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meisie

Attaching With Slip

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I recently took a class where one of our assignments was to create a seed pod of some sort. The instructor showed us that in order to attach items to our pod we scored and slipped and all should be well. The piece came out of bisque just fine and then I glazed and was pretty sure the pieces I attached were firmly attached. Mostly because I remember trying to get the brush into the edges and I don't recall seeing that much of a gap. Since it's come out of the glaze firing the pieces that I had attached and glazed are pulled away from the base. My question is..... can that continue to happen after the piece has been bisqued? Is it a result of my not adding or scoring and slipping correctly? Attached is a photo but you can't see the area that's affected. It's the yellow vines that pulled away but fortunately not breaking off.

Thanks for the assistance.

Renee

post-2460-12969612870374_thumb.jpg

post-2460-12969612870374_thumb.jpg

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I recently took a class where one of our assignments was to create a seed pod of some sort. The instructor showed us that in order to attach items to our pod we scored and slipped and all should be well. The piece came out of bisque just fine and then I glazed and was pretty sure the pieces I attached were firmly attached. Mostly because I remember trying to get the brush into the edges and I don't recall seeing that much of a gap. Since it's come out of the glaze firing the pieces that I had attached and glazed are pulled away from the base. My question is..... can that continue to happen after the piece has been bisqued? Is it a result of my not adding or scoring and slipping correctly? Attached is a photo but you can't see the area that's affected. It's the yellow vines that pulled away but fortunately not breaking off.

Thanks for the assistance.

Renee

 

Renee Most of the time the cracks are very hard to see, pouring some water on that area might have revealed the cracks. Shrinkage between the body of the pot and the yellow vines was probably the problem. The body was probably dryer and firm for stability than the decorative vine clay pieces that still need to shrink to get to the same stage the body was in. If I feel that a piece I am working on needs a little extra help in balancing the moisture content between the body and the attachments, I will place a small section of moist T-shirt material in that area until it softens slightly before I continue with any attachments. I hope this helps! Denice (Wichita, KS)

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Higher firing temperatures will show flaws that sneak past bisque ... More heat = more shrinkage.

 

I agree with Denice on the likely cause.

The ideal would be to work with the whole vessel at the same stage of wetness but this is not always possible. Another solution is to cover the piece with plastic so the moisture evens out, then gradually loosen the plastic to allow more air in until you finally just leave it in open air. You'll have to gauge when to loosen by watching and feeling the pot. Don't rush the drying ... Depending on your clay body it could take days or even weeks. When you put that much work into a piece, it's worth waiting a bit.

 

.

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Higher firing temperatures will show flaws that sneak past bisque ... More heat = more shrinkage.

 

I agree with Denice on the likely cause.

The ideal would be to work with the whole vessel at the same stage of wetness but this is not always possible. Another solution is to cover the piece with plastic so the moisture evens out, then gradually loosen the plastic to allow more air in until you finally just leave it in open air. You'll have to gauge when to loosen by watching and feeling the pot. Don't rush the drying ... Depending on your clay body it could take days or even weeks. When you put that much work into a piece, it's worth waiting a bit.

 

.

 

 

Thank you both. I appreciate the answers. I ended up firing this particular piece at home because it didn't fit the parameters of the lesson. (I made a new one for the assignment instead). I'm still new to firing and I was not sure if things still moved or pulled away during a glaze firing. There was a tremendous amount of breakage from all sorts of pieces during this class and I wonder if it was because we were pressed for time. Assignments were due every two weeks which didn't allow for a lot of time in the build and then drying time. Thanks again.

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I recently took a class where one of our assignments was to create a seed pod of some sort. The instructor showed us that in order to attach items to our pod we scored and slipped and all should be well. The piece came out of bisque just fine and then I glazed and was pretty sure the pieces I attached were firmly attached. Mostly because I remember trying to get the brush into the edges and I don't recall seeing that much of a gap. Since it's come out of the glaze firing the pieces that I had attached and glazed are pulled away from the base. My question is..... can that continue to happen after the piece has been bisqued? Is it a result of my not adding or scoring and slipping correctly? Attached is a photo but you can't see the area that's affected. It's the yellow vines that pulled away but fortunately not breaking off.

Thanks for the assistance.

Renee

 

Renee Most of the time the cracks are very hard to see, pouring some water on that area might have revealed the cracks. Shrinkage between the body of the pot and the yellow vines was probably the problem. The body was probably dryer and firm for stability than the decorative vine clay pieces that still need to shrink to get to the same stage the body was in. If I feel that a piece I am working on needs a little extra help in balancing the moisture content between the body and the attachments, I will place a small section of moist T-shirt material in that area until it softens slightly before I continue with any attachments. I hope this helps! Denice (Wichita, KS)

 

 

Thank You. It does help and the t-shirt idea sounds like a good one. I did this in a class and most of the time we were in a hurry to get assignments done which may have been part of the issue.

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i agree with both Chris and Denise. I like to dry mine very slowly and if I notice parts drying earlier than others i wet them down again with spray bottle or other. be sure to use clay that shrinks at the same rate percentage wise for each section. You may need to do some shrink tests at bisqe and vitrification.

but drying should be done evenly or you will have trouble.

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