The “Oh!” cone ring by Angela Crispin appeared in our very first issue of Metal Clay Artist magazine. We were delighted to see Angela’s ring go on to win a Saul Bell Design Award.
It is only fitting to re-launch our project pages under the sponsorship of Mitsubishi Materials Trading Corporation with this elegant project.
Project and Images by Angela Crispin.
Editing by Margaret Schindel and Jeannette Froese LeBlanc
Project Materials and Supplies
Approx. 36 to 40g of fine silver metal clay (amount needed in order to roll clay out to size – actual ring weighs approx. 21g, CZ included)
Fine silver metal clay paste
3 or 4 mm cubic zirconia
Tools, Supplies and Equipment:
Basic metal clay tools (paint brush, slats/card, roller, sharp craft knife, etc.)
Linda Kaye-Moses Doming Plates, cone-shaped set
Paper, pencil, scissors
Set of ring gauges
Ruler or digital caliper
Flexible clay scraper
Dockyard 1.5mm u-shaped micro carving gouge or linoleum carving gouge
Round cutter matching inside diameter of a ring approx. 4-5 ring sizes larger than the desired finished size
Clay shaper (chiseled or round tip)
Nail files / salon boards and sandpaper in a range of grits (depending on chosen finish)
Fiber blanket (for firing)
Nylon jaw pliers
Optional Materials, Tools and Equipment for Keum-Boo:
24k gold keum-boo foil (5x 8 cm, or enough smaller pieces to cover the inside of the ring)
Ultralite Beehive Kiln
Red brass insert with center depression for Ultralite kiln
Cross-lock tweezers with fiber grip handles
Protective, flexible gloves that fit well (e.g., leather gardening gloves)
STEP 1: Use a pencil, paper and scissors to draw and cut out a flat pattern of the cone. The easiest way to do this without using math is to start by cutting a circle with a radius equal to the height of the cone. The largest cone has a height of 4 cm, so you will want to open your compass to 4 cm (approx. 1.5”) and draw out an 8 cm (approx. 3”) circle, making sure to clearly mark the center. Center the paper circle on the tip of the desired cone on the doming plate. Holding one side against the dome, wrap the paper circle snugly around the cone until the sides meet. Fold down the excess paper to both sides of the joining point to mark where the seam will be. Open the pattern and trim off the wedge of excess paper, leaving a margin of 5 mm (3/16”) on one side of the folded seam line (Fig. 1) so that you will be able to overlap the cut edges of the pattern in Step 2 when you make your 3D paper model.
Repeat to make a second paper pattern that you will use as a flat template for cutting the clay.
STEP 2: Create a 3D paper model of the ring. This 3D paper model will let you check the placement of the finger holes on paper before cutting out the fresh clay. Later on it also will help you check both the placement and size of the finger holes on the dried metal clay cone. Make sure the cone size you’ve chosen is appropriate to the size of the finger holes you will need. Make sure that there will be enough space to maintain at least 3/16” of solid metal clay on all sides of each hole for strength. Take one of the paper patterns and tape the seam closed, overlapping the edges by the 5 mm (3/16”) margin you left on one side and creating a cone-shaped model. Flatten the cone by folding this paper model in half with the taped seam on one edge. Briefly fold it in half again just to mark the centerline and then re-open the last fold.
Now you need to add the finger holes. The diameter of these holes should be equal to the inside diameter of a ring gauge that is 4-5 sizes larger than your desired final ring size (in order to account for clay shrinkage and the slant of the cone). Use a ruler or caliper to measure the inside diameter of the ring gauge, then use the compass to draw a finger hole centered horizontally on the paper template and with the outer edge of the hole 1 cm (3/8”) from the tip of the cone. Fold the paper template again along the center crease you marked previously. Now you have 1/4 of a cone with a half-circle (Fig. 2). Cut out the half circle and unfold the 3D model. There should be two evenly spaced full circles on your model with the taped seam to one side.
Depending on your enlarged ring size, the two finger holes should be spaced 7-9 mm (1/4” to 3/8”) apart at the tip of the cone. You need to leave enough metal clay between the holes – ideally at least 5mm (a bit more than 3/16”) – to ensure that the pointed tip of the ring will be strong (Fig. 3). Also test-fit your 3D paper model on the cone-shaped doming plate to make sure it fits correctly (Fig. 4).
STEP 3: Create the clay cone. Roll out the clay to approximately 1.9 mm (6-7 playing cards) thick. Texture the clay slab if you wish. Place the flat paper template (not the 3D model) on the clay slab and cut around it, using a sharp knife or a flexible clay scraper (Fig. 5). Note: If you choose to texture the exterior of the ring then
trim off the 5 mm overlap margin, since you will be making a straight butt joint instead of an overlapping beveled joint.
Lightly oil the doming plate cone and place the cut slab of clay on it, being careful to center the point of the v-shaped cutout at the tip of the cone. Wrap the clay around the dome and, if you did not texture the clay, press gently to make a light impression line where the ends overlap. To create a strong beveled joint, use a palette knife or tissue blade to trim the edge of the clay underneath the overlap at an angle, beveling it from the joining line to the edge (Fig. 6). Beveling this edge prevents excess thickness at the joint and minimizes the amount of sanding that will be required. Note: If you chose to make a textured exterior (and trimmed off the 5 mm margin for an overlap), you will simply be butting the straight edges together to make a butt joint.
For either type of joint wet both straight edges of the clay and add a little silver clay paste (Fig. 7). For a beveled joint overlap the top layer and press gently to push out any air between the layers, being careful not to make any dents or nail marks. For a butt joint press the edges together along the seam, being careful not to thin the clay by pressing too hard. Use a moistened clay shaper to smooth the clay and mend the joint, checking to make sure there are no gaps in the seam. Smooth the surface of the joint with a moistened finger (Fig. 8).
