Measuring and Mixing Design-Cast 62

Before you start, make sure that the mixer and container are clean and free from residue from a previous batch.

Mixing ratio for DESIGN-CAST 62

100 parts by weight of dry mix (part A)
10 parts by weight of polymer (part B)
20 to 23 parts by weight of water

Yield (without added filler or aggregate): about 18 cubic inches per pound of dry mix or one-third (1/3) square foot per pound of dry mix at a typical thickness of three-eighths (3/8) inch.

Consistency of the mix should be pourable, and not too creamy (thixotropic).

Use a scale (preferably a beam scale for accuracy) to measure each of the ingredients: dry mix, polymer, water, and pigment if used. AVOID EXCEEDING THE MAXIMUM RATIO AMOUNT OF WATER—too much water tends to weaken the cast.

In order to get maximum strength, freedom from cracks, and consistent setting times, mix DESIGN-CAST with a mechanical mixer—not by hand. You can mix batches up to about 20 lb. using a Jiffy^® mixer, or a propeller-type mixer chucked into an electric drill or air-operated power tool. The recommended mixing speed for DC-62 is typically about 1,000 RPM. A rule of thumb to assure proper mixing is that the propeller diameter should be about a third to a half of the diameter of the mixing container, and that the mixing part should be completely submerged so as to avoid sucking air into the mix.

A suitable mixing container is a plastic bucket, a plastic salad or ice-cream container, or a stainless steel pail.

For best results, mix materials at 75°F or cooler. A lower temperature will give you a longer working time; however, do not expose the polymer to freezing temperatures.

Recommended mixing procedure

1. Place the measured amount of polymer in the mixing container
2. Add the measured amount of water to the mixing container
3. Add all of the dry mix and pigments (if used) for the batch to the mixing container
4. Mix about 30 to 60 seconds
5. Let the mix rest 3 minutes
6. Re-mix for another 30 to 60 seconds

Longer mixing times will reduce the working time, but will otherwise not harm the material. In any case, mix long enough to give a uniform, lump-free mixture.

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