I have seen several people ask how to repaint the coaming and mine could use a new finish.
The coaming is held in place with screws on older boats, the same way other hardware is mounted, except these screws have a much finer thread pattern. There are no bolts on the underside (that I know of) so all you need is a flat-blade screwdriver to remove it.
You may have to pry the coaming from the deck if a sealant has been used for waterproofing. A putty knife should get the job done without damaging the deck.
Newer boats have coamings that are riveted in place. To remove these, use the same procedures listed in the “rubrail” section (you may need a larger drill bit for this).
Painting the coaming can get interesting. I suggest avoiding spray paint. I tried Krylon on my last boat and was not pleased with the results. Even after sanding and priming, the topcoat would scratch off easily (if anyone has had success with spray paint, let me know what brand you used).
For a bare coaming, that is, one that has not been painted, you will need to sand it just enough to get the glossy top layer off. I used a 120 grit and sanded it until it looked chalky. Here, the purpose is to only “rough it up” enough to give the new paint something to grab on to and bond. Once the coaming is sanded, give it a wipe down with Acetone to get the remaining particles out (it will look glossy when you first wipe it, but will return to a chalky appearance when it dries).
If your coaming has been painted in the past, you will get better results if you go ahead and remove the old paint before adding new coats (unless you know what type of paint was used before and plan to use the same type this go-round, it would be okay to paint over the old coats as long as you lightly sand it first).
Two options for paint removal: first one is sanding. This is time consuming and messy but, a tried and true method. Use a 100 grit paper. This should be tough enough to get rid of the paint, yet light enough to not damage the coaming.
Second option is chemically stripping the old paint. You have got to be careful on which stripper you use. Some will melt (literally) the coaming material. Most marine stores will have a stripper that is safe to use on fiberglass and plastics. I used a product called “Pro Stripper” and it works great. So far, it has not damaged the coaming. Pro Stripper is available at Lowes and Home Depot.
If you use a stripper, apply thin coats with a paintbrush and work in small areas. Use a plastic putty knife to loosen the paint after it bubbles up. Metal knives can leave deep gouges and it will be hard to hide them in the coaming. It wouldn’t be a bad idea to keep a garden hose handy in case you get the stripper on your skin (it burns!) or in the event that it starts to melt your coaming.
Okay, so you’re ready to prime and paint the coaming. I use a compressor-driven spray gun, but here too, you have options.
One company makes a device (and I can’t think of the name at the moment) that is a jar with an aerosol canister that screws onto the top and essentially, turns any paint into a spray paint. You can achieve excellent results with this. It cost about $9.00 for the jar and two canisters and you can pick one up at Lowes or Home Depot (I will think of the name of this device and revise this paragraph later). You will need to thin the paint in order for it to flow through the canister. 5% thinner by volume is a safe bet.
Painting the coaming using a roller is not very feasible since it is relatively small and has odd angles. You’re better off brushing. To get the best results from brushing, thin the paint to the maximum manufacturer's recommendation (usually 10-12% by volume) and use a good quality brush. I do not like foam brushes because they tend to leave bubbles behind and a brush stroke is easier to hide than a bubble.
Brush strokes will show through in your finish. You can hide them by sanding in-between coats with a 280 grit or higher sandpaper, then painting another coat.
Here is the painting procedure I used on the coaming of 39255 (brushers will get good results following the same methods): Sand with 120 grit until chalky. Wipe down with acetone. Sand any missed spots. Wipe down again if necessary. Spray the first coat of primer. Sand entire coaming with 200 grit to smooth it out. Spray a second coat of primer. Sand entire coaming with 250 grit to smooth it out. Spray the first topcoat (I thin this coat very little, 2% or 3%). Sand with a 280 grit. Spray the second coat (thinned as much as 10%). If necessary, sand with a 400 grit or finishing wool. and spray a third and final coat.
A note about thinning: The amount of thinner to use varies by region and time of year. I live in the hot, humid south so extra thinner is necessary. Read the paint manufacturers recommendations before starting your project.
When reinstalling the coaming, you can use the plastic drywall anchors here as well. Follow the same guidelines that are in “Hardware Removal.”
I always put a small bead of 5200 around the hole for the screw. This prevents water from getting through the deck
