For the last 20 years, I have worked as a ceramic artist and chef. To me, food and pottery are inseparable. They are symbiotic catalysts for connection. Using a specific geometric language, I design utilitarian vessels for the dinner table. Just as technological advances such as molecular gastronomy have shifted the culinary landscape, so too have emergent technologies redefined the world of craft.
In my studio practice, I implement tools such as digital modeling and 3D printing. These advancements provide a unique refinement of line and form. As I search for my own definition of “precisely handmade,” I strive to remain mindful of the rich ceramics tradition on which my work builds. I find there is something beautiful when crisp, hard edges submit themselves to the soft rolling flux of a soda-kiln firing. This give and take, this ever-elusive pursuit of balance, is what I chase consistently.
Design
I design my forms on the computer first, using a modeling software called Rhino. When I start a new design, I focus on two planes, the top and the front. I start in the top view and draw a geometric design out from the center to the perimeter of the pot—in this case, an 8-sided-star shape. Then, from the front view, I draw a half silhouette of the vessel, also from the center. I use a function called “Rail Revolve” to sweep the silhouette line around the perimeter line. Finally, I cap the form so that it is solid and ready to export to the slicer (1).
Slicing software prepares the design for the 3D printer. It creates a language called g-code, which tells the printer what to do. I use a slicing software called Cura. While there are many options out there, I like Cura because it’s user friendly and, more importantly, free (2).
After I check that the g-code all looks good, the file is ready for the printer. There are a ton of options out there when it comes to 3D printers, at a myriad of price points. I use a Creality CR-10 Pro to print PLA filament (plastic). Its approachable price and superb print resolution make it a tool worth the investment. Regardless of the printer being used, I have found that the most important factors in achieving a successful print are having a level bed and appropriate temperatures for both the bed and nozzle (3).
Mold Making
Once the prototype is successfully printed, it’s time to prepare for mold making. First, cut out a platform 1½ inches larger than the base of the prototype, center the form, and trace it. I like to use MDF for the base because it’s inexpensive and easy to work with. A ware board or scrap piece of plywood will work fine, too (4). Ensuring the piece is centered will allow the plaster to cast evenly around it. Next, glue the form to the board and let it set overnight. I use a technique called “spot gluing”—adding just a few pea-sized dots of wood glue to the form. This will allow it to adhere to the board for part one of the mold, but allow it to be separated with a firm tap for the second part (5). I seal the form with Kilz 2 latex primer, making sure to fill the seam between the prototype and base board (6). This prevents plaster from seeping between the model and wooden base. I normally apply 2–3 coats, sanding in between each coat.
Once the model has been primed and sanded, it’s time to apply mold soap. Mold soap allows the form to pull away from the cured plaster without sticking. I use Murphy’s Oil Soap. Mix up a solution with a ratio of roughly 70% soap and 30% water. Then, with a brush, paint the soap all over the form (7). Let the foaming soap sit for a few minutes, then wipe it off with a damp sponge and bucket of clean water, repeating this process 2–3 times. When finished, the form should feel waxy, like a candle.
Next, set up cottle boards (which have also been mold soaped) and clamp them in place. Make sure that they are square and flush against the base. On larger molds, like this one, I clamp the top and bottom of the cottle boards for extra strength (see 8). Now, it’s time to seal the box with clay to create a watertight container to hold the liquid plaster. Roll out coils roughly the diameter of a pencil and carefully press them into the four seams on the bottom and the four seams up the corners. Then, with a wet finger, compress both sides of all the coils, adhering them to the cottle boards (8).
Plaster
Carefully weigh out the plaster and cold water. While wearing a respirator, slake the plaster into the water (9), let it soak for 3 minutes, then stir it for 3 minutes by hand. When stirring, use a steady, consistent motion. This will help mitigate air bubbles. After 3 minutes, tap the bucket on the ground to remove additional air bubbles and carefully pour the plaster, slowly and steadily, into one corner of the mold box, letting it gradually come up and over the prototype (10). If you have a clay trap in your sink, wash out the bucket immediately, if not the residual plaster can be knocked out with a rubber mallet once it’s cured in the bucket. Then place your hand on the surface of the liquid plaster. Shake your hand like you’re waving to someone, but let it remain on the surface of the plaster (11). This allows any additional air bubbles to rise to the surface. The plaster takes about 30 minutes to cure. It will get very warm. Once it starts to cool off, it is safe to remove the cottles. A slight tap of the finger should free them.
