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AndreaB

Terra Sig

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Morning all,

 

Can you help please.  I'm doing a raku workshop this weekend and I need to produce some pots using terra sig.  I use a commercial raku clay and I need to know if I can use it slaked down to produce the terra sig?

 

Marcia's video indicates ball clay, but I'm confused as to whether I should use stoneware ball clay?

 

Thanks for your help

 

Andrea

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I am not sure what stoneware ball clay is. Stoneware clay is stoneware clay like Goldart and is used in stoneware clay body recipes.

Ball clay is added to stoneware clay recipes for plasticity. 

 

What is the "stoneware ball clay" label?  

 

For terra sig you want a fine particle clay . Letting the clay settle, could give you a smooth terra sig if the particles are fine enough. I can only say try it. I would recommend ball clay if you want a white surface which is what I use on porcelain. Sumi's article is right on. 

Many clays will work for terra sig.

Marcia

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I have used the slaked down slip from various commercial clay bodies to make TS.  I just dilute the slip, shake it up vigorously and then let it settle a few minutes, and decant the fluid from the heavies that sink. Discard the heavies, and repeat the process several times to get the really big particles out.  I then let the fluid settle for several hours or overnight, before pouring off the fluid to use as TS.

This is also the method I have used to make TS from local clay collected from pot holes and such. 

This has worked OK for me.

 

LT

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(originally in the duplicate thread, removed so it can be deleted)

 

Yes, you can. At the end of the day, terra sigillata is just fine particles of clay.

 

This is a good article:

http://ceramicartsdaily.org/pottery-making-techniques/ceramic-decorating-techniques/terra-sigillata-101-how-to-make-apply-and-troubleshoot-terra-sig/

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Thanks for the info. I went and got some ball clay, somehow I've messed up Marcia's recipe and the mixture won't split (over 24 hrs). So I'm going to try this. It's an excerpt from a thread 4 yrs ago:

 

"1 kilo of ball clay in a 5 liter plastic water bottle jug. fill it with clean water add .25% of sodium silicate and .25% of soda ash. That is 2.5grams of each product. make sure it is all mixed up smooth. After 20 hours, poke a hole 1/3 the way up from the bottom and let the top 2/3 of the thin liquid run into a bowl. It will be very watery. discard the bottom 1/3. Be careful during the entire time to not disturb the sediments as they will ruin your terra sig".

 

I'm using the terra sig for a raku workshop so this recipe will make more than I need.  How can I use the left overs? I fire in an electric kiln and at present don't have the option for firing raku in it.

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Andrea, how did the Terra sig work out? For electric firing, if you want to leave the exterior bare, and maybe decorate with slips or underglazes, terra sig can be a nice base. But it will not be of any use if you are going to cover it in a glaze.

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I have used Redart, Goldart, and ball clay to make sigs.  I have used Vince Pitelka's method of making it and it has worked great for me.  I am sorry I don't know how to post a link, but you can search his name and I am sure you will find the help you need.

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Andrea, how did the Terra sig work out? For electric firing, if you want to leave the exterior bare, and maybe decorate with slips or underglazes, terra sig can be a nice base. But it will not be of any use if you are going to cover it in a glaze.

Douglas, I'm not certain how it turned out!.  The piece looked great after the naked raku process.

 

post-65376-0-74280100-1477539815_thumb.jpg

 

I have a lot of terra sig left over so I'll use on other pieces.

 

:)

post-65376-0-74280100-1477539815_thumb.jpg

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Thanks for the info. I went and got some ball clay, somehow I've messed up Marcia's recipe and the mixture won't split (over 24 hrs). So I'm going to try this. It's an excerpt from a thread 4 yrs ago:

 

"1 kilo of ball clay in a 5 liter plastic water bottle jug. fill it with clean water add .25% of sodium silicate and .25% of soda ash. That is 2.5grams of each product. make sure it is all mixed up smooth. After 20 hours, poke a hole 1/3 the way up from the bottom and let the top 2/3 of the thin liquid run into a bowl. It will be very watery. discard the bottom 1/3. Be careful during the entire time to not disturb the sediments as they will ruin your terra

 sig".

 

 

 

Are you saying the TS didn't visibly separate? How much darvon did you use? left over TS can be kept for years. If it dries up add some water.Why is the surface on the naked clay pied so like orange peel? You can sand it with a diamond pad. That is what David Roberts does. His work feels like a glaze.

 

Marcia

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