Copper with Silver Inlay
Art Clay Silver and Art Clay Copper were used for this pendant. I have not tried this technique with other varieties of copper and silver. If you’d like to try, you’ll need to do test firings, as firing schedules may need to be adjusted to suit the clays.
50 gm package Art Clay Copper
7 gm Art Clay Silver
14 Gauge wire
Additional tools and materials:
Needle nose or forming pliers
Delrin hammer and anvil
Tsukineko Fantastix Coloring Tool Brush Tip
Shape template - Fat rectangle
Straw or plastic stick
Form a length of 14 gauge wire into a pleasing shape using the appropriate pliers for your chosen pattern, shape and coil the wire. Hammer flat if needed. Alternatively, use a stamp or texture plate. If choosing a stamp, make sure your pattern is of one depth, all subtle shading and textures will be lost when the recesses are filled with silver.
Lightly lubricate a sheet of Teflon and roller, olive oil, Badger’s Balm or a commercial no-stick spray. Roll the wet copper clay on a sheet of Teflon to 2.25 mm or 9 cards thick.
Remove the 0.75 mm slat or 3 cards. Place the wire pattern on the wet clay, and press the wire into the clay using either a roller or your fingers. Do not press too hard. Carefully remove the wire pattern. Using the rounded end of a paint brush and/or ball burnishers, press dot patterns into the wet clay.
Cut the wet clay with the shape template using either an Exacto knife or a needle tool. The template used for this piece is called a “fat rectangle.” Dry the clay thoroughly, either air dry or in a dehydrator.
Finish the piece as needed. Use a Tsukineko Fantastix Coloring Tool Brush Tip to smooth out the sides and surface and then sand the completely dry clay to a smooth surface with polishing cloths. Blemishes in the surface of the copper could hold silver clay in the next step.
Once finished, lightly moisten the interior of the recesses with a wet brush. Using an Exacto knife, lightly scrap a portion of silver clay up on the Exacto and force it into the recesses. The Exacto knife has less give than a rubber shaper and more completely presses the clay into the recesses. Make sure you fill the recesses, do not leave any air pockets or gaps as you inlay the silver. Continue until the recesses are fully inlaid with silver. Don’t worry if you get some silver on your copper, you will sand off the excess silver after dry.
Try to keep your silver clay uncontaminated by copper clay. If you do contaminate your silver, put the contaminated clay aside in a separate area. Do not discard this clay, you can use it to make alloyed silver and copper clays similar to shaduko or shibuichi.
Dry the copper/silver piece thoroughly. Sand the excess silver from the completely dry piece until the silver pattern is revealed. If there are any areas that need more silver clay, moisten and add more clay. Make sure the copper/silver piece is nicely finished.
To add a bail to the pendant, roll a length of wet copper clay to form a snake. Roll wet clay with your finger, lightly moistening it with a damp brush as you roll. Form the bail around a straw or appropriate plastic form by coiling around the form 2 or 3 times. Dry the bail thoroughly.
Once the bail is completely dry, sand a flat surface on one section of the bail. Using water and some wet copper clay, add a bit of moistened wet clay between the top of the pendant and the flat surface of the bail. Press firmly together and adhere the bail to the top of the pendant. Allow to dry thoroughly.
Roll a short length of wet copper clay into a snake and add it to the back of the pendant starting at the bail. Try to mimic the coil pattern on the front of the pendant. Allow to dry thoroughly.
Drill a few recesses in graduated sizes on the back. Do not drill through the pendant. Fill these recesses with more silver. Dry thoroughly.
Sand and clean up the back. Check to make sure your piece is nicely finished without blemishes and fire.
To fire the pendant, place the piece on a 1" layer of coconut charcoal and fire to 900 degrees for 20 minutes. When cool enough, open the kiln, add another inch of charcoal over the now black piece. In a brick kiln, fire at a 1500 degree ramp to 1400 degrees and hold for two hours. In a fiber muffle, you may have to raise the temperature a bit to get the copper to sinter. However, do not raise the temperature too high, as the copper and silver will alloy. I find this generally happens around 1500 degrees. However, as all kilns are different, testing may be necessary.
Remove the piece from the charcoal. Since this is a low temperature for sintering copper, a second firing is occasionally necessary. To test for sintering, take a 30 grit 3M radial polishing disc and begin to polish the back. If your piece is still powdery and black, repatch the back and refire without the binder burnout phase. If you see a copper layer and then a black powdery layer, refire without the binder burnout phase. If your piece continues to polish up showing only copper, it is sintered. Continue to remove all of the oxidation on the surface with the polishing disc.
If there are any cracks or holes along the silver/copper inlay border, fill with more silver (or copper if appropriate) and refire at the sintering phase. Some cracks are so tiny that filling is almost impossible, so you may have to let a few go.
If there are no cracks, or once any cracks have been patched and refired, use 3M Polishing radial discs, Cratex or AdvantEdge polishing discs to polish the piece or tumble finish if desired.
If you wish to create more contrast between the silver and copper, use Baldwin’s patina to accentuate the contrast. A mirror finish does not take this patina well, so if you want to use it, slightly matt down the surface. Wet a cotton swap with Baldwin’s patina and rub it over the surface of the piece. Once the copper has been completely swabbed with the Baldwin’s, rinse it off under warm running water. Dry thoroughly.
Tips and Tricks:
Try a Fantastix! Tsukineko Fantastix Coloring Tool has a nice rough surface that is moistened and used as a wet sander. It nicely rounds out and cleans up edges. They are gentler than a sanding pad and also rehydrate the surface of the dry clay and move the clay around, so that you can fill small cracks and blemishes without adding more clay. Their greatest benefit, however, is keeping metal clay dust out of the work area. These will leave a slight texture on the clay. If this is not desired, use a smooth cosmetic sponge or polishing cloths to go over the surface after using the Fantastix.
My favorite place to find sanding materials is the beauty supply store. The sanding pads and sticks for nails are wonderful and generally less costly than the polishing pads sold by jewelry supply places.
Save all your mixed metal scraps from this project. If the scraps are more copper than silver, use it to inlay in silver. If the scraps are more silver than copper, use it to inlay in copper. You can actually get some subtle shading by using different percentages of copper and silver for inlay. Or just rehydrate the mix of clays and use it to make an entire piece.