Fiberglass Body Prep

By alternating colored hardeners (green and red), you can use multiple layers of fillers as guidecoats as you sand. Note the pinkish tint on the left and the greenish tint on the right.

Experienced bodymen can feel low or high spots with the palm of their hand. With a little practice, so can you. Try wrapping a thin cloth around your hand first; sometimes this helps you feel even better.

Low areas are filled with Evercoat Z-Grip Lightweight Filler using a rubber spatula. Keep it neat now. You'll save yourself lots of sanding time later.

The filler must be sanded down with 180-grit paper on a flat block.

Aerosol and powdered guidecoats can be applied to check for high and low spots. In a commercial paint shop, primer must (for legal reasons) be shot in a spray booth, but these dry guidecoats can be used in the bodywork area of the shop as well.

Once again, sand with 180-grit paper and watch for areas that are lower than the rest (they will still have the guidecoat in them).

The guidecoat will look like black grit until it's sanded off.

After the car was sanded with 180-grit, Poindexter laid on a coat of PPG Quicksand 2K urethane primer in the booth.

Now it's time to sand with 180-grit. Once again, the paper is wrapped around long, flat sanding blocks to use on flat panels. Don't use power tools for final sanding.

You can see the low area in the middle of the smooth section here. This dent is too slight to be seen by eye, but flat sanding shows it up immediately.

This fender needed a thin coat of filler in some areas to bring them up to the correct height. Knock the top off of filled areas with 40-grit, then finish with 80-grit.

After the primer dried, poindexter laid on yet another thin spray of guidecoat. You can't get a car too flat! We're going to paint this car black, so any imperfections will be obvious.

Flat sanding blocks are made from plastic house trim and wrapped with paper for final wet-flatting. Commercial flat sanding blocks are also available from Dura-Block. Use only enough pressure to remove the guidecoat.

The flat sander is used to sand down the area until the dent is erased. Once the guidecoat has disappeared, it's done.

For curved areas like the roots of fenders, you can use curved sanding blocks like this Dura-Block or make your own from wood or thick hose.

On fiberglass bodies, you will always find lots of pinholes that will need to be filled with non-shrinking body putty. Do not use finishing putty-it shrinks as it dries.

A round sander can smooth inside curves like this side vent.

Wet-sand with 400-grit, and then it's ready for paint. The Devin sits in the booth awaiting its paint job, which is also in this issue of KIT CAR!