Back in the day choosing a paint for the boat was fairly easy, you went down to the chandlery and picked out a color went home and slapped it on. Well there was little more to it that that but not much. In the past 15 years or so things have moved on at quite a rate and paint is now made by skilled chemists rather than guys in the back of the boatshed.
One of the major advances of interest to the boat owner is the widespread introduction of 2 pack polyurethane paints. These paints manufactured by the likes of Awlgrip, Interlux, Petit and Epifanes offer the ultimate in durability and longevity. Available in an almost infinite variety of colors these paints, which were once the preserve of professional yards, are now available to the DIY boating enthusiast.
Traditionally painting glass fiber was fraught with problems the paint was generally incompatible with the substrate, which tended to flake off and not adhere well. There is still some resistance to painted hulls mostly fueled by old salts that had disappointing results years ago and still think that painting a hull is a bad thing.
Once regarded as something that was done to tart up an old tired hull there are an increasing number of high-end boat builders who now produce their hulls with clear gelcoat and then paint them to owner’s choice later. Hinckley does this and they say that this has several advantages over using a colored gelcoat, imperfections in the lay up are easier to spot, there is less chance of damaging a hull surface before the final fitting out is complete and an owner does not have to decide on a color until the boat is almost ready for delivery.
Two pack paints can be applied in two ways, they can either be sprayed or using the roll and tip method. Spraying is not really a DIY proposition not least because specialized equipment is required beyond the scope of all but the most affluent and determined individual. A spray booth is necessary along with expensive spray guns and respiratory protection. This leads us to the other option of the roller and tip method of application. When done correctly and with care the finished result is almost indistinguishable from spray application and is what I like to call a 15-foot finish. That is from 15 feet away no one will be able to tell the difference.
The deck of this Hinckley Bermuda 40 looks resplendent in a fresh coat of Oyster White.
You can use 2 pack paints almost anywhere but they are probably of most interest to boat owners who use them on their topsides. They are not suitable however for all applications however. Unlike more traditional alkyd paints which have a degree of flexibility, 2 part polyurethanes once cured are very hard and do not have any give and thus are unsuitable for substrates such as wood which move in concert with changes in the atmosphere. Below is an outline of how to go about using 2 part paints for topside painting but also note that they are not suitable for surfaces that will be constantly immersed in water so should not be used below the boot top. However the paints are expensive cost up to 60% than more traditional coatings so you might find it useful to have a go at a smaller project before committing to a full-scale refurb of the boat. A small dinghy could be a good project, as it will give you useful experience with working with the paint before you go on to tackling a larger and more costly project.
For the best results aim to apply 2 pack polyurethanes when the air is still and the temperature is between 50 and 85 degrees. Any hotter and the surface is liable to skin up too fast and any cooler and it will drag, both will result is a poor finish. Avoid applying towards the end of the day when the temperature is falling as this can often result in a loss of gloss retention. At 65 degrees the surface will be tack free within about 3 hours and after 24 will be ready for the next coat. Finally if you are one of the increasing amount of owners that shrink wraps their boat during the winter get the yard to only go as far as the toe rail. You might think that it offers better protection for the paint by going down to the waterline but you would be wrong. Moisture inevitably gets trapped between the wrap and the paint and this will cause bubbling so is best avoided.
How to apply
Two part paints are very expensive so it is important to avoid costly mistakes. The only time that I really got into trouble was when I thought I knew better than the manufacturer and used less thinner then they suggested but the less said about that escapade the better.
Before you go anywhere near your project the first thing to do is read understand and digest the information supplied by the manufacturer. Much information is contained on the can but it is also worth reading the safety data sheets which can be often found at the location where you bought the paint or downloaded from the manufacturers web site.
There will be slight dissimilarities between each of the paint products but in general terms the application and use techniques are common to all two pack paints.
As with any painting the finish will only be as good as the preparation. Get the surface as smooth as possible and you are half way to a great looking paint job. Assuming that you are going to paint the topsides start by washing the boat down with good boat soap, check that it does not contain any silicone, which will react with any paint coatings and prevent them from adhering. I have had good results with Latitude 43 organic boat soap, spray on leave to soak for 15 minutes then rinse off. The other option is to use some of the soft scrub type bathroom cleaners. What we are trying to do at this stage is to clean all contamination from the surface. Whatever product you ultimately use rinse thoroughly and completely with lots of clean water. Any beading up on the surface of the hull means that wax or other contaminants are present.
