So I decided to give my North Star 4″ extruder a workout this week, building two large 20lb. coil stoneware planters. I actually made the bases for the planters last week, using coils as well, then ‘threw’ each base on the wheel to smooth out what would eventually be the interior surface. I left the bases lightly covered in plastic on plaster bats for several days to get leather-hard.
The first leather-hard base was placed on the banding wheel, then scored and slipped, ready to receive the first coil. As each coil row was added, I used a wooden modeling tool to blend one row of coil with the next, then smoothed the outer sides with a small plastic rib.
The process was repeated until I had added several rows of coils and gradually widened the form to a final upper diameter of 17″. Since my extruder is installed right next to the work table, the process of cranking out coils, application, and building the form went quickly and efficiently.
Selecting just the right coil-sized die was essential for quick work, and keeping a bucket beneath the extruder made cleanup a lot easier.
Halfway through the building process I stopped building to allow the coils to set up, wedged more clay for the upper half of the form, and made some decorative tiles to later affix to the outside of the planter.
After the full height of the form was reached, I added one more coil row, this time using a slightly greater width coil to serve as the planet’s rim.
Lastly, I added some decorative surface patterns and attached the decorative tiles I had made earlier. The planter on the right below is shown further along in the drying process, and after the base was smoothed with a damp sponge.
Constructing a large slab-built milk-can requires a bit of planning and plenty of work space. Using bristol board sheets to construct a mock-up of the overall form and I then took it apart to use the pieces for templates. The large slab roller in work made quick work of rolling the largest template shape, which was roughly 30″ by 17″ – for the barrel of the milk can. For transport, I rolled the 15 lb. slab within heavy canvas and plastic sheeting, then placed it inside a rolling suitcase to bring it to my home studio. Once in the studio, I unrolled the soft slab to allow it to set up a bit.
Once the slab was no longer soft, I draped it over a 5 gallon bucket and a wheel bat placed at either end, with heavy canvas between the clay and the supporting structure to allow the clay to set up in a large arc without sticking to the bucket and bats.
The slab sat like this for several hours, checked on from time to time, to determine when it was strong enough to hold its own weight. Once it was strong enough, I stood it up and began to form the cylinder for the barrel of the can. While the large slab had been setting up, I had rolled a smaller slab for the base of the can and let it firm up on a plaster bat, so when the barrel of the can was ready, I attached it to the base and positioned the form on a masonite board.
After wrapping the form in plastic sheeting so it wouldn’t get too dry, I began to roll and cut the slabs for the upper sections of the milk can using the bristol board templates.
After forming the upper sections of the can I placed each part on a plaster bat to set up. Getting these sections leather hard didn’t take too long, because the warm sun and gentle breeze on the back patio provided the perfect drying environment.
After the upper sections were firm enough, I attached them to the barrel, and added a coil to the joint of each upper section, then a handle on either side.
Wrapping the lower portion of the can in plastic allowed the upper section to dry a bit more so some fine tuning of the form’s surface could be dealt with at a later time. Lastly, I took some measurements to record the amount of shrinkage at leather hard -and later at bisque and glaze- since I’d never made this form before.