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Soda Ash Wash And Electric Firing


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#21 Magnolia Mud Research

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Posted 13 March 2017 - 12:05 AM

I soaked a porcelain lidded jar (about three inch diam by three inches tall) in a liter container of soda ash solution until all the liquid evaporated. The jar was covered with white crystals. Dried over summer break. Fired in reduction gas kiln to cone 10 sitting on sea shells . Lid was glazed to bottom, thick clear glaze all over. Some crazing of glaze as expected. No carbon trapping. Looked good. Otherwise a boring pot with stuck lid.

For three years I routinely fired all my work with a sprayed coats of one or more of borax, trisodiumphosphate, or soda ash saturated solutions either before,after, or without a dipped coat of one of our studio cone 10 glazes. No disasters. On raw clay the effects were similar to wood firing in color. On porcelain reddish color with a sheen from TSP.

LT

#22 Babs

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Posted 13 March 2017 - 12:16 AM

I have asked this question before, and it is only because it is a similar colour which appears on the pots to soda wash, but no sheen...

I've been getting a toasty colour on some of my bisque ware. When tumbled packed the toasty colour can be seen on the parts of the pots with more surface to the atmosphere of the kiln, esp pots at the top of the kiln. toploader.

This is only occurring since I purchased a new kiln .

I had a glaze run onto the kiln floor and a shelf, it contained magnesium, glaze puddle still there, well evidence of it, I didn't feel like digging into my new floor.

AND I have done the soda ash wash on pots.

Any of these actions cause a colouring of my white bisque ware? No photos of this but will look out for it.

I bisque terracotta and the white clay pots in same firing but I have done this for ever.

This kiln is unvented, I leave the bungs out till 700deg.C

It's a piglet of a kiln. with all bungs open, 25 deg. /hr to 100degC and 100/hr to 600, then 150 to end, it still oozes rust coloured stuff onto my verandah floor. verandah is covered , sides as well where the kiln sits.

My ware is dried , well same as for ever, but I am just a couple of Kms. from the ocean.

Any suggestions welcome.



#23 Joseph F

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Posted 13 March 2017 - 06:13 AM

Eh, it doesn't sound like it is worth the results when glazing over it. I will give it a few shots to see but thanks for all the information everyone.



#24 Babs

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Posted 13 March 2017 - 08:25 PM

Joseph, I applied it to the bottom 1/3 of my pot, and glazed to that point. I was careful not to handle the area of soda wash incase I removed some with my fingertips.

I saw no ugly over fluxed areas, the interface of soda and glaze seemed ok, you could put a resist over the soda wash perhaps

I'll try to find a photo.



#25 Joseph F

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Posted 13 March 2017 - 08:27 PM

It's okay babs. Don't worry about it. I have been thinking about what I want and soda sheen isn't it. I appreciate the effort though.



#26 Babs

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Posted 13 March 2017 - 09:28 PM

wondering now whatthe soda ash soln. sprayed on top of glaze would do?/



#27 JBaymore

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Posted 14 March 2017 - 09:03 AM

wondering now whatthe soda ash soln. sprayed on top of glaze would do?/

 

Try it.

 

best,

 

................john


John Baymore
Adjunct Professor of Ceramics; New Hampshire Insitute of Art

Former Guest Professor, Wuxi Institute of Arts and Science, Yixing, China

Former President and Past President; Potters Council
 

http://www.JohnBaymore.com

http://www.nhia.edu/...ty/john-baymore


#28 glazenerd

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Posted 14 March 2017 - 09:21 AM

Do not apply it to the whole piece: glaze it and then do test spots with increasing amounts of ash. Then you have one piece you can judge effects on, in lieu of a side by side. Draw quadrant lines on the foot: and number 1-4 so you can track which quarter has what %.

 

Nerd



#29 Magnolia Mud Research

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Posted 14 March 2017 - 10:52 AM

I spray nearly saturated soda ash (SA)water over glazes at cone 10.  Be careful that you don't wash the glaze off when spraying. (I use a spray bottle with either a wide pattern, or a straight stream).  Never had a problem.  Sometimes the result was not as appealing as I expected.   I don't often use a 'runny' glaze, so have no data on SA over a 'runny' glaze.

 

like John said,  just try it and see what happens.

 

LT



#30 Joseph F

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Posted 14 March 2017 - 01:40 PM

I am going to be running test on these plates I am making seems like a good place to test the solution, I will post findings although at this point I don't expect a lot from it going over glazes.




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