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Large Hollow Bead
BY Barbara Becker Simon
Intermediate to advanced metal-based clay project.

In Lapidary Journal, August 2000, I showed one method for making a hollow bead. This was suitable for small, round forms, no bigger than 1-1/4" in diameter. Beyond that dimension and shape, the Precious Metal Clay (PMC) cannot support itself during later firing stages, when it is almost liquid.

The idea for this complex core came from my need to make larger hollow forms, and I developed this system through trial and error. The core is comprised of styrofoam and wax, designed to be used with PMC. The final coating of wax allows for the shrinkage factor of PMC.

You can easily adapt this method for use with PMC+ - simply make your last wax coat 1/16" thick.

For the hot, melted wax, use any kind of wax, including old candles or paraffin. Just make sure that it is carefully monitored as it melts in a double-boiler. Never leave the melting wax unattended. Heat it only to the melting point, never beyond, as it can ignite spontaneously.

STEP 1.
Cut a piece of the soft florist's foam with a razor blade or similar tool.

STEP 2.
Using the blade, your fingers and any tools you need to define your design, fashion a shape that is a bit smaller than the final form desired. You can use other materials for this initial core, but I like this soft foam because it is so easily formed and very inexpensive.

STEP 3.
To make the holes of the bead, use two 3" lengths of drinking straw. Insert 1 piece of straw about 3/4" deep into 1 side of the foam and the other in the opposite side. (I find this easier to do than trying to insert 1 long straw through the entire form. It invariably ends up crooked.) The straws will also act as handles. You can use smaller openings but this will hamper the removal of the fired paper clay. (You can also cover the entire form and cut holes later.)

STEP 4.
Using melted wax, paint a thin layer over the foam. This doesn't have to be thick, just enough to give the foam rigidity. If you are using another material that is already rigid, you can skip this step.

STEP 5.
Roll out a sheet of paper clay, 3 playing cards thick. If you are using a particularly thick layer of PMC, the thickness of the paper clay should increase.

STEP 6.
Cover the wax-coated form with this layer of paper clay. (I cut the paper clay into strips, piece it over the form, and smooth all seams.)

This will be enough to support the PMC during the firing and yet will not be too difficult to remove. The paper clay will not be altered in any way during firing.

(Make sure to clean up all traces of paper clay from your work surface. They look very similar to PMC and you don't want to get the materials confused.)

STEP 7.
Set this aside to harden.

It may take 24 hours because the paper clay must be bone dry.

STEP 9.
Let the wax layer cool.

STEP 10.
Be sure to apply a little olive oil to your hands and your tools to prevent the PMC from sticking. Roll out a sheet of PMC like you did with the paper clay. A stack of 2, 3, or 4 cards gives a nice depth, depending on how thick and heavy you want the end result. I have found that 2 cards' thickness results in a strong and lightweight piece. (If you want to impress or stamp a design into the surface, make a thick layer 4 cards high.)

STEP 11.
Cover your form with the sheet of PMC by piecing and thoroughly blending the seams as you go along. You can use water or PMC slip to aid the closing of the seams. Make sure to cover with a consistent depth, as thin spots may result in cracks.

STEP 12.
At this point, the decorative surface or texture is up to you. Have fun. Before I decorate I like to let my base coat dry completely, unless I am stamping. This way, any cracks resulting from drying can be “caulked” with more clay.

STEP 8.
When the paper clay layer is dry, take melted wax and apply it over the form to a depth of exactly 1/8".

To check the depth, stick a straight pin or a needle tool into the wax until it hits the hardened paper clay layer. Measure how much of the pin is below the surface.

(The wax can be brushed on or dipped. This step not only allows for shrinkage, but PMC should never be formed directly over paper clay. It doesn't stick well and the paper clay will absorb the moisture content from the PMC, making it difficult to manipulate.)

STEP 13.
Let it dry. Set up for firing. Make sure that the form is completely supported underneath with vermiculite or alumina hydrate. I use either a clay flowerpot saucer or a stainless steel ring to hold and contain my support material. Standard PMC fires at 1650°F for 2 hours.

STEP 14.
After firing, if the width of the bead hole allows it, you can pick out the fired paper clay with a dental tool. Usually, all it takes is just getting it started and the rest chips away fairly easily. Leaving it in does no harm and adds no appreciable weight.

STEP 15.
Finish the PMC to your liking. (The finished, polka-dot heart bead had a patina chemical applied, brass-brushed with soapy water, and then the high spots were burnished.)

PMC fish shown is another example using the hollow core technique.

Barbara Becker Simon is a jeweler, glass bead maker, and teacher. She is currently a Senior Instructor with the PMC Guild. Contact Barbara at www.bbsimon.com.

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