Gelcoat Repairs Revisited

Posted by Darrell Nicholson at 03:09PM - Comments: (3)

June 30, 2014

A Dremel tool smooths out a gouge in one of Practical Sailor's former work boats, a Parker 23 powerboat, before repair.

Probably one of the most frustrating projects when restoring an old boat is dealing with gelcoat cracks and chips. It would seem that these minor blemishes would be an easy matter to fix, but they’re not. Achieving the same level of gelcoat gloss, adhesion, and color of the original hull or deck is a kind of black art, and it is a field full of pretenders. You could run a weekend movie marathon featuring all of the YouTube DIY videos offering bad advice on gelcoat repairs.

Many boat owners simply throw up their hands and opt to paint the hull with a one-part or two-part paint, a project we’ve examined in great detail—from prep work to paint selection to refinishing tips—in our multi-part series on linear polyurethane (LPU) marine paints.

In an upcoming series of articles we’ll be looking at the art of gelcoat repairs—everything from color-matching to filling to spraying. We’ll also be looking at the various gelcoat repair products.

This week I got the chance to speak with Paul Lacharite of Mini-craft of Florida on the topic of gelcoat repair. Lacharite has been manufacturing gelcoat since 1976, and in 1980, he became interested in mastering the art of matching colors, helping to develop a system that enables repairers to quickly match the original color of almost every boat that ever hit the U.S. market. He now runs a series of professional workshops from October to March every year at the Mini-craft facility in Wildwood, Fla.

Over the years, Mini-craft has assembled an inventory of sample panels of the gelcoats used by most major watercraft built in America. Using these panels and some basic information from the boat’s manufacturer, they can match the gelcoat of virtually any boat over the phone. Since gelcoat—especially colored gelcoat—weathers over the years, achieving an exact match often still requires some onsite color-matching skill, but if a “6-foot finish” (a repair or refinish job that is undetectable from more than 6 feet away) is all you want, Mini-craft’s in-house blend will be a pretty close match.

Mini-craft’s products and tools are geared to the professional, but they sell directly to the consumer as well. Unlike other gelcoat suppliers, they don’t just can and label gelcoat made elsewhere, they make it themselves at their Wildwood facility. They offer different grades of gelcoat, and all the equipment you would need to carry out repairs. However, given the challenges of many gelcoat projects, Lacharite reluctantly sells to the average Joe.

“People don’t want to follow instructions ,” he explained. “It’s human nature. And then, when something goes wrong, it’s never their fault. It’s the product.”

One of the most common errors Lacharite sees happens when a do-it-yourselfer or pro wants to spray apply gelcoat to a small area after a repair. For small repairs like this, we use a Preval sprayer, a process I outlined in my previous blog post on gelcoat repair. As it turned out, my own advice in the blog post, based on instruction from a local boatbuilder who’d made hundreds of such repairs, was a victim to this cycle of misinformation. (It has since been amended.)

“People are always advising to use acetone to thin the gelcoat,” Lacharite said. “This is wrong for many reasons.” In summary, he explained, if you use acetone to thin the gelcoat for spraying, you will shorten its life, and get a duller, rougher finish. Styrene is no better, he said; it will cause the gelcoat to yellow. What you want is a properly formulated reducer, something that Mini-craft supplies with its repair kit.

Until recently, Mini-Craft used to sell a handy aerosol gelcoat repair kit, but Lacharite said it became too expensive to produce. The company is now working on a similar kit using the Preval sprayer.

Look for our update on gelcoat repair early next year, and if you have some repair products or techniques to share, comment below or drop me a line at practicalsailor@belvoirpubs.com.

Comments (3)

Absolutely timely. I just bought a 1988 MacGregor 26D and have had the mis-fortune to have docked it to the outside dock this 4th of July weekend. When I came Back on the 5th of July all the boats on the dock had their fenders lying on the dock rather than in-between the boat and the dock. I found our it because of all the boats going past on the river channel never slowed down as they were passing our marina. so their wakes were so high that they caused the fenders to rise out of the water and land on the dock. needless to say we all have gel-coat repairs to do. What do you recommend to thin the gel-coat so it can be used with the PREVAL Sprayer?

Posted by: Brent H | July 12, 2014 8:28 PM    Report this comment

Great, it's amazing how many different whites you have to mix to get close to matching the original weathered gelcoat, and that's only the white. Anything to make it easier with less guess work.

Posted by: Paul G | July 2, 2014 11:26 PM    Report this comment

Very timely. Have a project to do on my 1982 Cape Dory 25D. I think that the "6-foot finish" will be very acceptable. Looking forward to the series.

Posted by: DOUGLAS H | July 2, 2014 3:33 PM    Report this comment


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