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How to Make Custom Hardwood Throwing Ribs for Your Pottery

Posted By Robert Balaban On April 28, 2010 @ 8:33 am In Clay Tools,Daily,Features,Making Clay Tools,Pottery Making Illustrated,Throwing Tools | 20 Comments

Have you ever been using a store-bought throwing rib and thought, “if only this rib was shaped like this…or…like that?” Most of us make do with the standard shapes of ribs in our throwing because the more specialized fancy ribs can get expensive or it just seems daunting to make our own. But, it is surprisingly easy to make your own custom ribs if you have some basic woodworking tools. And it can be pretty darn cheap if you have access to a wood worker’s scrap pile! Making your own customized ribs is not only a way to help facilitate your personal aesthetic touches, but, as Robert Balaban puts it, it “permits creativity to extend from the clay to the tools.” In today’s post, Robert shares his system for creating custom hardwood throwing ribs.  – Jennifer Harnetty, editor.

I’ve
always looked for ways to improve the quality of my art by fashioning
customized hand tools to facilitate the shaping my vessels. In these efforts,
I’ve developed a simple system of constructing hardwood ribs for a variety of
throwing purposes. This permits creativity to extend from the clay to the
tools. Many studio visitors and students have enjoyed using or creating these
tools and often leave the shop with a couple of customized ribs that make a
lasting impression on their craft. Custom hardwood ribs are easy to create, and
can be constructed in under one hour using skills that any potter can master.

Choosing the Best Wood

I’ve experimented with several types of
wood, from the most exotic (mpingo, purple heart, bocote, and
cocobolo), to mahogany and cherry, coming my way from a woodworker’s
scrap pile or from my own backyard. Maple, osage orange, black locust,
and even mountain laurel also work well. Red or white oak and poplar
are hard to use because they swell when wet and typically have large
growth rings that make a consistent edge difficult to achieve. Usually
any dense hardwood with resistance to water damage is appropriate. The
best, cheapest, and locally available wood (not from the fragile rain
forest) is American black cherry. The 5/16-inch thick stock is a good
starting material. Slightly thicker or thinner material can be used
depending on taste or task. If you buy wood, a couple of dollars of
5/16-inch wood can generate 10 to 20 ribs.



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Fig.1 Trim and attach the paper using double-sided tape. Cut out the rib leaving the tracing in place.

Fig.1 Trim and attach the paper using double-sided tape. Cut out the rib leaving the tracing in place.

Generating and Transferring Designs

Creating different ribs for novel shapes or tasks can be done using paper,  pencil,
and a French curve or other guide or pattern to help generate that
perfect curve or angle. You can also use computer drawing programs,
draw free hand or simply copy more familiar rib designs and modify them
to your needs or hands. I use a versatile French curve-style rib for
working on the inside of vases and other forms. The first step in
making this type of rib is to trace the template onto paper and secure
it to the piece of wood.

Making the Rib

The next step is to cut the wood, using a hand coping saw, scroll saw or band saw (figure 1) and leaving the traced line on the rib to permit fine tuning later.

Caution: When
working with power tools, read and follow all manufacturer safety
materials before use. Dust from some woods can be toxic or contain
allergens, therefore always work in a clean ventilated area with a
respirator or dust mask for the cutting and sanding stages.

Fig.2 Fine tune the finger groove at the small end and customize the overall shape using a spindle sander.

Fig.2 Fine tune the finger groove at the small end and customize the overall shape using a spindle sander.

With the completed rough cut shape, the
next steps are to finish the outline, taper the edge that will guide
the clay, and generate a true sharp edge to create a smooth finish on
the clay. The best tool to quickly accomplish all of these tasks is an
oscillating spindle sander. It’s a rotating cylinder of sandpaper that
moves up and down with interchangeable spindles of different diameters
that can be used to refine the various curves of your rib 
(figure 2). Alternatively, different size dowels with sandpaper wrapped around them also work, they’re just slower.

Next, true the shape of the rib blank by
sanding the rough edges using an 80-grit sandpaper. If you make a rib
with an arc that’s smaller than the smallest spindle available, or have
a square or triangle in the rib, these will need to be hand filed. For
the French curve rib, make a groove using a 5/8-inch
spindle to fit your index finger at the small end (see figure 2) and to
allow for leverage on the clay when pushing the larger belly end to the
inside of a pot. This customizes the rib to your throwing style as well
as your specific grip.

Now create a tapered edge to guide the
clay using the largest diameter spindle or a sanding block. This is
done by approaching the spindle at an angle with the rib blank and then
sanding it down to a 45° angle. Taper all outside edges of the French
curve to accommodate all your throwing needs. The small circle on the
end of the rib is also a very useful part, taper all edges here as
well. Finish the taper on the larger structures, then make more severe
tapers around any sharp features to help guide the clay through tight
areas. Then round the all of the remaining edges for a better feel 
(figures 3 and 4).

Fig.3 Sandpaper used alone, on a sanding block, or wrapped around a dowel for tight curves also works well.

Fig.3 Sandpaper used alone, on a sanding block, or wrapped around a dowel for tight curves also works well.

Fig.4 Taper the edge of the rib by angling the piece as it is brought to the sander and move with long strokes.

Fig.4 Taper the edge of the rib by angling the piece as it is brought to the sander and move with long strokes.

To customize the rib even further, add finger holes to improve grip and leverage. Hold the rib as you would while throwing and mark the area around your fingers. (Clamp the rib flat to a backing board to drill the finger holes). The back up board ensures that the drill bit will not split out the back side of the rib (figure 5). Mark an outline of your finger’s grasp with a pencil then taper the hole for a customized fit. Return to the spindle sander and insert the 1/2-inch sanding spindle into the hole. Sand the inside of the hole and then angle the rib while it is on the spindle to generate an oblong tapered hole that matches the angle of your fingers (figure 6).

Finally, sand the rib by hand using 200 then 400 grit sandpaper—only a
couple of minutes with each grit is necessary. A good trick is to then
wet the wood and dry it. This causes any wood grain that might rise
with water to do so and then you can sand this off for a very smooth
and resilient surface.

Fig.5 Drill 5/8-inch finger holes where your fingers naturally grasp.

Fig.5 Drill 5/8-inch finger holes where your fingers naturally grasp.

Fig.6 Smooth each hole then tilt the rib to mimic the marks made by your fingers.

Fig.6 Smooth each hole then tilt the rib to mimic the marks made by your fingers.

A finished rib with customized curves and finger holes.

A finished rib with customized curves and finger holes.

Finishing Work

The finish you use can vary. Using bare, untreated ribs is fine if they are made with a strongly water resistant wood like teak. Alternately, different oils and several different waterproof varnishes can be used to seal the surface. I have found that the oil-based Minwax Clear Shield finish or marine varnish is very strong and the clay slips nicely along this surface. Follow the oil manufacturer’s directions on application and appropriate drying times. Finishes will still wear off and need to be reapplied.

Using these techniques, you can make a rib, try it out on the wheel the same day, make adjustments, finish/dry it overnight, and have it ready for the next day.

Robert Balaban is a functional potter and teaches classes in his studio. He not only creates ribs from dead trees found in the woods, but he also specializes in creating safe glazes from the natural products in his gold producing backyard in Maryland.

 


This article appeared in Pottery Making Illustrated magazine’s May/June 2010 issue. To get great content like this delivered right to your door, subscribe today!



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