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Cure for Greyed-out areas in pit-fired burnished ware


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#1 Isculpt

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Posted 07 November 2012 - 01:50 PM

On occasion, when I pit-fire burnished pottery (made from locally dug brownish colored clay), I'll get areas that are very light, dry-looking, and grey on the pots, as if that area got too hot in the fire. (That's just a guess; is that the correct diagnosis?) The grey area is not a fatal flaw, but it does detract from the rich warmth of the piece. I usually finish these pieces with a light coat of watered-down wax resist. Any suggestions for a colorant to add to the wax to dye that area? Or an alternative to wax?

#2 Marcia Selsor

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Posted 07 November 2012 - 03:09 PM

The gray may be a hotter spot, but also could be air hitting that spot. Do you smother the pit with saw dust and dried cow manure. Do you cover with sheet metal to prevent drafts?
That is what Maria martinez did for her black pieces.

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#3 Isculpt

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Posted 08 November 2012 - 01:04 AM

The gray may be a hotter spot, but also could be air hitting that spot. Do you smother the pit with saw dust and dried cow manure. Do you cover with sheet metal to prevent drafts?
That is what Maria martinez did for her black pieces.

Marcia


Marcia, I use the method of my Native American husband's tribe's 4,000+ year pottery tradition: After pre-warming the pots, I place them in the hot embers of a fire which has burned down, then I build another fire over the pots and after it burns down, smother it with pine bark. I'm not trying for solid blacks, but rather for the mottled browns and greys and blacks...which are, in my experience, harder to acquire than the solid blacks of San Ildefonso pottery. Muddy browns are the sometimes deeply disappointing results in addition to the grey hot spots. But oh, what a joy when it works well and I get the deep black spots on the brown pottery -- !

#4 Marcia Selsor

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Posted 08 November 2012 - 10:59 AM

I fired in a pit with my classes using the same method as you do. I don't mind the color variation.
I thought you sounded like you didn't want the lighter gray spots.
As for sealing them, carnueba floor wax applied with a show polish brush and rubbed with a soft cloth will give a nice shiny finish if that is what you are seeking. You can get this wax with some tints to it.
Hope this helps.


Marcia

#5 Isculpt

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Posted 08 November 2012 - 12:44 PM

I fired in a pit with my classes using the same method as you do. I don't mind the color variation.
I thought you sounded like you didn't want the lighter gray spots.
As for sealing them, carnueba floor wax applied with a show polish brush and rubbed with a soft cloth will give a nice shiny finish if that is what you are seeking. You can get this wax with some tints to it.
Hope this helps.


Marcia


Thanks Marcia for the carneuba floor wax suggestion. You were right; I don't like the light grey areas that look so dry, dusty, and drab, but I don't mind the darker greys and and I love the rich dark browns and intense blacks. I would love to find a workshop that would help me to understand the chemical processes and thus perhaps control the outcome a bit better, but I've not been able to find anything. I've read all the books on pit firing, alternative firing, burnishing, etc. I love the serendipity of pit firing, but a weeee bit more control would be really nice!!!

The attachments show desirable results and less desirable results. The slender snake pitcher and the frog pot show the desired color variations while the snake pot shows a more subdued, less varied coloration. (And no, these are not my pots. This is my husband's work as taught to him by his grandmother who learned from her grandmother, and on and on for centuries and millenia. He is now the Chief of his Nation and has few opportunities for pottery-making, but I've borrowed his techniques for my pieces. I just wish I understood the causes and effects of it better.)

#6 Isculpt

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Posted 08 November 2012 - 12:45 PM

I fired in a pit with my classes using the same method as you do. I don't mind the color variation.
I thought you sounded like you didn't want the lighter gray spots.
As for sealing them, carnueba floor wax applied with a show polish brush and rubbed with a soft cloth will give a nice shiny finish if that is what you are seeking. You can get this wax with some tints to it.
Hope this helps.


Marcia


Thanks Marcia for the carneuba floor wax suggestion. You were right; I don't like the light grey areas that look so dry, dusty, and drab, but I don't mind the darker greys and and I love the rich dark browns and intense blacks. I would love to find a workshop that would help me to understand the chemical processes and thus perhaps control the outcome a bit better, but I've not been able to find anything. I've read all the books on pit firing, alternative firing, burnishing, etc. I love the serendipity of pit firing, but a weeee bit more control would be really nice!!!

The attachments show desirable results and less desirable results. The slender snake pitcher and the frog pot show the desired color variations while the snake pot shows a more subdued, less varied coloration. (And no, these are not my pots. This is my husband's work as taught to him by his grandmother who learned from her grandmother, and on and on for centuries and millenia. He is now the Chief of his Nation and has few opportunities for pottery-making, but I've borrowed his techniques for my pieces. I just wish I understood the causes and effects of it better.)

#7 Isculpt

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Posted 08 November 2012 - 12:58 PM


I fired in a pit with my classes using the same method as you do. I don't mind the color variation.
I thought you sounded like you didn't want the lighter gray spots.
As for sealing them, carnueba floor wax applied with a show polish brush and rubbed with a soft cloth will give a nice shiny finish if that is what you are seeking. You can get this wax with some tints to it.
Hope this helps.


Marcia


Thanks Marcia for the carneuba floor wax suggestion. You were right; I don't like the light grey areas that look so dry, dusty, and drab, but I don't mind the darker greys and and I love the rich dark browns and intense blacks. I would love to find a workshop that would help me to understand the chemical processes and thus perhaps control the outcome a bit better, but I've not been able to find anything. I've read all the books on pit firing, alternative firing, burnishing, etc. I love the serendipity of pit firing, but a weeee bit more control would be really nice!!!

The attachments show desirable results and less desirable results. The slender snake pitcher and the frog pot show the desired color variations while the snake pot shows a more subdued, less varied coloration. (And no, these are not my pots. This is my husband's coil work made from clay dug from the same clay hole his people has used for centuries, as taught to him by his grandmother who learned from her grandmother, and on and on for centuries and millenia. He is now the Chief of his Nation and has few opportunities for pottery-making, but I've borrowed his techniques for my pieces. I just wish I understood the causes and effects of it better.)


Sorry the 2nd & 3rd photos didn't reproduce (??). Let's try again. The snake pot with the two war captains busts and the tri-legged snake pot burned as we like, but the light brown snake pot with the cross-hatching was just too monochromatic. It would be nice to be able to control the variations a bit better.




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