I'd like to remove my deck lines and restore some shine to the faded fiberglass gelcoat of my 5 year old kayak. (Kayak is meant to be enjoyed so not concerned with minor scratches.) While archived posts on paddling.net usually suggest using a power buffer and compounds/polishes, a general web search has more hits on using the newer and expensive acrylic finishes. Close to $100 per container, these treatments supposedly last a year when the required 4 to 6 coats are applied. They seem more toxic than the traditional stuff. I assume that neither process will ever restore the boat to its original shine but once done and waxed, hopefully would look better. Has anyone tried both methods and concluded one offers better results?
...it's unlikely that you're going to be able to restore it without considerable elbow grease and abrasive polishes. I've played with some non-abrasive "finish restorers" and none of them worked worth a darn.
If it's really badly faded (getting chalky), you have to sand off all the damaged gelcoat to get to the original color. While many Brit' boats with heavy gelcoat will allow you to do this, most domestic manufacturers don't use as much (especially on decks), so you have to be very careful that you don't sand through it. With thin gelcoat, start with polishing compound or a product like "Dolphinite" to see if that will do the trick. If the gelcoat is badly damaged AND thin, you won't be able to restore the color and your best best is to sand it, prime it and paint it with a good boat paint like Interlux Brightsides.
You can see some photos of a restoration I did on a red Anas Acuta that had faded to orange in my "Gelcoat Repair and Restoration" album at the link below. I actually used the fading to make the deck two-tone in some areas.
I've also taken a purple Pintail that had oxidized so badly that it looked almost white in places and brought it back to a respectable color...if you like purple.
Both of these boats had thick gelcoat, so I was able to sand them aggressively to get down to the original colors.
Finishes… I’ve seen some beautiful and dramatic results with the multi-coat acrylics especially on more weathered boats… FOLLOW INSTRUCTIONS…
I’ve always gone the sand, buff, polish route but if it were a big job, after seeing some results, I would consider the acrylics (don’t know how long they last though).
Just a thought . . . Definitely not advice or an opinion: I wonder if the gelcoat can be sanded and layers of epoxy layered on, the same way you do with boat kits. Granted, you will no longer have a finish like the original gelcoat, but the almost clear epoxy can be tinted or left to “amber-up” the original gelcoat color.
Of course, from there one would have to sand and level the finish, then varnish over for UV protection, as in the case with kit boats. If this is possible (depending on the bonding qualities between the sanded gelcoat and the epoxy), you would have a new finish, scratch-free and shiny, albeit not likely in the original color. Care would have to be taken not to add too much epoxy, in order to maintain the boat at close to its original weight.
I am curious about this myself for different reasons. I have a gelcoat-finished “garden” bathtub, 25 years old, which has some wear under foot. I successfully patched chipped-out “bubbles” (exposing the black fiberglass layer) with epoxy years ago. I am thinking seriously of sanding down the gelcoat and re-finishing with tinted epoxy over it (black with anti-skid sand in it to protect against slipperiness).
Poly-Glo. Some time ago, (I can’t find the thread,) I asked for advice re: this. After many opinions, some from people who had actually used it, I decided to tackle my battered old Legend. The results were more than satisfying, and the boat still looks great. It may be one of the ones Greyhawk is refering to. I would definitely recommend it. Follow the instructions to the letter! Ken…
...as it's way too much work and there's no advantage to it. Primer and boat paint is a much easier solution if the gelcoat is not salvageable and it's easy to maintain.
If sanding/polishing the gelcoat does work, there is no point in putting epoxy and varnish over it, as it would just complicate maintenance. If a clearcoat over the gelcoat was desired, an automotive clearcoat would be a much better choice than epoxy and varnish.
On your planter, do whatever you like. Epoxy adheres to gelcoat just fine.