Body Prep and Painting

If you have never done bodywork before, talk to an auto body person who is familiar with working on fiberglass first.  Before painting your body and panels we recommend mounting them all on the finished car including all lights, windshield and doors.  After working with more than 3500 customers we have found the best results to be with folks who paint their body at the very end.  After everything is tight and aligned properly, we suggest removing the body and painting it off the car.  This eliminates over spray and keeps your nice work up to this point intact.

TOOLS:  100, 220, 400 grit sand paper, sanding blocks.

1.      Remove all trim, doors, windshield etc. before beginning body work

2.      Take extra care to sand away the fibers and strands specifically around the roll bar area. Finished flange around door should not exceed ½” to make sure the press-on door trim fits.

3.      The primer gel coat sands easily, and is a forgiving material to work with.  Remember that the body comes out of the mold with a wax release compound and a thorough cleaning with a wax remover is the best way to begin this job.  After the body is cleaned you can begin the sanding steps.

4.      The parting line left from the mold in the gel-coat needs to be ground down in a v pattern until you have removed all of the gray filler material down into the seam.  In some cases this filler may be more then a 1/16” deep.  If you do go up to 1/16” deep or more into the body, you should fill the area back up with fiberglass and resin, many customers have used 3M brand HSRF(High Strength Repair Filler) with much success.  Do not simply fill the area with a normal puddy filler.  For a car that will be painted a dark color such as black or dark blue it is very important to understand the nature of fiberglass as a material.  The vinyl ester resins used for these bodies will shrink with a final stage of curing with the elevated temperatures that are present in the sun on a dark car.  The parting seams and any area of body filler repair should be given at LEAST several days to cure.  If you want to heat cure the bodies do not exceed 140° F.  When the final paint is applied it is very smart to add several coats of clear to those areas where work was done so that years later you or the next owner can simply sand out and buff any imperfections that may develop.

5.      Much time and energy was spent on the mold so that the parts line up evenly and don’t have a different height when you begin sanding.  Take your time at this final fitting stage and you’ll be rewarded with a fine finish, and a perfectly straight body.  Of all the areas to be a perfectionist this is the one.

6.      Block sand the entire body surface with 100 grit sandpaper.  For flat sections you can use a harder rubber sanding block.  For curved sections, use a firm sponge at an angle to the curve that you are sanding.

7.      Make sure the body is clean and grease/wax free before priming.

8.      Allow the bodywork or repairs performed to sit for several days outside in the sun or at elevated temperatures to allow the repair materials to cure.

9.      Prime the body surface with a polyester primer/surfacer such as featherfill. Make sure you prime with a polyester primer over all areas of repair. This polyester primer is the same chemical base as gel coat and acts as a barrier between the raw fiberglass and the topcoat you will be applying.

10.  Block sand with 220 grit paper.

11.  The last coat of primer should be a different color so that you can see scratches or flaws that were missed the first time around.  Pay particular attention to the areas on the top of the car since these are the most visible to the person looking at the car.

12.  After the primer is dry, use a 400-grit wet sanding paper with wet sponge soaked frequently to finish the surface preparation.  You will see the heavier 220 grit scratches in the surface you are sanding with 400 grit and you want to sand until these heavier scratches are gone.

13.  While you’re wet sanding, you know you’re finished with an area when it appears foggy and water doesn’t bead up on the surface. Wipe the area with a flat squeegee while sanding to inspect the surface for defects.

14.  Spray a sealer coat over the primer and follow this with your first paint coats.  The modern two stage basecoat/clear coat urethanes are the best choice since they offer the workability of the lacquer paints with the flexibility and resistance to cracking of the enamels.  The clear coat should be fairly thick since you can repair this layer in the future if something happens to the cars finish.  We’ve seen bad looking scratches repaired if the scratch didn’t pass through the clear.

15.  Go slow.  It is amazing how many people (including us) rush the last steps in order to get the paint on the body when only a few more hours would give you a show car.  Keep in mind that paint is impossible to keep looking perfect if you are going to put miles on the car.