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glazing and firing greenware


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#1 anniec9

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Posted 26 November 2012 - 07:28 PM

I'm a newbie, Christmas is fast approaching and I need to bisque and glaze some pots I need in a hurry. How can I glaze greenware and cut out the bisque firing?

#2 Lucille Oka

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Posted 26 November 2012 - 09:00 PM

Once firing is possible, however I recommend brushing the glaze on to the ware. If you dip the ware into the glaze, too much glaze and too much water may be absorbed which can cause the fragile greenware to fall apart and maybe even into the glaze vat. Fire the ware very slowly with a preheat just as you would a regular bisque firing but fire the ware to the maturing temperature of the glaze. Be sure to keep the feet clean of glaze and wipe off any excess with a damp sponge.
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#3 Marcia Selsor

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Posted 27 November 2012 - 07:31 AM

If you dip greenware is should be leather hard and not dry. This prevents too much absorption as mentioned by Lucille. Also a glaze recipe used on bisque ware needs to have bentonite added to use on greenware. 5% is the normal amount to add.
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#4 anniec9

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Posted 27 November 2012 - 04:04 PM

Once firing is possible, however I recommend brushing the glaze on to the ware. If you dip the ware into the glaze, too much glaze and too much water may be absorbed which can cause the fragile greenware to fall apart and maybe even into the glaze vat. Fire the ware very slowly with a preheat just as you would a regular bisque firing but fire the ware to the maturing temperature of the glaze. Be sure to keep the feet clean of glaze and wipe off any excess with a damp sponge.



#5 anniec9

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Posted 27 November 2012 - 04:10 PM

Thanks Marcia and Lucille for your replies. As you have probably guessed it's a last minute rush to get everything fired for sales and gifts. Thanks again.

#6 neilestrick

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Posted 27 November 2012 - 04:49 PM

I would test everything first!
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#7 oldlady

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Posted 27 November 2012 - 10:11 PM

it might be time to check out spraying your glazes. i single fire after spraying glaze. very little gets wetter than will dry within a few minutes in a warm space.

it may be heresy but my last kiln load had never fired pieces and previously fired but too thin a coating of glaze items on the same shelf. it all came out fine. have been doing this for years without problems. it takes experience to get just the right amount of glaze on a piece when using a sprayer so sometimes i do have to fire something twice. not often, though.
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#8 anniec9

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Posted 27 November 2012 - 10:37 PM

it might be time to check out spraying your glazes. i single fire after spraying glaze. very little gets wetter than will dry within a few minutes in a warm space.

it may be heresy but my last kiln load had never fired pieces and previously fired but too thin a coating of glaze items on the same shelf. it all came out fine. have been doing this for years without problems. it takes experience to get just the right amount of glaze on a piece when using a sprayer so sometimes i do have to fire something twice. not often, though.





What temperature (cone ) did you fire this last load to? And I'm using a gas kiln, would it make a difference?

#9 Avaviel

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Posted 28 November 2012 - 12:34 AM

[...] And I'm using a gas kiln, would it make a difference?



I talked to my professor about this very topic tonight! He suggested that if you fire with a gas kiln, to whatever cone (6 to whatever) that you 'candle' the kiln overnight. You turn on the pilot light, and then that will dry out the work if it isn't dry already. Also, you can dip your work, just use care and don't use tongs. Those were his words, but they do make sense.

#10 anniec9

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Posted 28 November 2012 - 05:41 AM


[...] And I'm using a gas kiln, would it make a difference?



I talked to my professor about this very topic tonight! He suggested that if you fire with a gas kiln, to whatever cone (6 to whatever) that you 'candle' the kiln overnight. You turn on the pilot light, and then that will dry out the work if it isn't dry already. Also, you can dip your work, just use care and don't use tongs. Those were his words, but they do make sense.




