Craftsman of the Month
Cover of Rock&Gem V1N1 March-April 1971

Robert Waltke - June 2000 - Striking Cobra

The Basket

Use a sharp pencil and a straightedge to draw 10 lines 1/16 inch apart on a piece of cardboard. Make the lines 5 or 6 inches long.

Smear a very thin film of oil or grease on the cardboard.

Place a sheet of 24-gauge wax on this grid, and with a metal straightedge and a sharp blade (slightly heated), slice off 10 strips of wax.

Grasp the strips one at a time, and twist them until they resemble ropes.

Fold 1/8 inch of one rope back on itself. Lay this nub on a flat surface, and continue winding the long end of the rope around it. Add another piece when necessary.

With a small amount of molten wax on a hot spatula, carefully tack the coils together as you proceed. When the bottom of your basket is about 3/4 inch in diameter, raise the next coil up on top of the lower one, and angle it out slightly.

Continue this procedure until your basket is about 1-1/4 inches in diameter and about 1/2 inch high.

Cut four 1/8-inch-wide strips of 24-gauge wax about 1 inch long. Press one aligned vertically against the inside wall of the basket, starting about 1/4 inch from the center at the bottom. Tack it in place with some molten wax. Repeat with the other three strips, equidistantly spaced. These will act as internal sprues to ensure a complete casting.

Now add the remaining coils. Gradually angle them inward to complete the form of the basket. Use a headed nail to press the vertical sprues in place, and cut off the excess length. Use an extra coil or two to form the neck of the basket.

Form the cover of the basket the same way that you started the base. When the cover is about 3/4 inch in diameter, use your fingers to give it a dome shape, and then seal it to the side of the basket with a big drop of molten wax.

The Cobra

Carve the cobra from a block of hard wax approximately 1-3/4 inches long by 5/8 inch wide by 1/4 inch thick.

The bottom of the cobra is given a narrow dimension, and a donut of wax about 1/8 inch thick and 3/8 inch in diameter is formed 1/4 inch above its end.

The Retainer

Form a piece of 14-gauge wire wax into a loop that is just a fraction of an inch smaller than the donut formed at the base of the cobra.

Attach a 14-gauge tail to this ring, and bend it down at a 45-degree angle. This configuration may also be made from a sheet of 24-gauge wax.

Make a hole 1/8 inch in diameter in the side of the basket, just under the spot where the cover is attached to it. Make four more holes the same size in the bottom of the basket. This will prevent the investment core from breaking loose during the casting process. Refer to the diagram for spruing recommendations. Use your regular method for casting the pieces.

Assembly

Curve the tail of the retainer outward for easy assembly. Slip it over the head and hood of the cobra. Feed the end of the tail through the hole under the cover. The retaining ring should be well down in the basket.

Solder it in place, and cut off the excess.

Suggestions

Consider using tiny gemstones for the cobra's eyes. Mount your striking cobra on a small polished stone base. What kind of stone? Why, serpentine, of course!


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