Here's the tutorial I've been promising.
(It's kind of long.)
In order to do this project you need to have access to a metal studio. A lot of high schools and universities have these available. You might want to check out community access to these. I live in St. Paul and we have a community education program and you can pay a fee and get access to metal studios as well as woodshops, ceramics studios etc. Equipment Needed:
(Standard in Metal Studios)
-Centrifuge for lost wax casting
-2 Canisters for plaster mold Materials needed:
(Some of these are hard to find at craft stores like Michael's, so look at an art supply store instead.)
-Plastic Easter Egg
-Wax strips (specific for lost wax casting, these come in thin snakes about 6 inches long.)
-Metal wax carving tools (one tool looks like a small curved spatula the other looks like a large needle)
1. Use a strip/snake of wax to make a little ring of wax and place the egg on it so it is standing up. This little ring will become the base of the finished box, so it doesn't roll over.
2. Using the strips of wax, decorate the egg. I used little snakes of wax as the vine. I placed the snakes where I wanted them. Then I heated the needle tool in the alcohol burner and ran the hot point along the wax where it joined the egg. This basically glues the vines to the egg.
The leaves were made from working the wax like modeling clay to make little leaf shapes. I used the same technique as before to attach the leaves to the egg. Then I waited for the needle tool to cool and used the point to carve the veins of the leaves.
3. When decorating is complete, use a razor blade to cut through the decoration at the seam between the top and bottom of the egg. Then open egg so you have two halves.
4. This is where you use the plaster canister. It looks similar in size and shape to a tin can, except that both sides are open. It should be metal with a rubber lid. Place the can so the lid is on the bottom.
Remove the can and set aside. Leave the lid sitting this way for the next steps. (Do this for both canisters.)
5. On the lid of the canister, make a little hill of wax in the middle. (About 1 inch wide and 1/2 inch tall.) Do this to both lids.
In the middle of the mound make a post of wax using one of your strips. This post should be about 1/2 to 1 inch long.
6. Attach one side of the egg to the top of the post. Attach the post in the same way as the decoration by making a tool hot in the alcohol burner and melting the wax to the egg. After this step the wax and egg should resemble a wine glass. (Repeat this to the other egg on the other lid.)
7. CAREFULLY, attach the canister to the lid so that the wax piece is on the inside of the can. You should be able to look in from the top and see if your piece got damaged in this process. You may need to take the lid off again and fix any mistakes. **After the next step you will not see your piece until it is finished, so now is the time to fix any problems.**
8. Mix your plaster according to the directions on the package. It should be the consistency of a milk shake.
9. Carefully and slowly pour the plaster into the canister, covering the wax piece.
10. Put canister into vacuum pump and remove the air. This will get rid of air bubbles that are trapped in the plaster. **Remember that any air bubbles stuck to the wax will become part of your finished piece.** This is what happened to my egg when I was rushing this step. Let the plaster dry.
11. Remove the lid from the canister. Part of the wax might break off at this point, but it is okay.
Place in a kiln with wax facing down and turn on kiln. (I can't remember the temperature necessary for this step, but whoever runs the metal studio should know.) **This step melts out all of the wax and the plastic, leaving a space in the plaster.**
12. Place the plaster canister into the casting centrifuge, with the hole facing the center of the centrifuge.
13. Put the pieces of silver into the tray and heat them with a blowtorch.
14. This is the scary part! While the silver is still molten, push the switch to start spinning the centrifuge. It will seem like molten metal will fly everywhere, but if it is all set up properly it should just go straight into the mold.
15. Using tongs, put the canister into cold water. This will cause the plaster to break apart and dissolve leaving just the silver behind.
Fishing around in the water you will be able to find your silver piece.
16. Do steps 4-15 with both the top and bottom pieces. Then saw off the little pedestal that is left over from the casting. Sand and polish if necessary.
17. Put the top and bottom back together.