Let me reiterate the importance of working in a room with adequate ventilation and a respirator. The release agent alone is reason enough for it. Whew! Just as for foam latex, make notes of what you do for each batch. The more you use cold foam, the better your results will be.
Before beginning, place a cup or other container on the scale and tare it (zero it out):
1. Pour Part B into a container; add food coloring to tint if needed. Experiment beforehand for color and amount. Unfortunately, food coloring choices are rather limited compared to pigment selections for other materials.
2. Pour Part A into a container (the ratio is 65:35 B:A by weight; multiply the weight of Part B by.53 to get the weight of Part A; 35 divided by 65 = .53). You can pour both parts into the same container if you are able to accurately do so.
3. As soon as the two parts have been added together, mix them quickly. The best results will be achieved by whipping the mixture with an electric
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drill and wire whisk; bending a long piece of wire (such as a coat hanger) works well. If you mix by hand, stir the mixture as quickly as possible until the foam starts to increase in volume.
4. Immediately pour the foam into your mold and clamp the halves tightly closed. The setting time is usually around 8 to 10 minutes but can take longer, depending on the temperature of the molds and of the room.
5. Cleanup can be done with soap and water, but be prepared for the fact that you might not get all the foam off your tools. Definitely wear rubber gloves for this!
There is a heat reaction when the foam begins to rise; the foam might begin to rise very suddenly, so be careful to keep your working area clear of anything you care about. Urethane foam is quite unwilling to give up anything it envelops.