Some amount of cleanup is unavoidable after atmospheric firings. Here are the tools and techniques that prove most effective for this stage of Neil Celani’s low-fire work.
The many benefits of soda firing at low temperatures attracted me to this firing range. For one, there is less wear-and-tear on the kiln and kiln furniture. Less build up of soda glaze means less cleanup, which inevitably deteriorates the kiln with the constant grinding and scraping required for maintenance after each firing. This fact also applies to the pots themselves. I find the cleanup to be much less laborious with low-temperature soda work than my experience with cone-10 soda work. I have spent countless hours grinding and sanding work out of the cone-10 soda kiln. The thick soda glaze that deposits on the work is gorgeous, but is an absolute pain to grind off of areas where it is undesirable.
My experience with cleaning up soda-fired earthenware work has been a different story. Note: Always wear a properly fitted respirator and safety glasses while sanding and grinding (1). Nearly every pot that comes out of a low-fire soda kiln needs a minimal amount of post-firing cleanup: wads usually fall off right out of the kiln and the slipped, raw clay, or terra-sigillata surfaces need a quick, light sanding with sandpaper ranging from 120 to 400 grit. I use different types of sandpaper. Wet/dry sandpaper is one of my go-to standards, and ultra flexible, film-backed sandpaper is long lasting, extremely useful, and can be easily wrapped around a finger to sand places like the inside of a handle (2) or around all those hard-to-reach nooks and crannies.
I also cut apart belt sander belts as the fabric backing outlasts the abrasive grit and prevents having to deal with inevitable crumpled and torn scraps of paper-backed sandpaper. Start with the coarsest grit and progressively work up to the finer grit in order to achieve a buttery smooth clay surface. I use my hands as guides while sanding by continually feeling around the pot for burrs or rough spots that need sanding.
Handles, lip rims, and feet are very important to pay close attention to when cleaning up a pot after firing. Care must be taken when sanding to not strip away the surface of the pot too much—the coarser the grit, the more likely it is to visibly scratch the surface (3, 4). Diamond pads are an abrasive option that can work well in some instances but can quickly mar the surface if extreme care is not taken. Diamond pads are used with water and can be found in 60 to 3000 grit.
On rare occasions, I pull out a handheld rotary tool to grind away a stuck wad or unwanted soda-glaze deposit. I recommend using a variable-speed handheld rotary tool, and I find that the slower speeds allow for more control and do not damage the work (5, 6). I use a variety of diamond bits that make quick work of clean up.
After grinding and sanding, I sometimes apply a coat of food-safe mineral oil on the slipped and terra sigillata-coated wares and let it sit overnight. This is especially useful for the very dry clay surfaces to help bring out the subtle flashing colors and give the pot a nice feel.
Finally, each pot is washed with soap and water to remove any dust, debris, or excess mineral oil before being sent out into the world. The final cleanup of soda-fired work, sometimes called cold finishing, can have a dramatic impact on the look and feel of the final piece. With patience and care, a soda-fired pot can be a wonderful, unique, tactile experience and will share its story to the keen-eyed individual in the know.
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Some amount of cleanup is unavoidable after atmospheric firings. Here are the tools and techniques that prove most effective for this stage of Neil Celani’s low-fire work.
The many benefits of soda firing at low temperatures attracted me to this firing range. For one, there is less wear-and-tear on the kiln and kiln furniture. Less build up of soda glaze means less cleanup, which inevitably deteriorates the kiln with the constant grinding and scraping required for maintenance after each firing. This fact also applies to the pots themselves. I find the cleanup to be much less laborious with low-temperature soda work than my experience with cone-10 soda work. I have spent countless hours grinding and sanding work out of the cone-10 soda kiln. The thick soda glaze that deposits on the work is gorgeous, but is an absolute pain to grind off of areas where it is undesirable.
My experience with cleaning up soda-fired earthenware work has been a different story. Note: Always wear a properly fitted respirator and safety glasses while sanding and grinding (1). Nearly every pot that comes out of a low-fire soda kiln needs a minimal amount of post-firing cleanup: wads usually fall off right out of the kiln and the slipped, raw clay, or terra-sigillata surfaces need a quick, light sanding with sandpaper ranging from 120 to 400 grit. I use different types of sandpaper. Wet/dry sandpaper is one of my go-to standards, and ultra flexible, film-backed sandpaper is long lasting, extremely useful, and can be easily wrapped around a finger to sand places like the inside of a handle (2) or around all those hard-to-reach nooks and crannies.
I also cut apart belt sander belts as the fabric backing outlasts the abrasive grit and prevents having to deal with inevitable crumpled and torn scraps of paper-backed sandpaper. Start with the coarsest grit and progressively work up to the finer grit in order to achieve a buttery smooth clay surface. I use my hands as guides while sanding by continually feeling around the pot for burrs or rough spots that need sanding.
Handles, lip rims, and feet are very important to pay close attention to when cleaning up a pot after firing. Care must be taken when sanding to not strip away the surface of the pot too much—the coarser the grit, the more likely it is to visibly scratch the surface (3, 4). Diamond pads are an abrasive option that can work well in some instances but can quickly mar the surface if extreme care is not taken. Diamond pads are used with water and can be found in 60 to 3000 grit.
On rare occasions, I pull out a handheld rotary tool to grind away a stuck wad or unwanted soda-glaze deposit. I recommend using a variable-speed handheld rotary tool, and I find that the slower speeds allow for more control and do not damage the work (5, 6). I use a variety of diamond bits that make quick work of clean up.
After grinding and sanding, I sometimes apply a coat of food-safe mineral oil on the slipped and terra sigillata-coated wares and let it sit overnight. This is especially useful for the very dry clay surfaces to help bring out the subtle flashing colors and give the pot a nice feel.
Finally, each pot is washed with soap and water to remove any dust, debris, or excess mineral oil before being sent out into the world. The final cleanup of soda-fired work, sometimes called cold finishing, can have a dramatic impact on the look and feel of the final piece. With patience and care, a soda-fired pot can be a wonderful, unique, tactile experience and will share its story to the keen-eyed individual in the know.
the author Neil Celani contributed this excerpt to Justin Rothshank’s book, Low-Fire Soda, published by the American Ceramic Society and available in the Ceramic Arts Network Shop: https://mycan.ceramicartsnetwork.org/s/product-details?id=a1B3u000009udqwEAA.
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