
Christine Posted July 18, 2012 Report Share Posted July 18, 2012 I live in england and have an electric kiln so dont use cones - when i read about cone 6 - is this for orton small cones or ?? your articles on electric kilns are very good but will be better when I can know what temps to use - thanks Have a look a this http://www.porcelainpainters.com/conechrt.htm .... there are other charts out there on the internet too Hope this helps Christine Link to comment Share on other sites More sharing options...
ayresrock Posted July 18, 2012 Author Report Share Posted July 18, 2012 Kilns can be fired to any cone by either using the small cones or bars in the sitter, or by using large witness cones on the shelf. Either way is fine. If you have a digital kiln, you don't need to use any cones at all unless you think it's not firing accurately, in which case you should set some large cones in the kiln to see exactly how the kiln is firing. Cones are the most accurate method of measuring heat work. There has been a lot of discussion here lately about people's sitters and controllers not being accurate to the witness cones they place on the shelf. Personally (I'm going to be the bad guy here), putting witness cones on the shelf and checking them during every firing is a waste of time if you have a sitter or digital controller. The entire purpose of the sitter or controller is to do away with watching cones bend. If you need to use large witness cones occasionally for calibration purposes, fine. But to use them every time is unnecessary in my opinion. Link to comment Share on other sites More sharing options...
ayresrock Posted July 18, 2012 Author Report Share Posted July 18, 2012 Thanks - what i need to know is what temp cone 6 is - as there are different makes of cones and their temps are different - so when I read that i should use cone 6 what type of cone are you using? Orton? and a small or large one - or some other and what equivalent temp would i set my kiln to? be grateful for answer - hope this is clear - I dont have a spy hole so cant check during firing there is agood article on firing http://ceramicartsdaily.org/category/firing-techniques/electric-kiln-firing/ which refers to cone 6 all the time but not to the temp - Link to comment Share on other sites More sharing options...
LawPots Posted July 18, 2012 Report Share Posted July 18, 2012 There are different kinds of cones (besides Orton), but most North Americans are referring to large Orton cones. In Mastering Cone 6 glazes, by Hesselberth and Roy, "Cone 6" appears to be 15 minutes at 1200 C. I note this is part of a more elaborate firing schedule that includes controlled cooling and a slow ramp speed to the top temperature, and the reader is warned that the temperature setting is dependent on the equipment's calibration and age. The problem with just using temperature is that kilns can achieve the melting temperature of glazes, and then fail to fully melt some glaze recipes because the kiln achieved the temperature too fast, shut off, and cooled too quickly. In more than one book (and my kiln manual) the recommendation is that the kiln sitter prevents accidents and overfiring, it doesn't replace reading cones. So far this recommendation matches my limited experience with my Cress Firemate that has a kiln sittter. I should think that with the increased use of computer controlled electric kilns, while cones aren't necessary, many potters will continue to talk in cones because cones measure melt, which is a function of temperature and time - not solely temperature. Link to comment Share on other sites More sharing options...
DAY Posted July 19, 2012 Report Share Posted July 19, 2012 I live in england and have an electric kiln so dont use cones - when i read about cone 6 - is this for orton small cones or ?? your articles on electric kilns are very good but will be better when I can know what temps to use - thanks Use your google; in this case "Orton Cone Chart", and all your questions will be answered. Link to comment Share on other sites More sharing options...
ayresrock Posted July 19, 2012 Author Report Share Posted July 19, 2012 thanks - to everyone - as we have a number of different cones here - many thanks Link to comment Share on other sites More sharing options...
yedrow Posted July 19, 2012 Report Share Posted July 19, 2012 I fire with large free standing cones (guard, witness, and guide 7,6,5). In every firing the kiln sitter has went off well before the witness cones. I've been told (meaning hearsay) that kiln sitters vary wildly in their shut off points when using the small triangular (tetrahedral) cones at ^6. I've also been told that you can get much better results if you use bar cones instead. But I've yet to do so. Perhaps I need to see if I can calibrate my kiln sitter. I had assumed it would have come calibrated new. I'm pretty new to kiln sitters I'm afraid, and for most of my potting time have used kiln controllers. I see some figerin' out time ahead. I guess you calibrate a soak period at the end of the firing into the sitter? Link to comment Share on other sites More sharing options...
Dinah Posted July 24, 2012 Report Share Posted July 24, 2012 Why not call up someone at Potterycrafts, Ltd. Or Staunton (sp) Kilns. Link to comment Share on other sites More sharing options...
Arnold Howard Posted July 25, 2012 Report Share Posted July 25, 2012 Perhaps I need to see if I can calibrate my kiln sitter. I had assumed it would have come calibrated new. I'm pretty new to kiln sitters I'm afraid, and for most of my potting time have used kiln controllers. I see some figerin' out time ahead. I guess you calibrate a soak period at the end of the firing into the sitter? You should check the Kiln Sitter calibration after every 12 firings. You will need a firing gauge, which is a metal disk that is included with new kilns. A standard Kiln Sitter does not have a soak feature. However, after the Kiln Sitter trips, you can add a manual soak. Sincerely, Arnold Howard Paragon Industries, L.P., Mesquite, Texas USA ahoward@paragonweb.com / www.paragonweb.com Link to comment Share on other sites More sharing options...
yedrow Posted July 26, 2012 Report Share Posted July 26, 2012 Thanks Arnold, I didn't know that. I'm sure I once had that calibration device but I didn't know what it was, lol. I've been told so many bad things about kiln sitters that I pretty much just just use them as a safety device. Perhaps I need to take another look at them. Until about two months ago I didn't even know you could calibrate them. I've always just used large cones. Link to comment Share on other sites More sharing options...
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