Fixing minor cracks and seams at a fiberglass shower pan may restore the pan into a uniform finish. While big cracks often indicate problems that patching may not correct, minor repairs are rather easy for a do-it-yourselfer. Gelcoat repair kits for marine and other wet fiberglass repairs are available at many home centers and marine stores; many come in a number of tones which closely match fiberglass shower pans. Similar to the majority of superficial repairs, preparation is the key to a uniform look.
Clean the shower pan using a fluid toilet cleaner along with a bristle brush. Turn on the water and rinse off the residue and cleaner. Dry the pan using cloth towels or rags. Use as many blankets or towels as necessary to completely dry the pan.
Put on safety gloves and a dust mask. Sand the region in a split, gouge or pit at the fiberglass using a fine-grit sanding block. Use light pressure on the cube to avoid sanding through the surface layer of this fiberglass.
Apply a thin layer of gelcoat patch on a break from finish to end with the provided applicator. Apply a modest quantity of gelcoat in a pit or gouge. Smooth the gelcoat to a uniform finish with one or two strokes of the applicator.
Refer to the instructions and permit the gelcoat to completely cure. Lightly sand any imperfections and also apply a thin layer of this layer, if necessary, to get a uniform look.