Cabintop Gelcoat Cracking Repair

[cburger]

Well she is a 37 year old boat and the cabin and cabin top is due for a complete repaint. As part of this I will have address the issue of cracking gelcoat on the cabintop, predominately in the area where the non-skid was applied. I have spoken with a friend on the west coast with the same model boat who had the same problem and has indicated that the only solution is to grind all the old nonskid off and make any required repairs the re-apply new gel and broadcast some sand to make the non skid pattern.

My issue is that when he did this project he removed all the deck hardware, which entails taking all the interior headliners down and unbolting and re-bedding, etc, etc. as well as the huge mess of grinding off the old gel. At the end of the day a mind numbing project that will end up causing me a year of sailing.

So here is the question, what about over-coating the existing nonskid with a product like Durabac Non-skid Safety Coating for Your Boat or Ship , I have used this product on customers decks as well as my own boat and it is one tough urethane coating, and a much greater elasticity than traditional marine paints. The cracks are very fine and don't appear to be penetrating through into the resin. The gelcoat appears to be still bonded very strongly to the glass. I have tried chiseling and using a scraper to see if could be loosened and it is still rock solid. So the thought would be to overcoat the existing nonskid areas and encapsulate and stabilize the old gel and save mucho, mucho hours on what will be a brutal job anyway, thoughts here please?

[SVTatia]

Before you do anything, determine the cause of the cracking. Is there a stress point under deck? Is the deck not supported and flexing? Is the gel coat too thick?
If none of the above and after you sand the top coat you see that they very fine (not wide), you may overcoat. Otherwise you have to open them up, fill with epoxy then overcoat. But that the cracks may still reappear.

[cburger]

It appears that the non skid on this vessel was not molded to the original cabintop and was sprayed on as the boat, (A kit) was being finished, I can see sand in the gel. Yes it is pretty thick but there are literally hundreds of fine cracks. As the Durabak is a very thick, elastic material I was thinking that I might not get print thru from the substrate. It was recommended that I try a test area to see how it holds up, my issue with that is who cold predict how long it would take to see print through, the other issue is that once the Durabac is applied it would be almost impossible to remove. I had residual Durabac on a mixing paddle used for a job and I could not cut, scrape or burn the product of the tool, very impressive stuff, but bonce applied your kind of committed.

[SVTatia]

Originally Posted by cburger

... It was recommended that I try a test area to see how it holds up, my issue with that is who cold predict how long it would take to see print through...

True, but you'll still have to either lift or sand the blue non-skid and see how is the glass/gel coat under it. If you find that the cracks or crazings are small enough, just paint after sanding it. Since Durabac is so hard to remove you better do it right the first time - unfortunately you will not be able to get away from a lot of sanding....

[minaret]

A year for a 32 cabin top? Don't think so. Just grind off all the old gel and into the glass a bit, lay a couple layers of matt in poly over the whole thing, fair it, gelcoat it, sand it out and lay out waterways, shoot them with gel and polish, reverse your tape and shoot the skid. Done, easy peasy. I recently did a Westsail 32 cabin top in flex mold in under a month. And that's a much more daunting task than regular skid. Just don't be afraid to fire up the 16 grit and it goes fast!

[roverhi]

Our W32 was laid up on a cold day in Costa Mesa. Apparently the gel coat ran to to the low areas of the mold because it was slow kick and they kept spraying it on. Gel coat on cabin top was way thick and cracked continuously.

Only solution was to grind it down to bare glass. Only took a couple of days for the cabin top. Used a heavy duty Milwaukee sander/polisher (2500rpm) with an 8" foam pad and 100 grit sandpaper to grind it down. Relatively slow rpm of the grinder, mild grit on the paper and large foam pad gave a quality gouge less finish that didn't need any additional prep work. Just used Awl Grip epoxy primer and LPU top coat with grit.

Just refinished the deck on my current boat. A $10 an hour helper and I pulled all the hardware, winches, windlass, ports, hatches, grab rails, pedestal, chain plates, and the cap rails in 5 days. I reinstalled most everything by myself so it was a lengthier process putting it all back