| From the pages of Pottery Making Illustrated
Twisted: Are You Sure That Was Extruded? by David Hendley
Three finished lotion jars, 7 inches in height, handbuilt using extruded parts, with added feet of unglazed dark brown clay and multicolored slip-glazes. Pump dispensers added after glaze firing.
| I have been using extruders in my clay work since 1974, after I built my first extruder and made my first dies. I immediately saw the potential for making new forms through extruding, and I’ve always had an extruder in my studio that I use on a regular basis. Of all the pieces I make, the extruder is used for about two-thirds of them—to produce either the main form itself or an added element for a wheel-thrown vessel. Even my pulled handles start out as extrusions.
Producing work with an extruder seems like it would enable you to make dozens of items quickly, but just the opposite is often true. Because of all the measuring, cutting, and joining, an extruded pot can require more time to make than a similar, thrown pot, but for some forms, extruding is the most expedient way to go.
As for the dies, manufacturers offer many configurations; however, if you have more than a passing interest in using an extruder, I’d suggest making your own. Designing and making the die is part of the creative process and requires thinking from a different perspective since it’s the negative space of the die that produces the form. With practice, you’ll soon be able to shift your spatial thinking to where you can easily picture the three-dimensional piece you’ll get from the shape outline cut into a two-dimensional die, and vice versa. In fact, after spending a lot of time and thought designing dies, I often look at everyday objects and mentally picture what the die needed to make them might look like.
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Making a Lotion Dispenser
The form for the lotion dispenser is made with a two-part die that produces a 2½-inch square tube. Hollow square tubes are among the most common shapes that are extruded, but twisting the extrusion gives a sense of movement to the finished pot. |
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| 1. Twist the extrusion as it exits the extruder. | 2. Use a piece of monofilament fishing line to cut the extrusion.
| 3. Allow extrusions to set up. Turn over after an hour. | 4. When leather hard, cut extrusions to length.
| 5. Brush on underglazes or vitreous engobes if desired.
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Lotion dispenser pumps, available from most ceramic supply stores, come in a variety of styles and colors. You’ll need to purchase those before you attempt this project so that you can make appropriate design and color choices. The collars need to be attached with adhesive after the glaze firing—check with your supplier for the best combination.
To make the lotion dispenser, load the die into the extruder and fill the extruder barrel with clay. To minimize air bubbles in the extrusion, shape the clay so it slides easily yet snugly down the barrel. Pull down on the lever of the extruder with one hand while twisting the clay as it exits the extruder with the other hand (figure 1). To keep a hollow form from collapsing in on itself as it is twisted, keep your hand right below the die, twisting the clay just as it exits the extruder, and move your hand back up as every inch or so of clay comes out. Any faint thumb indentations left on the clay from the twisting process will not be perceptible in the finished piece. While this process feels awkward at first, and takes some practice as well as a wide reach, I have no trouble doing the job by myself. You may want to have an assistant slowly pull the handle while you practice the first few times. It also takes some practice to get a feel for how much pressure is required to twist the clay as it comes from the extruder. Not much pressure is required, and most beginners twist too much rather than too little.
When you have a long enough extrusion, cut it loose with a piece of monofilament fishing line. Wrap the fishing line around the extrusion, and allow one end of the line to dig into the clay, which holds it in place. Use one hand to pull the other end of the line through the clay while the other hand supports the extrusion as it is cut loose (figure 2).
I always make at least 10 or 12 dispenser pots at a time because of the
significant set-up and clean up time when extruding through a two-part
hollow die. Twisted extrusions are cut off in 18-to-20 inch long
sections and set aside to firm up on a table (figure 3). In average
weather, I allow the sections to dry for about an hour and then flip
and allow to dry for another hour. Measure each extrusion and divide it
into three 6–7 inch long pieces. Use a fettling knife to cut each
extrusion (figure 4).
For my glazing technique, I apply slip
glazes to the sections of twisted square extrusions before adding the
tops and bottoms (figure 5). Allow the painted surfaces to dry for
several hours before handling and continuing with construction. (After
bisque firing, I glaze the top and insides of the dispensers.)
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6. Round corners and
smooth edges of squares.
| 7. Cut arches into the top
and bottom of the form.
| 8. Trim the bottom slab
flush with the sides.
| 9. Use a tool to compress
and bevel the seam. | 10. Cut a 1-inch hole in the
top for the pump.
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Once the slip glaze is dry, roll out slabs for the tops and bottoms of the dispensers. The slab should be slightly thicker than the walls of the extrusion. Cut the slab into 2½-inch squares, then round and smooth the edges and corners of each square (figure 6). Roll each square again to make it slightly thinner and wider (about 2¾ inches square). I roll past the edges to create a softer and slightly wavy edge.
