Tag Archives: lost foam

Fabricating an Air Scoop

Using the Lost Foam Method

By Brian Knight

I used lost foam construction to fabricate a fiberglass air scoop for my son’s Formula Continental C race car. Our project started because a modification to the shape of the race car body necessitated the construction of a new air scoop. The air scoop is bolted to the car body so if either the air scoop or the body is damaged (a very likely scenario), the repair will be simpler. To fabricate the scoop, I made a Styrofoam male mold, surrounded the mold with fiberglass, and then dissolved the Styrofoam to leave a hollow part. I used Styrofoam to build the male mold for several reasons. It is readily available at most lumberyards, it is easy to shape with files and sandpaper, and it is easy to dissolve with lacquer thinner.

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he nearly finished masthead fitting with a duplicate of the foam mold. After the inside was cleaned out, additional fabric was applied to achieve the final exterior shape. The outside was faired and shaped before the topping lift and sheave were installed.

Building a Masthead Fitting

by Captain James R. Watson

Above: The nearly finished masthead fitting Captain Watson fabricated using the lost foam method of creating custom parts.

Here’s another use of the lost foam method to produce a custom part with a molded interior cavity. In this case, the part was a masthead fitting to hold an internal sheave and provide a route for the halyard to pass. This method can be adapted to a variety of other applications, as demonstrated in Fabricating an Airscoop. Continue reading →