Following the repair of the inside of the fiberglass hood from the Arctic Cat snowmobile, it is time to tackle the outside portion of the repair.
The outside of the hood had gelcoat that had been damaged, and is in need of a cosmetic repair. The hood had been prepped with a grinder to remove loose pieces and provide an abraded surface that will have good bond strength.
The first step is to remove the tape that had been limiting resin intrusion. The resin was well on the way to curing prior to the tape being removed.
Next was to begin the actual repair. The area was taped off to limit the resin and filler getting onto the neighboring gelcoat. The tape was used more as a dam than as a flat edge.
The repair material was a filled epoxy resin. The first step is to apply the pure mixed epoxy to the the substrate. This is done prior to the application of the filler. It helps with the bonding process to have some pure epoxy between the filler and the fiberglass.
Then a batch of epoxy filler was mixed into a thick paste to be applied to the repair areas. Part of the challenge is to fill the voids to be level with the existing gelcoat. If they are too high, they will need to be sanded off. Too low and a bunch more filler will be required.
The filler paste takes a while to cure. Once it does, the tape can be removed.
Then the sanding can begin. Beginning with a coarse grit helps the work go faster, but there is greater risk of creating damage to the surrounding gelcoat. The first pass here was at 80 grit.
These areas were sanded by hand. Power tools are available, but the overlap onto the gelcoat would have been greater. Depending on your project, that may not be as important to you. Going after an area with power tools runs the risk of flattening out the entire area and removing a bunch of gelcoat. The whole profile of the are could end up being sunken down from the original profile.
There were still a few very minor low spots that required filler. This was more of a “skin coat” so there was not the need for all of the tape.
All of the areas were skimmed with a thin layer of filler. Following cure, they were sanded again, but this time only a few high spots were sanded with 80 grit. The next stage was some 180 grit, finishing with some 320 grit sandpaper.
The final sanding was to ensure a smooth transition from the repair areas to the gelcoat areas. Making sure that there were not any dips or lines in the repair transitions will help to ensure that the repair will not be spotted. Sometimes the hard edges can be seen with a visible eye, but an experienced touch is the best way to check out a transition. Running your entire hand (not just your fingers) over the repair will help you gauge the smoothness and straightness of the repair.
The last thing to do is to paint the repair areas of the hood.