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Whispering Grass

Refiring

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Hello,

 

I have fired some bisqueware black pots with a glaze that hadn't really taken ... to the extent that I wan't to retry firing these pots, adding another glaze on top of the one that disappeared.

 

I am not sure whether I can refire items ? It is the interior of the bowl that I want to reglaze. The exterior of the bowl will be left unglazed.

 

thanks in advance.

 

Lorraine

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Hello,

 

I have fired some bisqueware black pots with a glaze that hadn't really taken ... to the extent that I wan't to retry firing these pots, adding another glaze on top of the one that disappeared.

 

I am not sure whether I can refire items ? It is the interior of the bowl that I want to reglaze. The exterior of the bowl will be left unglazed.

 

thanks in advance.

 

Lorraine

 

Lorraine since it's the inside of bowls that you want to reglaze you should be able to try it without worrying about a glaze mishap in your kiln. If your trying to save the bowls you need to test your new glaze over a test tile with the old glaze fired on it already. You might have had the original glaze to thin or mixed it wrong if you made it your self, you could try reglazing with the original glaze or making a new batch and see if it works any better. I would just have fun with it and try different glazes in the bowls, I don't consider myself a glaze guru somebody else may have a better idea. Denice (Wichita, KS)

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Hello,

 

I have fired some bisqueware black pots with a glaze that hadn't really taken ... to the extent that I wan't to retry firing these pots, adding another glaze on top of the one that disappeared.

 

I am not sure whether I can refire items ? It is the interior of the bowl that I want to reglaze. The exterior of the bowl will be left unglazed.

 

thanks in advance.

 

Lorraine

 

Lorraine since it's the inside of bowls that you want to reglaze you should be able to try it without worrying about a glaze mishap in your kiln. If your trying to save the bowls you need to test your new glaze over a test tile with the old glaze fired on it already. You might have had the original glaze to thin or mixed it wrong if you made it your self, you could try reglazing with the original glaze or making a new batch and see if it works any better. I would just have fun with it and try different glazes in the bowls, I don't consider myself a glaze guru somebody else may have a better idea. Denice (Wichita, KS)

 

 

 

 

- thanks Denice - will go play again :-)

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I have been re-glazing pieces for years sometimes to fix a pot often to enhance a pot. If I am re-glazing to repair a glaze fault I will take a small amount of glaze from the bottom of the bucket before I mix it and brush the thick glaze on to the spot/s that require attention then back into the kiln for a "normal" glaze firing. If I want to enhance the piece I mix the bucket of glaze take a small amount of the mixed glaze and add brush medium then brush the glaze over the existing glaze in what ever pattern. Then back in the kiln for a "normal" glaze firing. this has worked in both oxidation and reduction firing. Please note that firing pieces over and over can damage the work and cause it to crack. Some clays crack more then others. Heavy stoneware can take a lot, Porcelain not so much.

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These are great tips. I too have been disappointed when small areas have lost their glaze during firing...and have tried refiring. I think the key is to warm the pots first. I don't know if this is the right way to do it, but sometimes I put the piece in my regular oven for a a few minutes at about 200F , then apply some glaze and refire to the same cone as last time.

But here's something I don't understand:Someone at the pottery studio where I take a class had a glazing disaster. Our instructor suggested heating her piece with a heat gun, then reglazing it, which she did. But the pottery gods didn't like it -- and all the new glaze completely disappeared during the refiring. I don't quite get that. There was absolutely NO sign of the new glaze when the piece came out of the kiln. I might expect it to run, or puddle, or change color -- but completely disappear? Do any of you more experienced potters have any explanation for this?

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I have been re-glazing pieces for years sometimes to fix a pot often to enhance a pot. If I am re-glazing to repair a glaze fault I will take a small amount of glaze from the bottom of the bucket before I mix it and brush the thick glaze on to the spot/s that require attention then back into the kiln for a "normal" glaze firing. If I want to enhance the piece I mix the bucket of glaze take a small amount of the mixed glaze and add brush medium then brush the glaze over the existing glaze in what ever pattern. Then back in the kiln for a "normal" glaze firing. this has worked in both oxidation and reduction firing. Please note that firing pieces over and over can damage the work and cause it to crack. Some clays crack more then others. Heavy stoneware can take a lot, Porcelain not so much.

 

 

Tom.....Great tips on re-glazing, but what are you referring to when you said "and add brush medium"? Thanks.

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Brush Medium is a product I buy from Aardvark in Santa Ana in California, I think other companies carry it. You add it to your dip glaze to make it brushable. I don't know what it is made of, If I did I would make it myself and pass on the recipe. it doesn't last long in the glaze so I just use it when I need it and only in small amounts.

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When using a heat gun to heat a pot for re-glazing it may get the pot too hot and cause the new glaze application to form small cracks, before its fired. when the pot is fired the glaze can pull back from the crack. Cracks in the glaze coat is a common reason for crawling in glazing both on bisque ware and on re-glaze. The reason for the cracks are varied. Heating the pot is a good way to get the glaze to stick. But with all thing ceramic it takes practices, ya the hated "P" word

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I've got a weird happening, too. One of my students didn't like the way a teapot came out of the firing, and decided to refire with low fire glazes. First time through she used a commercial glaze "floating blue" (which fires a rich brown with blue flashings of color) and she was happy with that result.

 

However, the other trim glazes are the ones she refired. Imagine my surprise when opening the kiln--the lowfired glazes were bright and beautiful, the "floating blue" had turned a murky khaki color with veins of brown running through it. Original firing was cone 5, and refired at cone 06. What could cause this metamorphosis. Even took it to local supply shop and everyone was stumped.

 

I often refire to add more definition or just perk up color and this was truly a first. Any suggestions?

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I've got a weird happening, too. One of my students didn't like the way a teapot came out of the firing, and decided to refire with low fire glazes. First time through she used a commercial glaze "floating blue" (which fires a rich brown with blue flashings of color) and she was happy with that result.

 

However, the other trim glazes are the ones she refired. Imagine my surprise when opening the kiln--the lowfired glazes were bright and beautiful, the "floating blue" had turned a murky khaki color with veins of brown running through it. Original firing was cone 5, and refired at cone 06. What could cause this metamorphosis. Even took it to local supply shop and everyone was stumped.

 

I often refire to add more definition or just perk up color and this was truly a first. Any suggestions?

 

 

Wow. I can't help with your question, but am really interested in the refiring with low fire glaze to perk. Any problems with clay/glaze fit when you do this? I understand the object is already vitrified when it goes back in for it's lowfire glazing...just wondering if you've ever noticed any crazing, or any other issue on the glaze fit with the second firing. I'm definitely going to try this -- as I often have glazes slipping of the body etc...and would love to add some low fire color in a second firing. Never heard of anyone doing this before (but then, I haven't heard of much!) Thanks for sharing.

Leslie

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