Technique

ALL LEVELS | METAL CLAY

BRONZE & COPPER CLAY

inspire innovative by Catherine Davies Paetz

To check out a sampler of what all five clay inlay techniques look like, turn to page 75.

www.ArtJewelryMag.com

he recent arrivals of bronze clay and copper clay on the metal clay scene have introduced new colors to the metal clay artisan's palette. Not only are these clays visually striking in their own right, but they also offer endless possibilities for making dynamic designs when combined. I've been experimenting with various processes that inlay bronze and copper metal clays and have achieved beautiful results.

Here are five techniques I've developed for making copper and bronze metal clay inlay designs. Look for tips and troubleshooting information on drying and firing along the way. As you explore these techniques, you'll probably come up with a few more ideas on how to marry these warm-hued metal clays.

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Results will vary

Bronze metal clay and copper metal clay are new materials that artists are learning more about every day. My primer will get you started on combining these materials, but expect varying results depending on whether you inlay the bronze into the copper or vice versa.

Keep an open mind as you experiment. These clays have a reasonable price point, so making a test of your inlay design before you finalize a piece is an economical option.

NOTE: I used BRONZclay and COPPRclay for my experiments and projects. Firing schedules vary between brands, so if you use a different brand, follow that manufacturer's instructions for working with the clay and for drying and firing your pieces.

Thickness guide

The base layer of clay for your inlay design should be at least 5 playing cards thick so that it can accept an impression that's 2-3 cards thick. Maintaining the base layer at a thickness of 5 cards preserves the integrity of the piece, which will become thinner as you remove excess clay to refine the inlay layer.

Prevent warping

A mug warmer or dehydrator works best for drying the clay. Flat pieces must be turned often in order to prevent them from warping. To minimize warping, watch the piece carefully, turning it approximately every 60 seconds or more often if the edges begin to curl.

NOTE: Some warping can be corrected during the inlay step, when you'll wet the impressions in the base layer before adding the inlay clay.

Surface

To achieve a level surface, inlay bronze into copper with approximately equal amounts of each of the clays visible. Allow the piece to dry completely and then sand the surface. After sanding, fill any sunken inlaid areas with clay.

Because the clay shrinks as it dries, I like to leave some inlay clay above the surface of the base layer's impressions. Allow the piece to dry completely, then fire it according to the manufacturer's instructions. Clay that is inlaid into thin lines might sink slightly during firing.

NOTE: After firing, you can sand or grind an uneven surface level using sanding paper or sanding disks in a flex shaft. However, this might leave marks in the copper, which is softer than bronze.

Technique 1: Stamps

Roll out the clay . On a flexible Teflon sheet, use an oiled acrylic roller to roll out your bronze or copper clay to make a base layer of clay that's 5 or 6 playing cards thick. Apply one or two drops of olive oil to the surface of the base layer where you will stamp your design.

NOTE: Stamps with wide cuts rather than very thin cuts work best for this process.

Impress your design. Using even pressure, impress the stamp into the base layer 2-3 cards deep. Place the stamped clay on a mug warmer, and take steps to minimize warping. The stamped layer [1] must be completely dry (see the "Metal Clay Dryness" chart, opposite) before you add the contrasting inlay clay. (See "Inlay Contrasting Clay," page 72.)

Technique 2: Carved eraser or photopolymer texture plate

Roll out the clay and impress your design. On a flexible Teflon sheet, use an oiled acrylic roller to roll out a base layer of clay that's 5 or 6 playing cards thick. Set the base layer aside.

Remove 2 or 3 cards from each stack of playing cards. Compensate for the thickness of the eraser or plate by raising the remaining stacks of cards to the same height as your eraser or plate. Position your eraser or plate texture-side up between the stacks of cards.

Lightly oil the surface of the clay, and roll the oiled side over the eraser or plate to impress your design [1]. Dry the impressed clay completely, taking steps to minimize warping. (See "Inlay Contrasting Clay," page 72.)

materials

COPPRclay BRONZclay nEil toolboxes, page 88

Metal clcy Bronze clay additional tools & supplies

Stamps

Cardstock or plastic sheet for cutouts

Linoleum cutter (V or U shape), plastic eraser (optional)

Chasing hammer

Steel block

Cosmetic sponges

Copper tongs

Baldwin's Patina

See Suppl ers, page 93 See Safety Basics, page 89

Videos & Basics

Check out these bonus tutorials for fundamental techniques used in this project:

• Rolling metal clay

• Tumble-polishing

Basics, page 87 Videos, www.artjewelrymag. com/videos

Metal Clay Dryness

Wet

A lot of moisture; very pliable

Semi-dry

Some moisture; firm, holds its shape

Mostly dry

Nearly devoid of moisture; rigid

Completely dry

No moisture; can be fired

Make cutouts. Draw shapes on heavy cardstock or plastic sheet, then cut out the shapes with a craft knife or scissors.

