There comes a time in every fiberglass boat’s life when waxing, polishing and compounding no longer do the job. The gel coat has faded to the point of no return or is chipped and crazed. In any case, it is decision time. Is the boat worth investing some time and effort in or do you simply take the course of least resistance and sell the boat?
A surprising number of folks have decided, for reasons economic or sentimental, to keep the boat and repaint it. So was the case with my family’s vintage 1972 sloop, Ternabout. This article reflects the details of that paint job. It will refer to specific brands and products, not because they are the best or only products on the market but they were simply the ones I chose.
Not all boat owners decide to do the job themselves.
There are hosts of competent shops out there that can handle painting projects with great skill. In fact, some finishes, such as AwlGrip or Imron, require professional applicators for a safe and effective job. However, this article is how one person did the job on his boat.
It has been said that proper preparation is 90% of a good paint job. It was certainly a challenge on my boat. The gel coat has faded and had been compounded several times. In addition, parts of the hull were crazed. It would require heavy sanding to get down to a firm base for painting.
The first step, however, was to de-wax the hull. The hull was made in a heavily waxed mold and further coats of wax had been applied over the years. All this had to come off for good paint adhesion. After a good cleaning with detergent and water, I de-waxed the hull with Interlux Fiberglass Solvent Wash 202. I used plenty of clean rags and wiped only in one direction.
I started out sanding with 80-grit sanding discs on my Porter-Cable 6-inch random orbital sander. The going was hard on the old gel coat so I soon switched to 60-grit. The rules in my boatyard require all sanders be used with a vacuum attachment to control dust.
Once I finished sanding with the 60-grit discs, I went back over the hull with 180 grit discs to get the 60-grit scratches out and prepare the hull for primer. I rolled on a coat of Interlux PreKote gray primer and let it dry. The PreKote instructions state that it should be sanded almost translucent, which I did with 220-grit sandpaper.
I then went over the hull and marked all the imperfections. Chips, gouges, scratches and pits were all marked out. These were then filled with Interlux Watertite Epoxy filler. Once the epoxy had cured, I carefully sanded these areas flush with the surrounding hull. After this sanding, I applied the second coat of PreKote primer and let it dry.
At this point I should have added a little of the final hull paint to pre-color the primer but forgot this step. After the primer had dried, I sanded it with 220 grit sandpaper and then wiped down the hull with Interlux 216 Thinner to get all the dust off. At this point, the hull was finally ready for the final color coats.
The painting was done using the “roll and tip” method. This technique works best with two people. The first person rolls on a thin coat of paint with a foam roller. The second person follows behind and strokes out the paint with a dry foam brush. The two people work on about a 2-foot by 3-foot section of the hull, at a time, progressing down the hull. Properly done, a rolled and tipped hull looks like it was spray-painted.
The key to proper paint application is the proper thinning of the paint. Unfortunately, it isn’t as easy saying, “Add 5.5% thinner”. It will vary depending on factors like temperature, humidity and wind speed.
I experimented with the paint before applying the full coat. I mixed a small amount of thinner with the paint and then rolled and tipped a small section of the hull. If the paint flowed out smoothly and left no brush or roller marks, I was good to go. Otherwise, I wiped the hull off and tried a little more thinner.
Once the proper thinner ratio was found, we were off to the races. My wife, Pat, and I could roll and tip a coat of paint on the 20-foot hull in about an hour and a half. I rolled while my wife tipped. She went through about two foam brushes per side, throwing the brush away when it gathered too much paint to tip properly. Depending on the conditions, I sometimes had to add a little additional thinner if the paint was becoming too thick due to evaporation in the paint tray.
For best results, Interlux recommends wet sanding between each coat with wet-or-dry sandpaper. I did wet sand after the first coat but not after the remaining coats. I did wipe down the entire hull with thinner before adding the next coat of paint. Depending on the weather and schedules, the next coat of paint was applied within several days.
Because I was applying a red top coat over gray primer (and forgot to add some top coat paint to the primer) I went with four coats of paint. Don’t try to do it in one or two thicker coats, the paint will tend to run and/or sag and the paint will take forever to dry hard.
I painted the hull late last fall but didn’t get a chance to launch the boat that year. The paint had ample chances to cure to a solid, hard finish. Don’t put your boat in the water before the paint has a chance to fully dry.
The final finish was excellent in terms of gloss and smoothness. I would give it a “5” rating (looks good from five feet away) but then I’m biased. Unfortunately, I didn’t save every receipt but I estimate it cost around $250 to properly paint a 20-foot hull. Not a bad price, considering the results as compared to the cost of a professional paint job. I’m not sure I would make the same decision on a larger boat, but this project turned out successfully.