With the hull clean the boat can be sanded to provide a key for subsequent coatings. I like to use 80 grit paper in a random orbit sander, keep the sander moving to avoid sanding off too much or you could go through the gel coat or at the very least make it very thin unnecessarily. Work methodically and completely making sure that the hull or other surface is universally dull. This process is very dusty so wear old clothes, a suitable dust mask and eye protection. I like to run my fingers lightly over the sanded surface as you can feel imperfection far better than you can see them. Dust off the topsides and as you do put pencil mark circles around any imperfections, dings or gouges that need attention. If major fairing and filling work is required in any area now is the time to mix up some epoxy and micro balloons and trowel this onto the surface with a wide plastic squeegee. If the repairs are minor I like to use Bondo type filler. Filling an d fairing is definitely an acquired art on the one hand you need to apply enough to fill the imperfection but on the other hand not so much that you have a lot of extra sanding to do later. With the filler applied I like to leave the surface for at least 24 hours to allow any filler to cure I then come back to the boat and sand down the surface to feather in the filled areas. Although it can be tempting to use the random orbit sander it is all to easy to take off too much in which case you will have to reapply additional filler. Buy or make up a long sanding board to which you can stick abrasive paper and use this to sand down any filler, it can be hard work but the end result will be far better.
With the surface now hopefully silky smooth we can start to apply paint but first mask off all areas that you don’t wont paint to touch which for most yachts will be along the underside of the toe rail and along the top of the boot top. Dust the boat off thoroughly then wipe the whole area to be coated with the thinners or solvent recommended by the manufacturer changing rags often to avoid moving dirt from one area to another. While min some cases it is possible to proceed directly to topcoats better results will be obtained by applying an epoxy primer. This is mixed following the instructions on the can to the letter. Generally these are two part products a hardener is added to a base, mixed solvent added, mixed again then left to stand or ‘induct’ for 20 minutes to half an hour before application.
The undercoats are applied in the same way as the final topcoats so perfect your technique on this initial coat and the topcoats will go like a breeze. Starting at one end of the boat one painter rolls on a coat of paint while a second painter immediately follows up with a dry brush and ‘tips’ off the surface to relax the orange peel effect left by the roller and further smooth out the paint. The brush should not be dragged through the paint only the lightest of touches are necessary. The work will move quickly but once you stop don’t stop, the last time I did this on a 38 footer two of us got round the boat in a couple of hours fairly easily.
The colored topcoats are applied in exactly the same way and using the same technique but you will notice that they can be noticeably thinner and therefore faster to apply but to achieve full coverage you may need 3 coats sanding between each coat with 400-grit paper.
Safety
Working with 2 part paints does not pose a health hazard providing a few simple common sense rules are followed.
1
Always ready and adhere to manufacturers recommendations for application techniques.
2
Keep a clean work area and do not smoke, drink or eat until you are well away from the painting area and you have washed your hands.
3
Wear protective face and eye protection. Tyvek suits and latex or nitrile gloves will keep paints and solvents off your skin.
4
Don’t spray 2 pack paints unless you have specialist knowledge and the correct equipment.
5
Dispose of unused paint properly allow it to cure before throwing into the trash and never under any circumstances tip it down drains or into watercourses.
How much do I need?
As a rough guide one pint of correctly thinned paint will cover about 75 square feet so from this you should be able to work out the amount of paint that you need. I found that I needed one undercoat and three top coats for the best coverage last time that I used 2 pack paints so work out the square footage to paint multiply by four and that will give you the total surface area that you will eventually have to cover with paint.
The paints are all available either directly from the suppliers or from local stockists such as West Marine. Color charts are available on line but every computer monitor is different and shows color in a differing way so pick from a color card if at all possible to avoid disappointment.
Resources
Paint
Epifanes
800-269-0961
Interlux
800-468-7589
Pettit
800-221-4466
Brushes and rollers
Corona
800-458-3483
The roll and tip method when done correctly produces results to rival spraying. One operator rolls on the paint and another helper follows immediately behind with a dry brush tipping off the paint. This relaxes the paint makes roller marks disappear and smoothes the surface.
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