Thanks for talking to your professor, I am basically a self taught potter with the help of lots of books, DVD's, friends who are potters also, and forums like this. I wish
I had taken a TAFE or Uni course when I was younger, but at my stage of life, I feel it's too late. As a general procedure I do "candle" the kiln with the small burner to dry out the pots for a bisque fire, so will continue with this when glazing and firing greenware. Thanks again.

#11 oldlady

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Posted 28 November 2012 - 06:39 PM


it might be time to check out spraying your glazes. i single fire after spraying glaze. very little gets wetter than will dry within a few minutes in a warm space.

it may be heresy but my last kiln load had never fired pieces and previously fired but too thin a coating of glaze items on the same shelf. it all came out fine. have been doing this for years without problems. it takes experience to get just the right amount of glaze on a piece when using a sprayer so sometimes i do have to fire something twice. not often, though.





What temperature (cone ) did you fire this last load to? And I'm using a gas kiln, would it make a difference?




i fire to cone 6 exclusively. i have no experience firing a gas kiln.
"putting you down does not raise me up."

#12 Avaviel

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Posted 28 November 2012 - 08:28 PM

Thanks for talking to your professor, I am basically a self taught potter with the help of lots of books, DVD's, friends who are potters also, and forums like this. I wish
I had taken a TAFE or Uni course when I was younger, but at my stage of life, I feel it's too late. As a general procedure I do "candle" the kiln with the small burner to dry out the pots for a bisque fire, so will continue with this when glazing and firing greenware. Thanks again.


Don't worry about taking a class as much! That is, unless you have time. You can learn just as much outside of a class by reading books and such. The point of school isn't a piece of paper saying you graduated, but the people you meet who have the same goals. (Don't mention that to certain professors and administrators, they believe that paper is the only goal one should have in life!)

Historically, Lucie Rie was a potter who fired glazed greenware. In her studio, she kept a pilot light lit at all times. This would dry out the work in her studio. (You could maybe invest in a dehumidifier, if safety is an issue. Or, you could chance an uncontrolled studio-kiln fire!) She sometimes brushed on the glaze... while spinning it on a wheel!

I'd wonder if it would be best to bush on glaze when the work isn't bone dry, and then let it dry. This way, you could apply the glaze while it already has a little moisture still making the piece strong. But that's just my personal wonderings.

Really, you just need to use care that you don't break the greenwear while you glaze it. Personally, I see myself brushing the outside of bowls after pouring glaze on the inside.

#13 anniec9

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Posted 30 November 2012 - 12:13 AM

Thanks everyone for your words of wisdom and help. Will take it all on board and try it out. Thanks again.

#14 Marcia Selsor

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Posted 30 November 2012 - 02:40 PM


Thanks for talking to your professor, I am basically a self taught potter with the help of lots of books, DVD's, friends who are potters also, and forums like this. I wish
I had taken a TAFE or Uni course when I was younger, but at my stage of life, I feel it's too late. As a general procedure I do "candle" the kiln with the small burner to dry out the pots for a bisque fire, so will continue with this when glazing and firing greenware. Thanks again.


Don't worry about taking a class as much! That is, unless you have time. You can learn just as much outside of a class by reading books and such. The point of school isn't a piece of paper saying you graduated, but the people you meet who have the same goals. (Don't mention that to certain professors and administrators, they believe that paper is the only goal one should have in life!)

Historically, Lucie Rie was a potter who fired glazed greenware. In her studio, she kept a pilot light lit at all times. This would dry out the work in her studio. (You could maybe invest in a dehumidifier, if safety is an issue. Or, you could chance an uncontrolled studio-kiln fire!) She sometimes brushed on the glaze... while spinning it on a wheel!

I'd wonder if it would be best to bush on glaze when the work isn't bone dry, and then let it dry. This way, you could apply the glaze while it already has a little moisture still making the piece strong. But that's just my personal wonderings.

Really, you just need to use care that you don't break the greenwear while you glaze it. Personally, I see myself brushing the outside of bowls after pouring glaze on the inside.


If the work is bone dry the glaze can get sucked in too quickly for a thick application. You can also get cracking.
Marcia




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