I have a Wenonah canoe with a white gel coat finish. I’d like to restore scuffs and oxidation to max shine. Any ideas? Wenonah suggested 3M 05955 rubbing compound, but I wonder if that’s too aggressive. Makes me nervous. Thoughts?
First of all you should find out if it is really gelcoat and which type (vinylester, polyester, or epoxy). Depending on how deep the scuffs and scrapes are and really if there is any perceptible depth, they will probably need to be filled with new gelcoat Use the same type gelcoat that is on the boat if you can. I have seen it stated that epoxy will stick to either vinylester, or polyester, but neither of those will stick to epoxy. If your canoe does have a gelcoat finish, it very well might be polyester. In which case, it will make life much easier for you. Vinylester gelcoat has a very short shelf life and is much more expensive and far less available than polyester. In the off chance that your boat might have vinylester on it, I’ve been told that polyester will work.
Sand the cracks all the way to the fiberglass.
Mask off around the area to be repaired with masking tape.
Gel coat consists of three parts: the gel coat itself, a catalyst, and a surfacing agent to aid in the curing process. The surfacing agent is required for open-air cure of the gel coat. In place of a surfacing agent, you can seal off the repair with wax paper or plastic film. This keeps air out to allow the gel coat to cure completely.
Apply your gel coat with a brush. Try to apply it as smoothly as possible. This will save you time on sanding after it has cured.
After the gel coat has cured, it’s time for sanding. Start with a 400 grit sandpaper and sand the repair nearly flush. Try not to sand too much around the surrounding areas, as you can sand through that gel coat! You can mask them off to help prevent that. Wet sanding works best. Gradually work to finer grits (600, then 1200) before finally buffing it finished.
I copied and pasted the above from a kayak manufacturer, because it’s quicker than authoring a new instruction. If the procedure sounds a bit involved, it really isn’t that big a deal, and with just a little practice you can make the hull look like brand new. It is very helpful to have a real good power buffer for doing the final buffing. I would recommend the small Chicago Electric from Harbor Freight that you can usually pick up for about $52 on sale. You won’t need any special high priced polishing compound; Turtle wax Scratch & Swirl remover works great and it’s cheap. Use the power buffer at a very low speed when buffing and it’s worthwhile to use one of the special buffing pads that Harbor Freight sells for the buffer. That comes after the wet sanding with 1200 grit, or better wet, or dry paper. I use 2000 for the final. You will need to do the wet sanding on scuffs and scratches too–even if you aren’t filling them with new gelcoat. Be aware that the gelcoat is most likely very thin, so sand very sparingly and work small areas at a time. The sanding is all by hand.
One more thing: If you are applying new gelcoat, you will need to clean the area to be filled with Acetone just prior to applying the new gelcoat. Oh yeah and the air temperature needs to be at least 65 degrees, or more. Have fun.
I have gelcoat repair and restoration tutorials at: http://briannystrom.com/kayaking/tutorials/
There’s also a fiberglass repair tutorial.
It is a common misconception that gelcoat will not adhere to epoxy, but it’s not true. I have done it numerous times after repairing boats with epoxy and fiberglass. The keys are that the epoxy must be FULLY cured and the surface must be THOROUGHLY cleaned.
Using a heat source such as an incandescent lamp will cure the epoxy faster. Cleaning requires water first to remove any amine blush, followed by a residue-free solvent such as lacquer thinner or acetone. Once the surface is chemically clean, you can sand it to provide some “tooth” for a mechanical bond. DO NOT sand before cleaning, as you will drive contaminants into the surface.