Learn the Difference Between Painting Fiberglass and Metal

Have a fiberglass hood? We have more of them in the fleet than OE steel. How about fiberglass fenders on a steel car? The parts get along, but the paint might not. So if you are ready for that DIY spray job, we will let you in on the subtle differences between painting the two so you can get the job done right. We stopped by Elite Auto Restoration in Paramount, California to see how pro-painter Praveen Singh does it. The Elite guys restore muscle cars with ‘glass hoods and complete hot rods every day, so they are used to this.

Parts List
2K Primer Surfacer Gray LE3004S
Activator (Base) WB2075
Activator (Primer) LE3075S
Controller WB2045
Etch Primer 22880S
Etch Primer Reducer 22806S
Multi-Panel Clearcoat LE5100S
Sealer Gray LE3040S
Silver Cromax Pro Base Color ECN01
Surface Klean A-3990S
The fiberglass demo part was a used hood with a bad rattle-can paint job and some chips and scratches. Victor Rodriquez sanded all the paint off with a disk orbital sander and 80-grit paper.
The fiberglass demo part was a used hood with a bad rattle-can paint job and some chips and scratches. Victor Rodriquez sanded all the paint off with a disk orbital sander and 80-grit paper.
The cracks and chips were repaired with SMC fiberglass resin, ground flat with a 40-grit Roloc disk, then the entire hood was coated with Evercoat filler and sanded again with 80-grit until the surface was smooth.
The cracks and chips were repaired with SMC fiberglass resin, ground flat with a 40-grit Roloc disk, then the entire hood was coated with Evercoat filler and sanded again with 80-grit until the surface was smooth.
After the sanding, the hood was wiped with Surface Klean and a tack cloth.
After the sanding, the hood was wiped with Surface Klean and a tack cloth.
With a clean surface, four coats of primer were applied after waiting for the flash time between coats. There was no sanding between coats at this point. After the top coat dried, the fiberglass was sanded again by hand with 220-and 400-grit sandpaper.
With a clean surface, four coats of primer were applied after waiting for the flash time between coats. There was no sanding between coats at this point. After the top coat dried, the fiberglass was sanded again by hand with 220-and 400-grit sandpaper.
After the final sanding, the hood was cleaned with anti-static water-based cleaner and sprayed with one coat of sealer.
After the final sanding, the hood was cleaned with anti-static water-based cleaner and sprayed with one coat of sealer.
Using a Sata gun and a 1.4 tip, Singh sprayed one and one-half coats basecoat in Cromax Mosaic Bright Mercury Silver. Then it was ready for clear.
Using a Sata gun and a 1.4 tip, Singh sprayed one and one-half coats basecoat in Cromax Mosaic Bright Mercury Silver. Then it was ready for clear.
Singh uses this DeVilbiss paint gun to spray primers and sealers, but the tip sizes change for the medium. For the sealer and clear, Praveen uses a 1.3mm tip, and a 1.4mm for the base coat.
Singh uses this DeVilbiss paint gun to spray primers and sealers, but the tip sizes change for the medium. For the sealer and clear, Praveen uses a 1.3mm tip, and a 1.4mm for the base coat.
The clear coat can kick-off (read: dry) in less than five minutes, allowing the painter to work around the room and start back at the first piece when the last one is sprayed. Praveen did two laps of clear.
The clear coat can kick-off (read: dry) in less than five minutes, allowing the painter to work around the room and start back at the first piece when the last one is sprayed. Praveen did two laps of clear.
Unlike the fiberglass hood, the metal parts were new, requiring a different series of steps.
Unlike the fiberglass hood, the metal parts were new, requiring a different series of steps.
The sheet-metal parts were first sanded with 150-grit then 220, cleaned with acetone, and sprayed with a metal-etching primer.
The sheet-metal parts were first sanded with 150-grit then 220, cleaned with acetone, and sprayed with a metal-etching primer.
After the etching primer, Praveen did not sand, but added four coats of standard primer.
After the etching primer, Praveen did not sand, but added four coats of standard primer.
After priming, the metal was sanded with 400-grit just like the fiberglass and made ready for the sealer step. At that point, both the sheet-metal and fiberglass parts were sprayed with base coat, then clear coat the same way.
After priming, the metal was sanded with 400-grit just like the fiberglass and made ready for the sealer step. At that point, both the sheet-metal and fiberglass parts were sprayed with base coat, then clear coat the same way.
Source: hotrod.com

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