Project Materials and Supplies
- Hard Goldie Bronze™ clay
- Two tiny magnets – I used 2 mm in diameter
- Bronze wire 1.6 mm/14 gauge (be sure the wire is made from a true bronze copper/tin alloy)
TOOLS, SUPPLIES AND EQUIPMENT:
- Basic Metal Clay Set-Up
- Plastic egg that can be separated into two halves
- Small teardrop shaped clay cutter
- Hand drill with a 6 mm diameter / #51 drill bit (same diameter as the wire)
- Stainless steel firing container
- Activated coconut shell carbon
- Steel bristle wire brush
- Epoxy glue
Prepare the clay. Reconstitute the clay by mixing with water according to the manufacturer’s directions . Then wrap the reconstituted clay in a sheet of plastic wrap and wait for an hour to allow the moisture to absorb evenly .
Cover the Egg and Make the Cut outs. Separate the halves of the egg into two domes . Unwrap the clay and roll it to a thickness of 5 cards (1.25 mm) . Wrap the clay around the first dome and cut off the excess clay with a sharp knife . Smooth any overlap- ping clay with your fingers. Use a little water if needed . While the clay is still moist make rows of evenly spaced cut-outs all around the dome as desired with a small teardrop cutter . Leave the first dome to dry and make the second one. Once both domes are fully dry sand them smooth with sanding sponges.
Make the magnetic clasp. Prepare the magnetic clasp. If you are uncertain of the height of the magnets use playing cards or other thickness spacers to check it. Roll two little balls of clay and flatten them to .25 mm (1 card) thicker than the height of the magnets, so for 2 mm thick magnets this will be 2.25 mm (9 cards). Centre each magnet on one of the discs of clay and press down with a plastic slat or snake roller to push the magnet level with the surface of the clay . Use a small round cutter or a sharp knife to trim away the excess clay, leaving at least a 1 mm rim of clay around each magnet . Leave to dry and then sand the edges smooth. Carefully remove the magnets and set aside.
Make the hinge. Roll out a clay snake 5 mm in diameter . Let the snake dry,then use a sharp craft knife or a scalpel to slice three 3 mm long segments from it, keeping the blade perpendicular to the snake . These segments will be the knuckles of the hinge.
Drill straight through the centre of each hinge knuckle . Thread the drilled knuckles onto the drill bit and check that they are perfectly aligned . Sand the knuckles if needed. Put the bronze wire through the hinge.
Attach the hinge. Hold the halves of the egg together and determine where you want to put the hinge. Hold the hinge (on the wire)against the egg and make pencil marks on both halves of the egg at the midpoint of the two out- er knuckles. Place a small ball of very smooth, moist clay (add some water if needed) at each pencil mark on only one dome of the egg . While the clay is still wet, press the entire hinge onto the egg to attach the two outer knuckles to that dome. It is important that the hinge is centred across where the domes meet . Leave to dry, then add more lump clay to reinforce the outer knuckle attachments. Use a damp brush to press clay into the crevices and blend the edges into the surrounding area , keeping the cen- tre knuckle clear of any moist clay as it will be attached to the other dome. Leave to dry again. Attach the middle knuckle to the other dome and reinforce with moist clay as before the hinge still held together on the wire. . Leave to dry thoroughly, then sand.
Attach the magnetic clasp. Once the hinge is completely dry, gently pull out the bronze wire and separate the two domes. Add a ball of moist clay inside the edge of one dome,placing it exactly opposite the centre of the hinge. Press one part of the magnetic clasp into the clay to attach it firmly with the recessed area for the magnet facing outward . Attach the other part of the clasp to the inside of the other dome, making sure both parts of the clasp are perfectly aligned.
Enclose the hinge wire. Trim the bronze wire to 2 mm shorter than the length of the hinge. Fill the outer part of the hole in one of the outer hinge knuckles with wet lump clay . Put both domes together and thread the bronze wire through the hinge from the other end  and fill the outer part of the opposite hinge with clay so both ends of the wire are embedded in clay. Make sure you don’t fill the holes with too much clay so the center knuckle can swing open freely. Leave to dry, then sand.
Fire the egg. Open the egg and place it face up on a 2 cm (3/4”) layer of activated carbon inside the firing pan . For the first firing phase, place the pan in a cold kiln and fire at a full ramp to 350°C (662°F) with a 1 hour 30 minute hold time. Carefully remove the hot container and place it on a heatproof surface . Add more carbon to cover the egg completely to a depth of 2 cm (3/4”) above the top edges of the clay. Return the pan to the kiln. Ramp at full speed to 820°C (1510°F) and hold for 2 hours. Turn off the kiln and leave the pan to cool to room temperature inside it. Then remove the egg from the carbon .
Finish the metal and glue in the magnets. Brush the egg inside and out with a steel wire bristle brush to make it shine! Use epoxy glue to glue the magnets into the center of the recessed areas in the clasp, making sure the sides of the magnet that face up are the ones that attract each magnetically. If necessary use a drill bit to widen the recesses for the magnets and get a good fit. Now your special egg is finished.