Cathi Jefferson’s stacking jar sets were inspired by a late night conversation after a wood firing and her interest in exploring natural forms as decorative motifs.

The inspiration for these stacking jars occurred during a residency at the Banff Centre for the Arts. While sleep deprived after a wood firing, sitting in the library with my friend Jana Zylich, we somehow got talking about spice jars and how people like to have them sitting out to look at and for easy access, but they take up too much counter space. The conversation progressed to how it would make sense to just stack them. I started sketching some thoughts up right then, and when I got home, I tried the different ideas I had drawn. One of these original sketches is the basis for the stacking jars I’m still making today.

Planning Sets for Stacking

Through trial and error I eventually figured out that I need only an ounce difference in weight between the clay balls used for the different levels. I use 10 oz. for the largest piece, 9 oz. for the next size down, 8 oz. for the smaller size, 7 oz. for the smallest jar, and 6 oz. for the lid. I usually make six of each size at a time so there’s a continuity in the rhythm. I try to make each jar the same height: about 2½ inches tall. The uniformity in height helps the components of the set look like they belong together.

Once I finish throwing a round cylinder, I run the corner of my rib up the outside of the pot to create a varied surface (1). This serves an ergonomic function; if you’re holding one of the jars, your fingers will fit into the grooves the rib makes, making it easier to grip. I also add this line because I don’t want my work to look like it’s coming out of a mold from a factory. This line gives my pieces a sense of volume, like the pot wants to breathe out. It gives a sense that there is energy coming out of the pot

1 After throwing a cylinder for the largest jar, use a rib to create a varied surface.2 Use a clothes pin to press down on half of the cylinder rim to create a lid gallery.

3 Square up the form by running a finger up the inside wall of the pot in four spots.4 Push out the bottom inside corners, then push in each side to square up the base. Repeat the process for the other jars.

To make the gallery for smaller pots, I use a clothes pin rather than a rib. I hold the clothes pin with the end facing outward, pressing down about half way into the rim creating a gallery about a ¼ inch deep (2). By holding the clothes pin at an angle, I create a rim with a flat gallery and a lip that leans slightly outward so that it doesn’t trap the lid.

Once I’ve made the gallery I square the form by running my middle finger up the wall on the inside of the pot in four equidistant places (3). When I reach the gallery I also push outward to make sure the top of the corner is also squared up. I use a Giffin Grip when I throw and have marks I’ve added that indicate where the corners of a square are. Although I don’t want perfectly straight lines (there are no straight lines in nature), each piece needs to fit together.

5 To make the lid, throw a V-shaped bowl, then shape to a plate-like domed curve with a flattened outside edge.6 Place the roughly cut lid on the top jar and run a fingernail around the rim to mark the clay to cut off.

7 Use a Surform to cut away the excess clay from the lid up to the guideline made with your fingernail. 8 Smooth and flatten the sides of the lid, check the fit, and trim more if needed, then place the lid on the jar.

To smooth the bottom edge and create a shadow under each piece, I press my thumb up compressing around the base. When I get a set of jars that fit each other, I stamp the bottom left-hand corner of each jar with my chop so that I don’t lose track of the alignment. I always dry and fire them stacked together.

For the Top Jar

To make the lid for the stack, start by throwing a V-shaped bowl on the wheel, then use a rib to shape this to a plate-like domed curve with a flattened outside edge (5), and cut it off the wheel.

When the lid is soft leather hard, I make the knob by squishing the extra clay at the base to make it taller. To fit the lid, I first put it on top of the smallest, top-most jar, marking the underside with a needle tool to indicate what I need to cut off. I also mark the front left corner of the lid, making it easier to align it with the side of the jar I’ve already stamped with my chop.

9 Remove all of the cutout diamond shapes by poking them with a stick. 10 Smooth the entire piece with a finishing sponge to blunt any sharp edges.11 After the bisque firing, use graphic art tape as a resist for the glaze.

With the lid placed back on the jar, I run my fingernail around the top to help indicate how much material needs to be removed in order for the lid to sit down into the gallery (6). I use a Surform to cut away the excess clay from the lid (7). I keep tweaking the lid to fit by marking it with my fingernail, trimming off a little bit at a time, flattening down the sides, and repeating this process until it fits (8), then finally smoothing it off with a metal rib. Once the lid fits, I shape the knob by trimming away extra clay until I achieve the right shape (9–11). The edges of the lid as well as the edges of the knob have a slight curve rather than sharp angles because I want the lid to retain the sense of softness and volume in the rest of the form.

12 The finished, fired stacking jars, ready to be unloaded from the kiln. The wadding will separate easily from the pots. 13 Lifting off the top pots in a finished stacking set to show the glazed interior. A four-piece arbutus leaf stacking spice-jar set, wheel thrown and altered, fired to 2374°F (1300°C) in a salt kiln.

Surface Plus Form United

In addition to making all the parts fit together, I also want the decoration to work with the form. My work is inspired mostly by nature, but I also think about the overall piece when I decide what images I want to use as decoration. The decoration needs to flow from side to side as well as from bottom to top. For instance, the branches of the leaves will flow from one jar to the next, starting at the bottom and working its way up and over the sides with a leaf or two reaching up on to the lid to make it easy to know which way it fits.

I use various flashing slips on the exterior of the pots, glaze the interior, and fire them in my salt kiln to 2374°F (1300°C). I add a little alumina hydrate to my wax resist, and when I stack the jars for firing, I brush the galleries with this resist. I also put a small ball of wadding in each corner of the galleries and a coil of wadding between the topmost jar and the lid (12, 13). This separates and elevates each piece so they can be fired together, but not fuse to each other, and hopefully enable the color and texture of each piece to relate to the one next to it.

Cathi Jefferson is a potter and instructor who lives near Duncan on Vancouver Island, British Columbia, Canada. See more of her work at www.cathijefferson.com.

Topics: Handbuilding Techniques

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