[EBEACH]

Here is a suggestion from DIY boat owner magazine

Stucco Style Repairs The most common style of random pattern non-skid resembles stucco and is applied in much the same way, using a paint roller loaded with gelcoat thickened with colloidal silica. This style of non-skid also provides an excellent surface underfoot and is by far the easiest to apply. Roll-on slip-resistant coatings, however, are still subject to matching problems. It's relatively easy to produce a reasonable match to the original deck texture but an exact match is much more difficult and not guaranteed by most repairers.

Minor differences in gelcoat viscosity and rolling technique cause large differences in the non-skid texture. With practice it should be possible to get close to the original texture but for the repair to be considered acceptable by the customer, close may not be good enough. Once again, to minimize side-by-side comparisons of texture (and color) it makes sense to isolate the new non- skid from the original surface by creating a distinct boundary or cut-off for the repair area. If the original non-skid is arranged in panels, then refinish the whole panel. If the non- skid is continuous from stem to stern it makes sense to create a smooth border or spillway, as outlined above to separate the new area from the old. Again, a matching break on the other side of the deck is considered mandatory to preserve symmetry.

Application:

STEP 1 PREP Presuming the repaired surface has been filled and faired with gelcoat and sanded smooth with 80- to 150- grit paper, remove all dust with com- pressed air and wipe it with a lint- free rag damped with acetone (or lacquer thinner). To simplify masking, complete adjoining repairs to smooth gelcoat. Carefully delineate the non-skid area with 3M Fine Line, Long Mask or 233+ masking tape and seal the inside edge of the tape by rubbing it with a plastic spatula or the back of a fingernail.

STEP 2 MIXING Pour some of the color-matched poly- ester gelcoat pre-mixed with air-dry wax into a litre (quart) size paper bucket or smaller. Add clean colloidal silica (strained through a sieve if in doubt), a bit at a time to the gelcoat, and mix vigorously by hand with a paint stir stick. The mixing proceeds until the silica is absorbed and the gelcoat achieves the approximate consistency of mayonnaise.

STEP 3 TESTING At this stage, before adding catalyst to the gelcoat, it's time to test the mix for its appearance as non-skid. Scoop out a sample blob onto a scrap sheet of plywood and rollout using an 18cm 17") short nap paint roller. The thicker the gelcoat the taller the "peaks" left by the roller and the more aggressive the non- skid will be. (Aggressive non-skid is good for footing but can tear a lot of skin in the event of a fall.! Compare the sample roll to the original gelcoat and adjust the mix accordingly. Add silica if too flat; if too aggressive, add gelcoat. Keep track of the mix ratios so the same gelcoat consistency can be achieved batch to batch .

STEP 4 CATALYZING Here is where a pro's experience shows. Unlike epoxies, which have a fixed mixing ratio, polyesters are flexible and the catalyst ratio can be tailored to give more or less pot life and to compensate for ambient temperature. Mix ratio can vary from 2% to 5% catalyst depending on temperature" the type of catalyst used, and the working time needed. Regardless, working times are seldom more than half an hour. Once the catalyst is added and mixed, it's time to hustle.

STEP 5 APPLYING Give the work area a final quick , acetone wipe before the "hot" mix is thinly applied by trowel to the repair j surface. Work the mix with a roller to finish spreading it evenly over the surface. Initially, roller strokes are applied in a unidirectional pattern using firm pressure to distribute the gelcoat. Once the gelcoat is evenly spread ease pressure on the roller to avoid causing streaks. In small areas, a random back-forth-sideways action with the roller tends to give the most consistent results. On large open areas, like a foredeck, rolling in one direction with overlapping strokes is best. If, however directional streaks appear, correct these by rolling across them at right angles. Stop rolling the minute the gelcoat looks consistent, as it never pays to overwork the surface. Thickened gelcoat non-skid is usually applied with one heavy coat. It's important to avoid leaving overly thick areas, especially overlapping onto the masking tape. As soon as rolling is completed and while the gelcoat is still wet, carefully peel off the masking tape, pulling at a 45° angle away from the wet surface. If the tape is left until the gel has cured, it will be difficult to remove and leaves behind a ragged edge. Clean up with acetone.

STEP 6 DETUNING If the peaks are uncomfortably sharp after the new gel- coat has dried, lightly scuff it with 80-grit sandpaper. It should not scratch bare skin !