How to Repair Acrylic & Fiberglass Stairs

Clean out the damaged area with a nylon brush to remove any debris and then wipe down the surface with a piece of cloth dipped in acetone.

Abrade the stair surface surrounding the damaged area with 80-grit sandpaper to prepare the surface for the adhesive. Cut away any flakes still attached to the stair with a utility knife.

Fill any cracks with a fiberglass sealer. Push the sealer into place with a putty knife, and then scrape the knife edge across the surface to level the sealer out. Allow the putty to dry for about six hours until it's hard.

Cut a piece of fiberglass cloth that’s about 1/8-inch larger on all sides than the repair area with a pair of scissors. Cut a second piece of fiberglass cloth 1/4-inch larger and a third 1/2-inch larger.

Mix the fiberglass resin with its hardener in a small bucket with a wooden stick. Add the resin to the bucket first and then add the hardener using the manufacturer suggested hardener-to-resin ratio. Stir thoroughly.

Brush the surface of the repair area with the resin, and then place the smallest cloth piece over the damaged area, centered over the damage. Brush a layer of resin over the cloth to smooth the cloth out and to fill the pores in the fabric. Spread out the resin slightly away from the surface of the cloth and then place the second fiberglass cloth in place. Brush over that cloth as well before adding the third layer.

Cover the final layer of cloth with resin, covering about 1/2-inch of the surrounding surface as well. Use a feathering technique with the edges of the resin so that it blends in with the surrounding surface without creating a visible edge. Wait overnight for the resin to cure.

Sand the resin smooth with 200-grit sandpaper placed over a sanding block. Wipe off the sanding residue with an acetone damp cloth. Allow the acetone to dry for about 30 minutes.

Cover the entire staircase with the fiberglass primer using a paint roller. Wait approximately 30 minutes and then cover the primer with a layer of fiberglass paint, also using the paint roller. Allow the paint to dry for 48 hours before using the stairs.