STEP 4: Cut out the finger holes. As in the 3D paper model, the finger holes must be cut out on both sides of the joint and placed at an equal distance from each other. While the clay cone is still wet, make a small mark about 1 cm down from the tip of the cone to indicate the closest edge of the finger holes, using your paper 3D model as a visual guide. Using a round cutter as close as possible (but not larger than) the diameter of the circles you cut in the paper pattern in Step 2, cut a finger hole in the clay at the marked height (approx. 1 cm from the tip of the cone) (Fig. 9). Rock the cutter to one side and then the other to make the round cut go all the way through the clay, touching the cone around the entire circumference of the circle (Fig. 10). Carefully remove the excess clay from inside the circle with a needle tool (Fig. 11). Repeat on the other side of the ring, making sure the second finger hole is aligned with the first one.
STEP 5: Dry and sand the ring. Carefully dry the clay with a heat source. I used a heat gun set on “low” and heated the clay at short intervals, making sure not to get too close to the plastic doming plate to avoid melting it (Fig. 12). Once the outer layer is dry and firm, remove the ring from the doming plate and dry the inside. To check whether the ring is dry, place it on its side on a piece of glass or mirror to make sure there is no condensation underneath.
When the ring is completely dry carefully sand the joint and the rest of the ring, inside and out as needed. The top edge can be sanded flat or beveled inward at an angle (Fig. 13). Place each of the finger holes on a ring mandrel, one at a time, to check that they match the enlarged ring size. Also check the placement and size of the holes by covering the outside of the ring with the 3D paper model. If the paper holes are slightly bigger than the ones in the ring, trace the paper openings on the clay with a pencil so you know how far to sand in order to enlarge the holes. You may find that you need to sand the upper portion of each ring hole a bit more to compensate for the angled sides of the cone. Do this carefully with fine sandpaper wrapped around a small tube or tool handle to keep the holes round and to avoid making any marks on the surface.
STEP 6: Set the CZ stone and add desired surface texture / decorations. With the ring upside down, center the tip of a 1.5 mm round Dockyard micro-carving tool or a small linoleum carving tool on the tip of the cone. Keeping the tip centered and at an angle (Fig. 14), rotate it in a full circle to carve a small cone-shaped recess the same size as your CZ stone. Drill a small hole to accommodate the pointed tip of the CZ. Apply a little paste around the sides of the hole and “glue” the CZ in place. Make sure that the edges (girdle) of the stone are recessed below the surface of the clay so that the stone will be captured securely by the clay when it shrinks. Clean the surface of the stone thoroughly to remove any clay dust. (Editor’s note: We recommend doing this with a cotton swab dipped in isopropyl alcohol AKA rubbing alcohol.)
If you wish, you can also use a triangular file to carve parallel lines around all or part of the top edge of the ring to contrast with the mirror finish (Fig. 15). Add any surface decorations you would like. You can cross-hatch the outer surface of the ring with a coarse nail file (Fig. 16), carve out lines and designs, make decorative holes, etc.
STEP 7: Fire the ring and reshape if necessary. Fill the inside of the ring loosely with a piece of fiber blanket to support the cone during firing, then place it upside down on a piece of fiber blanket. Fire the ring to 900°C (1650°F) and hold for 2 hours. Allow to cool, then check for any slight warping and make adjustments, if needed, with nylon jaw pliers or a wooden mallet and a ring mandrel.
STEP 8 (Optional): Apply gold foil to the inside using the keum-boo method, if desired. To apply gold foil inside the ring comfortably using the keum-boo method, place the domed red brass insert with the concave center depression on an Ultralite beehive kiln. Using tweezers, place the clean ring into the concave depression at an angle with the wide, open end slanting downward. Allow the ring to heat up until the kiln reaches its maximum temperature. Meanwhile, put on the protective gloves.
Use cross-lock tweezers in one hand to hold the ring in position. Use another pair of tweezers with the other hand to apply large pieces of 24k keum-boo gold foil to the inside of the ring, burnishing with a burnisher from the center of the foil outward to remove any air as you go. The part of the ring that is against the brass insert will be the hottest area, so turn the ring as you apply the gold onto each area to make sure the silver is hot enough for the gold foil to bond to it. Continue until the whole inside of the ring is covered with gold foil. Remove it from the heat immediately and allow it to cool. Remove any excess bits of foil, if necessary.
Another great resource for Keum-Boo: (recommended by Margaret Schindel)
“The Definitive Book On Adding 24k Gold Keum-Boo Accents to Metal Clay
Renowned metal clay master artist and teacher Celie Fago is the foremost authority on keum-boo, the ancient Korean technique for permanently bonding 24k gold foil to silver using a combination of heat and pressure. If you have any interest in adding gold accents to your silver metal clay jewelry, sculptures and other objets d’art, her book Keum-Boo on Silver is required reading.”
STEP 9: Finish the ring as desired. Polish the ring to your preferred matte or mirror finish. The ring in this project was mirror finished on the top edge and brass brushed and lightly polished on the outside to bring out the cross-hatched surface texture.
Variations: This cone shape allows for many variations. The wide opening can have a silver mesh added at mid-height for beading, bead strands or fibers, or it can be filled with resin. If you close the top (making the ring hollow) the top slab can be textured and set with a stone or it can be an insert of another contrasting material such as copper clay, bronze clay, wood, ceramics or Faux Bone™ for a different look.