The damage to the outside can be repaired with a few different techniques, including filling in cracks and chips or scratches using fiberglass resin or epoxy putty then sanding down when cured.
The most difficult part may be removing any paint that has been damaged by overzealous repair work on an area before you start working there again as it will make your job much harder if not impossible for future coats of paint later.
How To Repair RV Exterior Fiberglass Damage
1. Remove Old Paint
In order to remove old layers successfully, take care not only scuff up solid surfaces like metal but also lightly rub solvents into all areas where removal is desired- careful use should leave no trace while duller finishes are what we’re after since they can be sanded off.
Our bodies and hands are good at removing coatings, but do not use steel wool on any surface that you want to retain a shine or it will remove the finish as well.
105-K Fiberglass RV/Boat Repair Kit
2. Choose Epoxy or Resin
A fiberglass repair process can be done in two ways. The first is to use an epoxy putty to fill the damaged area and smooth it over with a piece of wood or plastic so that it will “level out” before mixing up resin and pouring on top of it to create a new surface.
The second involves sculpting the area back out using traditional fiberglass resin and then smoothing down the excess once cured with some form of sander.
Some companies offer both processes but neither is particularly expensive compared to scratch removal for example, which can cost upwards of $600 per panel depending upon its size and location on your vehicle. This method is perfect for working around complex body shapes like those found on a vintage trailer.
3. Clean the Area
Once you have decided on which approach will be best for your project, start by cleaning the area first with some good soap and water or another easy to remove solvent like lacquer thinner before allowing it to dry completely.
The next step- if using an epoxy putty instead of actual resin- is to apply filler in layers until the desired level has been reached.
If sanding down after this point, work as slowly and carefully as possible while larger areas can be done more quickly than small ones such as corners or minor curves since they’re easier to see around when working in tight places.
Finally, use fine sandpaper (220 grit usually suffices) on all surfaces once fully cured and waterproofed so that the area you just worked on will level out with its surroundings.
5. Filling In The Areas
For filling larger areas, I have found that it helps hugely to mix the putty into a smooth paste and apply it from the tip of your finger or off a plastic spatula so that it can be smoothed out as much as possible- this also makes it easier to catch any ridges before they become too noticeable.
Now, let harden completely below a piece of plywood weighted down by some books we should remove carefully without damaging the new surface and sand lightly in order to make sure both are flat with each other whenever necessary until only an occasional ridge remains which is easily sanded away.
6. Adding Fiberglass
The next step is adding fiberglass resin (which is essentially a type of plastic) to the area and working it in thoroughly so that it will not drip down onto a perfectly good paint job.
Afterwards, you apply more on top as required and- once fully cured according to the instructions- sand lightly with some 600 grade paper until flat.
105-K Fiberglass RV/Boat Repair Kit
Once putty or resin has been added, any screw holes or other rough spots can be filled with a little bit extra material and shaped carefully before smoothing over again, especially if using epoxy putty since even small ridges are easily noticeable afterward although this is less common when working with actual fiberglass resin.
The last thing we want is for the new finish to look lumpy compared to what was there previously!
7. Level Surface
In order to make sure that both surfaces will be level with each other, it’s a good idea to use some sort of reference point like small metal or wood blocks in the corners and/or heavier objects like toolboxes between them so that you can work more easily.
With epoxy putty, I have found it helpful to smooth out the area around any screw holes as best as possible while leaving the screws themselves alone (as they tend to stand higher than the surrounding surface) and then covering up both your newly sculpted fiberglass resin and putty work with a piece of plastic sheeting taped down along all edges.
Two layers are better than one if cost is an issue but keep in mind that there will be weight added by whatever repair method employed for which reason make sure that the base is in tip-top shape before adding filler or epoxy putty.
8. Let It Dry
Carefully remove the plastic after this point has dried (which usually takes between 12 and 24 hours depending upon temperature) and then sand it lightly once cured through a few layers of increasingly finer paper until you are satisfied with the results.
The last step is to prime and paint any areas that will be exposed directly afterwards using whatever colour scheme you have at hand although some paints may not stick very well to fiberglass resin so make sure that’s been taken into account beforehand as well.