Return to... Contenti Moldex Instructions Contenti Moldex

• Things you will need:
  • your model
  • Moldex mold rubber
  • mold frame
  • small brush
  • small quantity of mica powder
  • pair of mold plates
  • 6 brass locators
  • mold cutting knife & blades
  • sprue rod and button
  • flexible steel ruler
  
  
  

Step 1. Make sure that your model is clean and free of chemical residues from natural rubber. A high polish is very desirable.

Step 2. Cut sections of Moldex to the length and width of your mold frame. Moldex is 1/4" thick. Use 1/2", 3/4", 1", or 1-1/2" thick mold frame. Peel off paper backings from the Moldex and conserve two pieces of this paper.

Step 3. For a 1" thick mold, place two sections of Moldex into your mold frame (or more or fewer depending upon mold thickness). Press the rubber to the bottom of the mold frame. Position your model in the center of the rubber. Press your model into the rubber until the top edge of the model is nearly flush with the rubber surface.

Step 4. Take six brass locators and fold each of the four prongs on each locator toward the center of the locator. After bending the prongs, press each locator onto a flat surface so that the prongs are all flush with the table surface. Position one locator at each corner of the mold bottom and press down about 1/16". Locators should be at least 1/8" away from the side walls of the mold frame.

Step 5. Lightly brush mica powder over the entire surface of the rubber and blow off any excess powder from the surface. Rub off any powder that has coated the model.

Step 6. Place your sprue button and rod into position, making sure that the sprue rod is at least 1/8" away from the model. Press down half-way.

Step 7. Take a small piece of paper and fold it at a 90 deg. angle. Place one flap against a wall of the mold frame with the other flap resting on the mold. This step will facilitate mold separation after vulcanization. Take the remaining, un-powdered rubber and place it, one section at a time, over the bottom sections of the mold. Press the top section down firmly until it is in complete contact with the bottom section.

Step 8. If, after pressing the top section down, any areas of the top surface are below the top edge of the frame, you may fill these areas with scrap rubber.

Step 9. If, after pressing the top section down, any rubber is above the top edge of the mold frame, it is necessary to shave off this excess rubber. A flexible steel ruler is useful for this purpose. grasping the ruler with both hands, place it at the center of the top surface and draw it toward you. Rotate the frame 180 deg.and shave the other half of the top surface.

Step 10. Along the four top edges of the rubber mold, cut a small bevel, no more than 1/8" wide. Repeat this step with all four bottom edges.

Step 11. Take the two pieces of paper backing that you have saved and place one over each of the exposed rubber surfaces.

Step 12. Place two clean metal plates over the top and bottom of the mold frame. Install the mold frame and plates into a vulcanizer preheated to 325 deg.F. Turn the handwheel of the vulcanizer until finger-tight, but not tighter. Vulcanizing time is calculated on the basis of mold thickness. 15 minutes per 1/4" of mold thickness.

Step 13. Remove the mold and frame from your vulcanizer. Take off the aluminum plates. To minimize shrinkage, allow the mold to cool naturally (dousing in water results in shrinkage of a ring wax pattern of up to a half-size).

Step 14. Remove the cooled mold from the mold frame by inserting a steel rule between the mold and the frame. Press the mold out.

Step 15. Place your thumbs at the point on the mold where the piece of paper protrudes and pull the mold apart.

Step 16. Remove the model from the mold. Cut a gate in both mold halves to join the sprue to the model cavity.

Step 17. Vent any prongs by putting a vent from the tip of the prong to the edge of the mold. Use this technique for any part of the mold that does not fill properly. Venting can be enhanced simply by placing powder in the vents.

Injecting wax into the Moldex mold
You don't have to powder a Moldex mold before injecting wax into it! This is why your waxes are produced with a shiny, glazed finish. This shiny finish, coupled with Moldex's excellent rendition of detail, will produce a casting with a finish superior to anything you've seen before.