Cold Mold Directions

Directions for Cold Mold

1- Packaged in two containers, part A and part B Cold Mix 

 

  • Things you will need:
    • your model
    • Cold Mold Compound
    • mold frame
    • pair of mold plates
    • mold cutting knife & blades
    • sprue rod and button
    • clamps, or heavy object

 

STEP 1. Measure out equal parts of Part A (light blue) and Part B (purple) so that when combined they fill the entire mold frame you are using. It is recommended that the amounts be weighed for accuracy to ensure proper curing of the compound.

STEP 2. Rapidly knead together both Part A and Part B until a uniform color is obtained. You have a total working time of approx. 2 minutes, so work quickly. Once the compound is entirely mixed (with no streaks of color) divide the compound into 2 equal parts.

STEP 3. Working quickly, press 1/2 of the compound into the mold frame making sure that the compound reaches the bottom of the frame (the frame should be on top of one of the mold plates). Position your model in the center of the frame and press it into the compound until the top edge of the model is nearly flush with the surface of the compound.

STEP 4. Place your sprue button and rod into position, making sure that the sprue rod is at least 1/8" away from the model (as shown in the photo at right). Press down half-way.

STEP 5. Working quickly, press the other 1/2 of the Cold Mold Compound into the mold frame. The top of the compound should be slightly above the top edge of the mold frame to force the compound to fill the entire mold frame when pressure is applied.

STEP 6. Place the second mold plate on top of the mold frame, pressing the plate down with the palm of your hand. Although Cold Mold Compound cures without heat, slight pressure is needed to ensure a good mold. Pressure can be applied to your mold in any one of the following ways:

  • 1. Place the mold frame in a cold vulcanizer and apply pressure until the mold plates touch the top and bottom of the mold frame. This is the preferred method because it applies even pressure over the entire mold frame.
  • 2. Use an adequate number of C-clamps or similar clamps to bring the mold plates into contact with the mold frame.
  • 3. Place a heavy weight, such as several large books, on top of the mold frame.

STEP 7. After approximately 30 minutes under pressure the compound should be completely cured and the mold can now be removed from the mold frame. Remove the plates from either side of the frame and push the mold out with your fingers. Using a pair of scissors, remove the excess compound that has squeezed out from between the frame and mold plates.

STEP 8. The mold can now be cut open using a mold knife. To ensure that the mold halves remain properly aligned after cutting, registration locks (as shown at right) are cut into the corners of the mold as described below.

1.

  

Make a cut around the entire perimeter of the mold at the midpoint of its thickness. This cut should be no more than 1mm deep.

2.

  

Starting from one corner of the mold, angle your knife upward and make a 1/8" long cut along the perimeter while pulling up the top of the mold.

3.

  

Make the next cut straight across toward the center of the mold. Continue pulling up on the top of the mold to provide clearance for your knife.

4.

  

The final cut is angled downward toward the bottom of the mold, back to the mid-point of the mold thickness. 
This process is repeated for each corner of the mold.

An alternate method of ensuring alignment of the mold halves is to make a "wavy" or "zig-zag" cut around the perimeter of the mold (instead of a straight cut). This cut performs the same function as registration locks.

STEP 9. Once all four registration locks are cut, the rest of the mold can be cut apart. Working slowly, make small cuts towards the center of the mold. At this point, It is helpful to visualize the size, shape, and position of the model in order to locate it within the mold. Your objective is to have the parting line (where the two mold halves meet) in the most inconspicuous and easy to clean up place on the model. As the mold is being cut, the two halves can be pulled away from each other to make it easier to work, but it is important not to pull too strongly because the compound may tear and make your cut deeper than you want.

STEP 10. After the mold is completely cut and the model, sprue rod, and button are removed, gates are cut into both halves of the mold to join the sprue to the model cavity (as shown on the right). Vents can now be cut into the mold to ensure complete filling during wax injection or white metal casting.