This mold has two parts. To make the second section, flip over the first section of the mold that was just cast, and use a round trimming tool to make 3 half-sphere registration keys in the first half of the mold (see 12). Next, glue on the second piece of the prototype, and repeat all previous steps. When casting the second part of the mold, the half-circle keys will fill with plaster and function as a registration for proper alignment of the two sections when using the mold.
When preparing the mold to cast the second plaster section, I also prefer to brush straight mold soap onto the plaster and model, because plaster loves to stick to plaster. Additionally, on the second pour, stop just before you get to the top of the form. By doing so, you’ll maintain an opening so that you can pour slip in and out of the mold (12). Once both parts have cured, remove the cottles and prototype and set the molds to dry in a warm area. This will take a few days. When the molds are fully dry, clean them with white vinegar to remove any remaining mold soap.
Slip Casting
Strap the two halves of the mold together using the keys for alignment. Set up on a sturdy table, making sure the mold is level. Then, add a small clay ring to the top of the mold to act as a waster (reservoir) and fill the mold with casting slip (13). Casting slip is liquid clay held in suspension. As the liquid slip sits against the dry plaster, water is slowly pulled out of the slip and into the plaster, turning the liquid slip into solid clay walls adhered to the plaster. The longer that the slip sits in the mold, the thicker the walls become. When you reach your desired wall thickness, pour out the remaining slip, trim off the waster and let the mold dry upside down for about an hour. Carefully pry open the top of the mold with a wooden rib and allow the clay form to set up to leather hard before removing it from the mold (14). The greenware dries for a couple days before it is bisque fired. Use this time to clean up any seams.
Glazing
When the wares come out of the bisque firing, they are porous and ready to accept glaze. I use a palette of about a dozen glazes that have been slowly formulated and adjusted over the years. My best advice for finding new and exciting glazes is test, test, test (15)! I prefer to spray my glazes on larger forms and dip the smaller ones. Spraying the glaze allows for a nice gradient of color, which creates more variation on the finished surface (16). Some of the work also gets pinstriped with thin tape to resist the glaze. After the bisqueware has been glazed, add small balls of wadding to the bottoms of each piece, make cone packs, and load the soda kiln (17).
Firing
Once the work is loaded, I candle the kiln overnight and fire slowly through quartz inversion. I like to hit body reduction at cone 010 for about an hour, then keep medium reduction the rest of the way. At cone 6, I get my soda mixture ready—normally about 3–4 pounds of soda ash to 2 gallons of cold water. The whole mixture goes into a metal garden sprayer. Wearing a respirator, start spraying at cone 7, hitting the ports for about 5–7 seconds each (18). Keep a bucket of cold water nearby to dip the sprayer nozzle into between sprays. Continue this until the kiln reaches cone 10 or until the soda mixture is gone (normally about the same time). When cone 10 is down and cone 11 is soft (starting to bend), I pull out the damper fully and oxidize the chamber for 5 minutes. This little bit of oxidation at the end helps brighten the glaze colors. Then, I slow cool from 1900–1300°F (1038–704°C) to encourage crystal growth. The kiln takes a couple days to cool. Unloading always feels like Christmas morning; I spend some time with each piece, evaluating, contemplating, and ultimately responding. Then, I start the entire process over again, chasing the next exciting idea.
Britton Thorp lives in Austin, Texas, where he maintains his studio practice and teaches ceramics at St Stephens Episcopal School. He received his MFA from Syracuse University in 2021 and his BFA from Ohio University in 2008. For more information, check out his online shop at www.brittonthorpceramics.com and follow him on Instagram @brittonthorpceramics.
