Step 1: Preparing The Mold
Begin by placing silicone mold rubber in its wood mold box. To help the mold maintain its shape, embed wood supports into the mold rubber. The lid should have holes which will allow the pressure of the expanding foam to escape. Apply Sonite Wax to both the lid and the holes in the lid to keep the expanding foam from sticking. Use ratcheting mold straps to firmly affix the lid.
Step 2: Dispensing, Mixing, and Pouring flexible foam
Measure out and premix flexible foam parts A and B. Add Black, Green, and White So-Strong pigments to Part B of the foam and mix together. Then, dispense flexible foam parts A and B into the mixing bucket and thoroughly and quickly mix the 2 components together. Immediately pour the foam mixture into one of the holes in the lid, and then pour more of the mixture into the other hole in the lid.
Step 3: Demolding flexible foam Casting
Allow the foam to rise and cure for 1 hour and then cut away any extra foam material. Remove the mold straps and take the lid off of the mold box. Once small pour vent spruces are cut away from the casting, the piece is ready to demold! Begin by inverting the mold and removing it from the wood mold box. To push out the wood supports, use a wooden rod. Now the mold is ready to be fully opened. Peel away the sides of the mold and pull the flexible casting away from the rubber mold. This reveals a perfect casting, requiring only a small amount cleanup!
Step 4: Finishing Casting
Cut away the flashing from the foam casting using a sharp knife. Apply talcum powder to give the piece a ‘white/chalky’ look. The piece is now ready to be used. These lightweight castings are easy to move and safe to handle. The flexibility and strength of the foam makes these castings very durable. The process can be repeated as many times as needed for a wall of lightweight prop blocks.

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