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Showing posts from November, 2019

Copying a Profile Using Liquid Urethane Foam

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I needed to copy the basic shape of a part of my car so I could work with it without damaging the original. It's part of the rollbar which is covered in leather. If I had a fancy scanner and 3D printer, I could have easily done this. Instead, I did it the manual way using aluminum foil and liquid urethane foam.

Liquid urethane foam comes in two parts that are mixed together in equal measures. The amount of rise from the foam is dependent on the weight per cubic foot. The range of densities goes from a very light half pound per cubic foot to a very hard and dense sixteen pounds per cubic foot and even more. The more dense the foam, the harder it is and the more abuse it will take to damage it.

Once mixed, the foam rises very fast, in the order of a few minutes, and then sets to a very hard material in about twenty minutes total. While it is rising, the foam itself exerts very little force on the material constraining it if it is allowed room to rise completely. Constraining the fo…