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Estimating Compound Amounts

In order to obtain more accurate estimates of the amount of Cold Mold Compound needed to fill a particular mold cavity it is a good idea to write down the amounts of Part A and Part B used with each size mold. Use this weight as a basis for future estimations, taking into account the differences in the size and thickness of your models.

Kneading Part A & Part B

Mixing small amounts of Cold Mold Compound is easy to accomplish by simply kneading Part A and Part B together. The 2 minutes of working time is more than adequate to make a small or average size mold. This may not be the case with larger molds. When making larger molds it is important to mix the compound as quickly as possible but it is extremely important that the compound be mixed thoroughly. To make mixing quicker and easier, follow these steps:

• 1. Measure equal Parts A & B
• 2. Spread the separate parts into flat sheets approx. 1/8" thick
• 3. Place the sheets on top of one another and roll into a cylinder
• 4. Fold the cylinder in half lengthwise
• 5. Twist the cylinder and continue kneading until a uniform color is achieved.

Methods of Applying Pressure

Although Cold Mold Compound cures without heat, some pressure is needed to ensure a good mold. The most effective method of applying pressure to a mold during curing is to use a vulcanizer. The vulcanizer should be used COLD (not turned on) applying only enough pressure to keep the mold plates in contact with the mold frame. This method provides constant, even pressure to the mold and can be adjusted if necessary. Another method of applying pressure involves the use of C-Clamps or other similar clamps. The difficulty with using clamps is the unevenness of the pressure being applied. It may be necessary to use a stiff material along with the mold plates, as the plates may bend under uneven pressure (especially when making large molds). If clamps are not available, a heavy weight such as a large book can be used to maintain pressure during curing.

Powder Separated Molds vs. Cut Molds

Most molds can be made using the powder separation method with good results. This method is quick and has the advantage of very easy mold separation after curing. While traditional cut molds take longer to separate after curing, they also offer several advantages over powder separated molds. Perhaps the most important advantage is the increased control you have over where the parting lines appear on your final piece. This is especially important when molding complex models or those with elaborate surface textures. Another advantage of cut molds becomes evident when making large molds. Instead of mixing the Cold Mold Compound in two "batches" and having to worry about the short working time and shifting of your model, you mix the entire amount at one time, because both halves are made at the same time.

Wax Injection

While most molds made with Cold Mold Compound are as easy to inject as any other mold, care must be taken due to its relatively low durometer (35). As with other types of molds, injecting plates should be used to provide even pressure to the mold. The amount of pressure required depends on the size of the mold as well as the size and shape of the cavity. If too much pressure is applied, the mold may become distorted, resulting in inaccurate and misshapen waxes with pronounced parting lines. Conversely, if too little pressure is applied to the mold, the resulting wax may exceed the boundaries of the cavity. Simply stated, the wax injection process may require some trial and error to ensure accurate waxes.

"Proof" Models

The low cost and minimal time requirements of making a mold with Cold Mold Compound make it perfect for "proofing" wax models before they are cast. Instead of sending your original wax model to your client for approval, risking damage or loss of the model, wax injections from a cold mold can be sent instead. And since Cold Mold Compound is a 0% shrinkage silicone, wax injections can also be used to check for accuracy of size/fit. These molds can also be used to produce "master" patterns which can be altered in any number of ways for production purposes. The security provided by making fast, accurate molds of original models makes Cold Mold Compound invaluable to any modelmaker.

Alternative Uses

• Masking material for sand blasting patterns
• Take impressions from tombstones and memorials
• Rubber stamps
• Reproduce historic moldings and carvings