Roll out clay and place the cutouts. On a flexible Teflon sheet, use an oiled acrylic roller to roll out a base layer of clay that's 5 or 6 cards thick. Lightly oil the surface of the clay where you'll be placing your cutouts. Position the cutouts on the clay.

Impress the design. Roll an acrylic roller over the cutouts, pressing them into the clay [1]. Using the tip of a craft knife or your tissue blade, carefully remove the cutouts from the clay. Dry the impressed clay completely, taking steps to minimize warping. (See "Inlay Contrasting Clay," page 72.)

Techniques 1,2, and 3:

Inlay contrasting clay

Prepare the inlay clay. Roll out the contrasting clay to a thickness equal to or slightly thicker than the depth of the impression in your dried base layer (2-3 cards thick).

Prepare the base layer. Using a paintbrush and distilled water, thoroughly wet the impressions in the completely dry base layer [1].

NOTE: If you add too much water, it will pool in the impressions, preventing the inlay layer from adhering to the base layer. Use a lint-free paper towel to wick excess water from the impressions.

Add inlay clay to a flat base layer.

Lay the inlay clay over the base layer. To remove any trapped air, use your fingers to lightly press the inlay clay against the base layer. Then use a lightly oiled roller to roll over the inlay clay, covering the entire base layer and filling the impressions.

NOTE: Air might become trapped in the inlay clay during the rolling step. If you detect any bubbles, use a needle tool to prick them, and then seal the hole by pressing it with your finger.

Remove excess inlay clay. Use either your fingers or a craft knife to remove excess inlay clay from the sides of the base layer [21. Then allow the piece to dry completely.

Add inlay clay to a curved or shaped base layer. After you've brushed the impressions in a curved base layer with distilled water, use your fingers to press the inlay clay into the impressions of the base layer [3].

NOTE: Adding the distilled water can soften curved or shaped forms, so you might want to support curved base layers on an armature when you impress the inlay clay.

Remove excess inlay clay. Using your fingers or a craft knife, remove excess inlay clay. Allow the piece to dry completely.

Spot-fill depressions. Inspect your dry, inlaid piece for any significant depressions in the inlay area. Wet these areas with distilled water, and use your fingers to spot-fill them with inlay clay. Allow the piece to dry completely.

online extra

For more about the development of bronze clay, including what it's like to work with, check out "Now Entering the Bronze Age" (July 2008). Subscribers, if you don't have that issue handy, you can download the article free at www.artjewelry mag.com/onlineartides. All readers can visit the same link to get Mardel Rien's in-depth look at BRONZclay firing procedures, including detailed firing charts and schedules.

It's not necessary to have separate sets of tools for bronze and copper clays when you're using these clays together to make inlay pieces. Running a lightly oiled hand over the roller to remove crumbs of clay between uses will minimize the chance of introducing bits of clay where you don't want them.

NOTE: It's a good idea to keep a set of tools for silver metal clay separate from your tools for bronze and copper clay to prevent cross contamination.

Prepare the base layer. On a flexible Teflon sheet, use an oiled acrylic roller to roll a base layer of clay that's 5 or 6 cards thick. Dry it to a semi-dry state, taking steps to minimize warping.

Carve the base layer. Using a linoleum cutter, carve a design into the clay [1].

& SAFETY TIP: Do not cut toward your body or your other hand.

NOTE: Some people like to carve clay when it's in a semi-dry state; others prefer to carve clay when it's completely dry. Experiment with carving in various states of dryness to determine your preference.

Allow the clay to dry completely [2], taking steps to minimize warping.

Add contrasting inlay clay. Using your paintbrush and distilled water, thoroughly wet the carved areas of the base layer. Using a small spatula or palette knife, generously "spackle" contrasting inlay clay into the recesses [3]. Allow the piece to dry completely.

If you detect any depressions in the dried inlay areas, wet these areas and use the spatula to spot-fill with inlay clay. Allow the piece to dry completely.

TIP: When the carving pattern curves, rotate the clay instead of the cutter.

Prepare the clay. On a flexible Teflon sheet, use an oiled acrylic roller to roll a base layer of clay that's 5 or 6 cards thick. Lightly oil the areas of the base layer where you will impress the wire.

into the clay [1]. Remove the wire and allow the clay to dry completely.