Next, cut raised arches into the top end of the extruded section (figure 7). On the bottom of the pot, cut the arch so the four corners become the feet of the piece. Score and slip the bottom edges, attach the bottom slab (figure 8) and trim the edges flush with a cheese slicer or fettling knife. Roll the handle of a fettling knife along the edges of the bottom at a 45° angle to reinforce the joint and bevel the bottom slab (figure 9).
Add the top slab but don’t trim it, leave the overhang as a design element. Roll the top back and forth on the table to secure the join, allow to dry for about an hour, then cover with plastic and leave overnight to equalize the moisture.
On the following day, use a piece of 1-inch tubing to make a hole in the center of the top slab for the lotion pump (figure 10). After the glaze firing, a glue-on collar and lotion pump collar will complete the pot. |
Making a
Rope-top Bucket
Pots with twisted coil rims and handles have been made since ancient
times. Lots of beginning pottery students try making pots with twisted
coils, but because of cracking during drying and/or firing, they have a
high failure rate. Extruding the coils puts an end to cracking problems, as well as speeding up the job considerably.
The
main body of this pottery bucket is a straightforward thrown cylinder;
the extruded rim and handle that give it a unique look. | 
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Rope-top bucket, 8 inches in height, with ceramic and brass handle and extruded rim, multicolored slip-glaze exterior and gold manganese interior.
| 1. Lay a twisted rope extrusion on the top edge
of the pot. | 2. When the rim is leather hard, punch two holes for
the handle bail using a
piece of quarter-inch tubing. | 3. Make a clay handle from
a short piece of the same twisted extrusion by rolling
it over a “handle roller”. | 4. Make a handle roller by gluing short pieces of wood trim (quarter round and cove molding) to a board. |
To make the bucket, use around 3 and a half pounds of clay to throw a 6-inch diameter cylinder that’s about 7 inches high. When finished, do not cut the pot off of the bat since you’ll need to return it to the wheel later to attach the rim. Once the form has set up to leather-hard, lay a twisted rope extrusion on the top edge of the pot (figure 1), starting with one end and working to the other. Use a cheese cutter or fettling knife to cut the extrusion to exact length at an angle along the twisted lines in the extrusion. This will provide more surface area to achieve a good tight joint.
Attach the rim to the pot, inside and outside by gently pushing clay down and into the bucket body, then smooth and blend the join by slowly rotating the wheel and gently “throwing” the juncture. Pinch and extend the rim at opposite sides of the bucket to form two lugs for the handle. Add decorative pellets or coils on either side of these lugs, then cut the bucket from the bat and cover it to allow the moisture level to even out. When the rim is leather hard, punch two holes for the handle bail using a piece of quarter-inch tubing (figure 2).
Make a clay handle from a short piece of the same twisted extrusion by rolling it over a “handle roller” (figure 3). You can make a handle roller by gluing short pieces of wood trim (quarter round and cove molding) to a board (figure 4). Just before the handle reaches leather hard, make a hole with a metal rod through the length of it. Tip: When making the hole in the handle, push the rod in about one inch on one end, then do the same from the other end. Alternate from each end until you reach the middle.
After firing, insert a 14-inch long brass rod and center it. (Brazing rod works well.) Bend the rod 90 degrees at each end of the handle with your hands. Then, at 3/8 inch from the end of the rod, use pliers to bend the rod outward at a 90 degree angle. Thread each end of the rod with a 6-32 metal cutting die. Threaded brass balls from a lamp parts supply company secure the handle to the bucket.
David Hendley has been
enthusiastically extruding since building his first clay extruder in
1975. Check out www.farmpots.com, to
contact David, see more pots or for information about his DVD video
series “EXTRUDE IT! Getting the Most From Your Clay Extruder.”
|  | The same three-lobe die (shown here in four sizes) is used to make the rim and the handle. These dies were all made from small pieces of Plexiglas that are inserted in the extruder the same way the credit card dies are (see Credit to Die For). Rope dies are easy to make—simply drill three holes, then use a jeweler’s saw to connect the holes and cut away the center part of the die. While the extruded coil does not look very interesting, once twisted, it has the appearance of three coils twisted together. To achieve this look, twist the top end first, flip the coil over, twist the other end, then twist the middle. You’ll need a 24 inch extrusion to fit a 6-inch pot. Lay the twisted extrusion in a circle on the bat around the base of your pot, then attach it once it has set up a bit.
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