Print PDF
Favorite
Email
Step 7Prepare the Plaster Casting for Molding
To get the plaster piece(s) ready to make your rubber mold with, you'll need to:
1) Shape and join the parts--for instance, my pig's feet came as two halves, so I cast two halves and then glued (with wood glue) the two plaster halves together. After glueing them together, I then used plaster sanding screen to shape the foot, getting rid of the excess where the two pieces didn't come together perfectly.
2) Seal it--since plaster is porous, you'll need to seal it with several coats of shellac or another sealer (I used three coats of shellac). Simply brush on the shellac and let it dry according to the usual instructions. Be sure it is completely dry before working with it, as the shellac will pick up fingerprints and debris, ruining the fine detail you get from an alginate mold. Shellac also sticks vigorously to many rubbers, so you may also want to rub a coat or two of wax over the part once the shellac is dry to both improve the seal and decrease the chance it will stick to the rubber for the mold.
3) Cut or sand off the end to create a flat surface to place against the bottom or the mold so it stands upright--you can use plaster sanding screen if the base isn't too uneven, or you can cut off the bottom of the part with a small, fine hand saw and then smooth it with sanding screen.
1) Shape and join the parts--for instance, my pig's feet came as two halves, so I cast two halves and then glued (with wood glue) the two plaster halves together. After glueing them together, I then used plaster sanding screen to shape the foot, getting rid of the excess where the two pieces didn't come together perfectly.
2) Seal it--since plaster is porous, you'll need to seal it with several coats of shellac or another sealer (I used three coats of shellac). Simply brush on the shellac and let it dry according to the usual instructions. Be sure it is completely dry before working with it, as the shellac will pick up fingerprints and debris, ruining the fine detail you get from an alginate mold. Shellac also sticks vigorously to many rubbers, so you may also want to rub a coat or two of wax over the part once the shellac is dry to both improve the seal and decrease the chance it will stick to the rubber for the mold.
3) Cut or sand off the end to create a flat surface to place against the bottom or the mold so it stands upright--you can use plaster sanding screen if the base isn't too uneven, or you can cut off the bottom of the part with a small, fine hand saw and then smooth it with sanding screen.
| « Previous Step | Download PDFView All Steps | Next Step » |
 |
Add Comment
|