Prepare the base layer. Use a paintbrush to wet the impression in the base layer with distilled water.

Prepare and impress the inlay clay. Use an acrylic sheet to roll thin cylinders of the contrasting inlay clay. Press the cylinders into the wet impressions [2], allowing the inlay clay to protrude slightly above the surface of the base layer; this compensates for the shrinkage of the inlay clay as it dries. Allow the piece to dry completely.

Prepare the wire. Bend 18-gauge (1.0 mm) or 20-gauge (0.8 mm) wire into your desired shapes. Use a chasing hammer and a steel block to flatten the wire; flattened wire creates impressions with wider lines than nonhammered wire.

Prepare the clay. On a flexible Teflon sheet, use an oiled acrylic roller to roll a base layer of clay that's 5 or 6 cards thick. Lightly oil the areas of the base layer where you will impress the wire.

Impress the wire. Position the wire on the clay. Use your fingers or a flat piece of lightly oiled acrylic sheet to press the wire

NOTE: Curved pieces are especially vulnerable to overly aggressive sanding, because it's easy to remove too much material when sanding a rounded surface.

Revealing the inlay design

Generally, a good way to remove excess inlay clay before you fire your piece is to use a combination of dry sanding and damp sponging.

Sand the surface of your piece. Make sure your piece is completely dry, and then use a 120-grit emery board or sanding stick to remove excess inlay clay [1]. Remove just a little material at a time. When you begin to reveal the base layer of clay, progress to finer grits or switch to sponges.

NOTE: Curved pieces are especially vulnerable to overly aggressive sanding, because it's easy to remove too much material when sanding a rounded surface.

Sponge the surface. Moisten a cosmetic sponge with distilled water, and lightly wash away the excess clay [2]. Be sure to support curved or formed pieces, which will soften from the water. Sponging creates less sanding dust than emery boards and gives the clay a smooth surface. Allow the piece to dry completely.

Firing

NOTE: Firing bronze clay or copper clay requires a kiln, kiln stilts, and a lidded stainless steel container filled with activated carbon. Follow the firing schedule for bronze clay. When you're firing pieces that contain both copper clay and bronze clay, you must use the firing schedule for bronze metal clay. If you fire the pieces at the higher temperature that is recommended for firing copper metal clay, the bronze will blister.

Load the stainless steel container. Fill the stainless steel container about one-third full, or at least 1 in. (25.5 mm) deep, with the activated carbon. Place your pieces vertically or horizontally in the carbon, keeping them about Vi in. (13 mm) apart and away from the sides of the container [3]. Cover the pieces with about 1 in. (25.5 mm) of carbon and put the lid on the container. Set the container on the kiln stilts in the kiln, being careful not to push the kiln's thermocouple into the muffle . Close the kiln door.

General firing-schedule guidelines. The firing schedule depends on the thickness of your pieces. The thicker your pieces, the slower the ramp schedule.

Ramp the kiln at 250°F (121°C) per hour to 1550°F (843°C), and hold for 3 hours.

Pieces thicker than Vs in. (3 mm):

Ramp the kiln at 125°F (51.6°C) per hour to 1550°F (843°C), and hold for 3 hours.

NOTE: Running the longer program for thinner pieces will not harm them.

Allow the pieces to cool. Allow the kiln to reach room temperature, and remove the pan to a heat-proof surface.

Use tongs to remove the pieces from the pan.

Check the pieces for cracks. Carefully inspect each piece. Any very fine lines online extra v v

To learn kiln terminology, check out "Anatomy of a Kiln" at www.artjewelrymag.com/ reference. The article is an excerpt from "The Care & Feeding of Your Kiln" (March 2009).

Plastic cutouts

Carved eraser

related projects

For more projects like this, check out "Water Works" (September 2006) and "Kissed by the Sun" (May 2006). If you don't have those issues, you can buy PDFs of the individual projects at WWW.

artjewelrymag.com/projects.

between the two clays may become less noticeable after tumble-polishing.

If you find significant gaps or cracks, fill them with fresh clay, dry the piece completely, and refire it at the shorter firing schedule.

Finishing

You can finish your inlay pieces with a brass brush and soapy water, or use a tumbler with steel shot and burnishing compound . The color contrast between the bronze and copper may not be very pronounced.

Apply a patina. To enhance the color contrast, use Baldwin's Patina according to the manufacturer's instructions. The patina will darken the copper but not the bronze.

Use a cotton swab to apply the patina to the surface of the piece. Then, rinse the piece with water and repeat until you achieve the desired color [4]. Then give the piece a final water rinse and dry it.

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