Fitting a fibreglass body kit requires patience, the right tools, and an understanding that fibreglass parts are typically supplied raw — they need trimming, fitting, priming, and painting before they look finished. This guide walks through the process from unboxing to painted installation, so you know what to expect and can get a clean result.
WHAT YOU'LL NEED
To fit a fibreglass body kit you'll need: angle grinder or Dremel with cut-off disc, orbital sander or sandpaper (80–400 grit), fibreglass-compatible primer, wax and grease remover, mounting hardware (push-clips, screws, or riv-nuts depending on the part), and ideally access to a spray booth or professional painter for the colour coat.
STEP 1: DRY FIT BEFORE ANYTHING ELSE
Always dry fit the piece before grinding, drilling, or painting anything. Offer the part up to the car and check how it sits. Mark with a pencil where it contacts the car, where gaps are, and where material may need to be removed. Custom-made parts will fit much closer than generic kits, but a small amount of trimming is normal and expected.
STEP 2: TRIM AND ADJUST
Using a Dremel or angle grinder with a thin cut-off disc, carefully trim any areas marked during dry fitting. Remove material slowly — you can always take more off but you can't put it back. Smooth all cut edges with 80–120 grit sandpaper. If the part has a mounting flange, this is where it attaches to the car's existing mounting points.
STEP 3: CLEAN AND PREPARE THE SURFACE
Before priming, the fibreglass surface needs to be cleaned and lightly sanded. Wipe down with wax and grease remover. Sand the surface with 180–240 grit to give the primer something to bite. Remove all dust with a tack cloth.
STEP 4: PRIME
Apply two to three coats of fibreglass-compatible high-build primer, allowing each coat to flash off. Once dry, block sand with 400 grit to level any surface imperfections. This stage is what determines the quality of the final paint. Don't rush it.
STEP 5: PAINT AND COLOUR MATCH
Take the primed part to a professional body shop for colour matching and painting. Provide them with your car's paint code. Once painted and clear-coated, allow adequate cure time before fitting permanently.
STEP 6: FINAL FIT AND MOUNTING
Mount the painted part using the appropriate hardware — push-clips, self-tapping screws into existing holes, or riv-nuts for panels without factory mounting points. Start all fasteners loose, align the part, then tighten evenly. Check the panel gaps and adjust as needed before fully tightening.
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