In the Studio: Creating Variations in Form

I explore themes of structure, shape, pattern, and multiples through 3D printing and plaster mold making. I’m drawn to forms featuring sharp angles, twisting, layering, and stacking. Combining these elements, I strive to create a sense of movement within a static object. Using molds and slip casting allows me to produce multiples of the same object, which I can then cut apart, stack, and attach in different ways. I like the freedom that molds give me to try new things and create variations of the same form.


It’s important to thoroughly mix the casting slip each time before pouring it into a mold. I use a heavy-duty drill with a mixer attachment because I’m usually mixing a large batch of slip in a 5-gallon bucket. Using a hand drill with a small attachment will overwork the small drill causing it to overheat and potentially break, so selecting the right tool is important. If the clay particles have settled to the bottom of the bucket, be sure to sieve the slip to evenly distribute the particles within the mixture.

Beginning with a 3-part plaster mold made from a 3D-printed cylindrical form, assemble the mold pieces and secure them with strong rubber bands or mold straps. When casting multiple molds to be joined together at once, the slip should be poured in at the same time. I design my molds with a gallery so that I can pour plenty of slip into the reservoir and not have to worry about checking on them or refilling the molds with slip as the water is absorbed by the plaster and the slip level lowers.

1 Pour slip into the mold. Let it set to reach the desired thickness, then pour it out.

2 Use a stiff rubber rib to cut away excess clay from the mold gallery.

The thickness and dryness of the plaster molds will determine how long you let the slip set up. Let the slip build up to the same thickness in each mold before pouring the slip out. Aside from visual discrepancy, uneven wall thickness can make it harder to line up the pieces when cutting and stacking slip-cast objects. Additionally, a connection point with a thick and a thin wall can also weaken the structure of your piece. I prefer my casts a bit on the thicker side, so I let the slip set up in my molds for 45 minutes to an hour before pouring it back into the original bucket (1).

About ten minutes after pouring the slip out of the mold, cut away excess clay from the mold gallery using a stiff rubber rib pressed against the flat area of the gallery. Wait until the clay is no longer sticky, but before the clay gets too hard. Once the clay is a firm leather hard, it will start to tear. Working from the center of the mold, press out toward the outer edge as you cut around the gallery. This will help to prevent the rim from warping (2). Allow the cast pieces to sit in the molds for one to two hours before removing them to avoid any ripping or warping upon removal.

Cutting and Stacking

The pieces will still need to stiffen up a bit more after being removed from the mold. Wait until each piece is leather hard before handling them too much (3). In addition to sketching stacking ideas, once the pieces are leather hard, I like to hold them up to one another and rotate them around to figure out how I want to deconstruct and reconstruct them. It’s fun to play with cutting apart slip-cast objects—it feels low risk because I can always cast more.

3 Allow the pieces to set up a bit before removing to avoid any ripping or warping.

4 Mark a dashed line around the form, then cut along it with a sharp knife.

5 Having scored and slipped the sections, stack and attach the pieces together.

6 Fill in the gaps between the pieces using a paint brush and casting slip.

Once I’ve figured out where I want to make my cuts, I use a ruler to make even dashed lines on the surface all the way around the form. These will be the guidelines for cutting. Next, using a sharp knife, cut along the marked points (4). Apply casting slip to the rim of each of the objects to be stacked and score the edges using a scoring tool. Stack the cut pieces together, lining up the slipped and scored edges (5). I leave the mold seams on my cast pieces at this stage and use them to indicate where to match up another piece. When combining pieces, press down on the most recently added part to strengthen the seam. There will be a visible line where the pieces were stacked and attached together. To create a more seamless appearance, use a paint brush to apply wet casting slip into the seam, filling any gaps (6).

Wait for the final object to dry to a hard leather hard. Use a knife to trim the seams and remove any bumps and imperfections (7). Once the piece is nearly dry, use a scouring pad to smooth out larger bumps and ridges (8).

7 Using an X-Acto knife, trim the seams and any imperfections.

Finally, while the piece is a dry leather hard, flatten and smooth the rim and the bottom of the pot by gently pressing it down onto a wet canvas surface, moving the pot in a figure-8 motion. Use a finishing sponge for a final smoothing over the entire piece. To finish the pot, use a sponge to round the rim. Allow the piece to fully dry. I fire my pieces to cone 6 in an electric kiln.

8 Once the piece is nearly dry, use a scouring pad to smooth out any bumps and ridges.

Hayley Reed received a BFA from The School of the Art Institute of Chicago in 2018. She currently lives in Seattle, Washington, and is working as a studio assistant for Deborah Schwartzkopf at Rat City Studios. In addition to slip casting, Hayley has recently been exploring her relationship to Judaism by making celebratory religious objects with clay. When Hayley isn’t at the studio, she likes spending time with her dog, Ziva. To learn more, visit or on Instagram @Hayley_Bella.


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