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For the last 20 years, I have worked as a ceramic artist and chef. To me, food and pottery are inseparable. They are symbiotic catalysts for connection. Using a specific geometric language, I design utilitarian vessels for the dinner table. Just as technological advances such as molecular gastronomy have shifted the culinary landscape, so too have emergent technologies redefined the world of craft.
In my studio practice, I implement tools such as digital modeling and 3D printing. These advancements provide a unique refinement of line and form. As I search for my own definition of “precisely handmade,” I strive to remain mindful of the rich ceramics tradition on which my work builds. I find there is something beautiful when crisp, hard edges submit themselves to the soft rolling flux of a soda-kiln firing. This give and take, this ever-elusive pursuit of balance, is what I chase consistently.
Design
I design my forms on the computer first, using a modeling software called Rhino. When I start a new design, I focus on two planes, the top and the front. I start in the top view and draw a geometric design out from the center to the perimeter of the pot—in this case, an 8-sided-star shape. Then, from the front view, I draw a half silhouette of the vessel, also from the center. I use a function called “Rail Revolve” to sweep the silhouette line around the perimeter line. Finally, I cap the form so that it is solid and ready to export to the slicer (1).
Slicing software prepares the design for the 3D printer. It creates a language called g-code, which tells the printer what to do. I use a slicing software called Cura. While there are many options out there, I like Cura because it’s user friendly and, more importantly, free (2).
After I check that the g-code all looks good, the file is ready for the printer. There are a ton of options out there when it comes to 3D printers, at a myriad of price points. I use a Creality CR-10 Pro to print PLA filament (plastic). Its approachable price and superb print resolution make it a tool worth the investment. Regardless of the printer being used, I have found that the most important factors in achieving a successful print are having a level bed and appropriate temperatures for both the bed and nozzle (3).
Mold Making
Once the prototype is successfully printed, it’s time to prepare for mold making. First, cut out a platform 1½ inches larger than the base of the prototype, center the form, and trace it. I like to use MDF for the base because it’s inexpensive and easy to work with. A ware board or scrap piece of plywood will work fine, too (4). Ensuring the piece is centered will allow the plaster to cast evenly around it. Next, glue the form to the board and let it set overnight. I use a technique called “spot gluing”—adding just a few pea-sized dots of wood glue to the form. This will allow it to adhere to the board for part one of the mold, but allow it to be separated with a firm tap for the second part (5). I seal the form with Kilz 2 latex primer, making sure to fill the seam between the prototype and base board (6). This prevents plaster from seeping between the model and wooden base. I normally apply 2–3 coats, sanding in between each coat.
Once the model has been primed and sanded, it’s time to apply mold soap. Mold soap allows the form to pull away from the cured plaster without sticking. I use Murphy’s Oil Soap. Mix up a solution with a ratio of roughly 70% soap and 30% water. Then, with a brush, paint the soap all over the form (7). Let the foaming soap sit for a few minutes, then wipe it off with a damp sponge and bucket of clean water, repeating this process 2–3 times. When finished, the form should feel waxy, like a candle.
Next, set up cottle boards (which have also been mold soaped) and clamp them in place. Make sure that they are square and flush against the base. On larger molds, like this one, I clamp the top and bottom of the cottle boards for extra strength (see 8). Now, it’s time to seal the box with clay to create a watertight container to hold the liquid plaster. Roll out coils roughly the diameter of a pencil and carefully press them into the four seams on the bottom and the four seams up the corners. Then, with a wet finger, compress both sides of all the coils, adhering them to the cottle boards (8).
Plaster
Carefully weigh out the plaster and cold water. While wearing a respirator, slake the plaster into the water (9), let it soak for 3 minutes, then stir it for 3 minutes by hand. When stirring, use a steady, consistent motion. This will help mitigate air bubbles. After 3 minutes, tap the bucket on the ground to remove additional air bubbles and carefully pour the plaster, slowly and steadily, into one corner of the mold box, letting it gradually come up and over the prototype (10). If you have a clay trap in your sink, wash out the bucket immediately, if not the residual plaster can be knocked out with a rubber mallet once it’s cured in the bucket. Then place your hand on the surface of the liquid plaster. Shake your hand like you’re waving to someone, but let it remain on the surface of the plaster (11). This allows any additional air bubbles to rise to the surface. The plaster takes about 30 minutes to cure. It will get very warm. Once it starts to cool off, it is safe to remove the cottles. A slight tap of the finger should free them.
