How to Make Car Body Moldings

by Lynn Rademacher

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Customized car parts can be expensive and difficult to find. Trying to find that perfect spoiler or other car body component can lead you to costly auto body shops that often leave you thinking you'll have to settle for a standard product at a premium price. Fortunately, you can create your own custom auto body parts by molding them out of fiberglass and foam. These parts can be molded in your own garage, giving you the pride of making the part yourself and saving you money in the process.

Step 1

Draw an outline of the part to be created on a block of styrofoam. This outline will act as a guide to cut out the final shape of your desired design.

Step 2

Using your utility knife, cut away the foam to form a styrofoam model of your part. Don't worry about making all of the edges smooth. Just make a rough cut of the desired shape.

Step 3

Sand the styrofoam with 180-grit sandpaper to smooth the part into the final desired shape. Take time with this step. The foam will sand quickly so if you aren't paying attention the overall shape may be altered from what you had in mind. Step back from the piece frequently during this process to view it from a distance and make sure you are shaping it correctly.

Step 4

Cover the shaped styrofoam in adhesive resin applied with a paint brush, and cover the shape with fiberglass cloth. Press the fiberglass cloth into the styrofoam with a hard roller. Allow the piece to dry for 12 hours. Repeat the process until four layers of fiberglass cloth have been applied to the foam sculpture. Allow the part to dry for a full 24 hours after the final layer of fiberglass has been applied.

Step 5

Paint the fiberglass part with a colored finishing resin. The finishing resin can be purchased from your local auto body shops. The store can match the resin to the rest of the paint on your car by using the paint code from the car. Apply the finishing resin in thick coats with a paint brush.

Step 6

Allow the finishing resin to dry until it is tacky to the touch, and then apply the next layer. Repeat this process until a minimum of four layers of finishing resin have been applied. Allow the part to cure for three to four days after the final coat has been applied.

Step 7

Examine the auto body piece for rough or uneven spots after the resin has cured completely. Sand the rough spots with 180-grit sandpaper to smooth out the surface of the piece. The colored resin will ensure that the sanding doesn't result in blemishes.