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a couple of questions on my first re-fire


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#1 Jime

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Posted 20 April 2013 - 05:40 PM

Hi all
last night was my first ever glaze firing, and I came in a little under temp.
Tonight I'm going to give it another shot and I have a couple of questions.

How fast can I ramp up the temperature? do I just start it on high, or go through medium and low first?
I'm going to switch out the witness cone for a new one, should I also change out the kiln-sitter cone?

Since this was my first glaze firing, I had a LOT of glaze tests in there. do you think that re-firing is going to give me a good idea of what the glazes will look like in the future, or should I assume that the tests won't be a good representation?

some technical details: I'm using commercial clay and glazes, using an electric Cress 23 kiln (small studio size). I bisqued to 04, and I was trying to fire to cone 6. my witness cone began to bend, but is still mostly straight, so I estimate that it got to cone 5.

last night's firing was 2 hours on low, 2.5 on medium, and it took 5 hours on HIGH to get to cone 5 (total firing was 10 hours). That seems long to me, I would have expected it to reach temperature a bit faster. does that sound normal to you?
thanks for all your help, this is pretty exciting!!

#2 gypsy

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Posted 20 April 2013 - 06:14 PM

Hi all
last night was my first ever glaze firing, and I came in a little under temp.
Tonight I'm going to give it another shot and I have a couple of questions.

How fast can I ramp up the temperature? do I just start it on high, or go through medium and low first?
I'm going to switch out the witness cone for a new one, should I also change out the kiln-sitter cone?

Since this was my first glaze firing, I had a LOT of glaze tests in there. do you think that re-firing is going to give me a good idea of what the glazes will look like in the future, or should I assume that the tests won't be a good representation?

some technical details: I'm using commercial clay and glazes, using an electric Cress 23 kiln (small studio size). I bisqued to 04, and I was trying to fire to cone 6. my witness cone began to bend, but is still mostly straight, so I estimate that it got to cone 5.

last night's firing was 2 hours on low, 2.5 on medium, and it took 5 hours to get to cone 5. That seems long to me, I would have expected it to reach temperature a bit faster. does that sound normal to you?






thanks for all your help, this is pretty exciting!!


It is exciting isn't it? I used to candle then go to medium then high. Now I candle and go straight to high...it works for me.. Good luck on your refire.



#3 Chris Campbell

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Posted 20 April 2013 - 10:22 PM

You are correct. Your results will not be 100% representative of what a single firing would be ... but they might be close enough / might not.

My Cone 5-6 firings take about 6 - 8 hours so that seems OK. Good Luck!

Chris Campbell
Contemporary Fine Colored Porcelain
www.ccpottery.com

TRY ...   FAIL ...  LEARN ...  REPEAT


#4 Marcia Selsor

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Posted 20 April 2013 - 10:53 PM

my ^6 firing are like Chris's... 6 to 8 hours. If your are refining porcelain I would not start on high. 'D be worried about shocking the dense body.
marcia

#5 Jime

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Posted 20 April 2013 - 11:12 PM

thanks for the help!
I've got it up and running. New cone and bar, and crossing my fingers for great success. I set it for a "fast firing", and I'm keeping notes on how the dial is moving. It did about 1 hour on low, and 1 hour on medium, just now getting to high... hope it's not too fast!

#6 High Bridge Pottery

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Posted 21 April 2013 - 06:58 AM

I do not know much about firing as I have only done it 10ish times. My firing schedule that got the best results was, 1 hour to 300 centigrade then full whack all the way to 1240 centigrade with a 20 min hold. I have no idea if this is the best but it has given me the best results. Maybe I should take it slower to start. Not sure on the time that it takes from 300 to 1240 but probably 4-6 hours.

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