This mold has two parts. To make the second section, flip over the first section of the mold that was just cast, and use a round trimming tool to make 3 half-sphere registration keys in the first half of the mold (see 12). Next, glue on the second piece of the prototype, and repeat all previous steps. When casting the second part of the mold, the half-circle keys will fill with plaster and function as a registration for proper alignment of the two sections when using the mold.
When preparing the mold to cast the second plaster section, I also prefer to brush straight mold soap onto the plaster and model, because plaster loves to stick to plaster. Additionally, on the second pour, stop just before you get to the top of the form. By doing so, you’ll maintain an opening so that you can pour slip in and out of the mold (12). Once both parts have cured, remove the cottles and prototype and set the molds to dry in a warm area. This will take a few days. When the molds are fully dry, clean them with white vinegar to remove any remaining mold soap.
Slip Casting
Strap the two halves of the mold together using the keys for alignment. Set up on a sturdy table, making sure the mold is level. Then, add a small clay ring to the top of the mold to act as a waster (reservoir) and fill the mold with casting slip (13). Casting slip is liquid clay held in suspension. As the liquid slip sits against the dry plaster, water is slowly pulled out of the slip and into the plaster, turning the liquid slip into solid clay walls adhered to the plaster. The longer that the slip sits in the mold, the thicker the walls become. When you reach your desired wall thickness, pour out the remaining slip, trim off the waster and let the mold dry upside down for about an hour. Carefully pry open the top of the mold with a wooden rib and allow the clay form to set up to leather hard before removing it from the mold (14). The greenware dries for a couple days before it is bisque fired. Use this time to clean up any seams.
Glazing
When the wares come out of the bisque firing, they are porous and ready to accept glaze. I use a palette of about a dozen glazes that have been slowly formulated and adjusted over the years. My best advice for finding new and exciting glazes is test, test, test (15)! I prefer to spray my glazes on larger forms and dip the smaller ones. Spraying the glaze allows for a nice gradient of color, which creates more variation on the finished surface (16). Some of the work also gets pinstriped with thin tape to resist the glaze. After the bisqueware has been glazed, add small balls of wadding to the bottoms of each piece, make cone packs, and load the soda kiln (17).
Firing
Once the work is loaded, I candle the kiln overnight and fire slowly through quartz inversion. I like to hit body reduction at cone 010 for about an hour, then keep medium reduction the rest of the way. At cone 6, I get my soda mixture ready—normally about 3–4 pounds of soda ash to 2 gallons of cold water. The whole mixture goes into a metal garden sprayer. Wearing a respirator, start spraying at cone 7, hitting the ports for about 5–7 seconds each (18). Keep a bucket of cold water nearby to dip the sprayer nozzle into between sprays. Continue this until the kiln reaches cone 10 or until the soda mixture is gone (normally about the same time). When cone 10 is down and cone 11 is soft (starting to bend), I pull out the damper fully and oxidize the chamber for 5 minutes. This little bit of oxidation at the end helps brighten the glaze colors. Then, I slow cool from 1900–1300°F (1038–704°C) to encourage crystal growth. The kiln takes a couple days to cool. Unloading always feels like Christmas morning; I spend some time with each piece, evaluating, contemplating, and ultimately responding. Then, I start the entire process over again, chasing the next exciting idea.
Britton Thorp lives in Austin, Texas, where he maintains his studio practice and teaches ceramics at St Stephens Episcopal School. He received his MFA from Syracuse University in 2021 and his BFA from Ohio University in 2008. For more information, check out his online shop at www.brittonthorpceramics.com and follow him on Instagram
@brittonthorpceramics.
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