To fill the hole, first mix a batch of neat epoxy—with no filler—and wet out all the circles. Then mix another batch of epoxy, adding colloidal silica and low-density fairing compound until the mixture again has the consistency of peanut butter. Spread this second batch of epoxy over the entire surface of the hole being repaired and then start filling the hole with the cut circles. Begin by placing the biggest circle of mat on the bottom and the same-sized circle of cloth right on top. (In this repair, the mat fills the cavity and the cloth creates structural strength.) Squeegee out the air bubbles and continue placing smaller mat and cloth circles in the hole. Squeegee every layer before proceeding to the next. The smallest mat and cloth circle will be the upper layer. Finally, cover those two top circles with the cloth circle that is the same radius as the repaired hole.
Flatten the surface with the squeegee and cover with a sheet of polyethylene. Although exact curing times depend on the hardener you are using and the temperature and humidity, for best results let the repair sit overnight.
After the repair has cured, peel off the polyethylene and wash the area with acetone to remove any amines that might have been released during the curing process. Sand off the high spots, and if any low spots remain, mix a batch of epoxy filler and use it to fill them in. Let the epoxy cure. Continue sanding and filling until the entire repair is flush with the rest of the deck.
Wait three to five days before painting the repaired surface. It never hurts to reclean the area with acetone to remove any amines. Before you paint, wash the area with clean water.
If your deck has a painted antiskid finish, redoing a small section around the repair doesn’t make much sense because it is nearly impossible to match a paint color that has been faded by the sun. If you plan to cover a much larger area, first tape off the section you plan to paint. Next, prime the section—we like to use a two-part water-based epoxy primer. When the primer has cured, wash the surface with an ammonia-and-water solution. A quarter cup of ammonia in a gallon of water works nicely.
When using sand to create an antiskid surface, put the sand on the paint rather than in it. Several different types of sand work well, but don’t use common beach sand. Salt is difficult to remove as well as other bits and critters in beach sand that will make it far more difficult to get good adhesion. In addition, the grains will not be uniform and this will affect both the aesthetics of the finished product and the effectiveness of the antiskid surface. Considering the time and effort involved, do it right with commercial sand. Here again, a two-part water-based epoxy paint works well. After the paint has been applied sprinkle the freshly painted surface with sand.
After the paint has cured, rub a piece of wood over the surface to knock down any high spots. Then remove the loose sand with a vacuum or brush. Apply a second coat of paint and if necessary, sprinkle on some more sand and put on another coat of paint. Plan to use about twice the amount of paint you would use on a smooth surface of the same area. Remove the masking tape before the second coat has hardened completely; this will allow the edges of the paint to soften a little. When everything is fully cured the antiskid surface should be smooth and fair.