How to Troubleshoot Polyurethane Release Applications
Polyurethane is a durable, versatile material used to make a wide variety of products. Polyurethanes are polymers with a urethane group in their chemical structures. These chemicals can be made into foams, elastomers, paints and coatings. Some applications of polyurethane require casting it in a mold. During mold casting, it's important to properly apply mold release, which helps ease removal of the polyurethane from its mold. There are several symptoms of improper mold release application; all are reasonably easy to fix.
Instructions
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Try to remove the polyurethane object from the mold and watch for sticking or for the object tearing or breaking during release. If this happens, it's a sign that there's not enough mold release and more should be applied. It can also indicate that you're working at the wrong operating temperature; some types of mold release are sensitive to temperature and have an optimal operating temperature.
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Examine the molded part for flaws, bubbles or any type of disruption or disturbance in the pattern. This is an indication of poorly or unevenly applied mold release. The solution to the problem is to clean or wipe off the mold and reapply mold release, taking care that the release is evenly distributed or that there is less mold release. Bubbles can also indicate that the mold release needs more drying time before molding.
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Touch the molded part or look closely for solvents or excess mold release left on the item after removing it from the mold. These are indications that there's too much mold release. Again, solve the problem by removing the mold release and reapplying in a thinner coat.
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References
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