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Your boat's topsides can look like new again with a fresh topside paint job.
Painting the topsides and deck of your boat with a quality marine paint can make it shine like new, helping it do one of the most important jobs of a boat: make you smile! It's fun to look at a good looking, shiny boat while preparing for a day of fun on the water, and easier to clean at the end of the day. So how do you get from your chalky gelcoat or old paint to a yacht that appears new in the color of your choice? Paint it! Marine paints like Awlgrip, Imron, and Interlux Perfection, Toplac or Brightside, Pettit Easypoxy and others can all give you a durable, smooth finish that will last for years with proper care.
Topsides and Deck Repairs
If there are scratches or chips or other irregularities in the gelcoat or paint of your boat, before painting is the time to make them disappear. To grind out blemishes in fiberglass boats and bevel the edges, you will need a multi-tool such as the Dremel multi-tool. After grinding your way back to undamaged material, clean dust with a Shop Vac or air pressure blast, then wipe away contaminants with a solvent such as alcohol, acetone, or Interlux 202. Work filler into the damaged area with a putty knife, then smooth the top just proud of the surrounding surface. Many plastic fillers will serve this purpose, the important thing is not to use one that is too hard.
Epoxy mixed with structural fillers can be extremely difficult to sand back to a flush surface without damaging the surrounding surface, even if using a sanding block. Interlux makes Interprotect Watertite Epoxy Filler and it is easy to use because one part is deep blue and the other white and you just mix it 1:1 until it is sky blue. You can also use West Systems epoxies with 407 microballoon filler or 410 microlight, which is lightweight to help prevent sagging in large areas and is easy to sand. If you use West System 406 colloidal silicon filler or any lower number, it will be stronger, but harder to sand fair.
Once the filler cures, wipe any amine blush away with water and a damp micro fiber rag or paper towels and wet sand with a block sander. You can sand faster with a rotary sander/polisher or orbital finishing sander, but be careful! It is easy to damage the surrounding surface, and if you did a good job applying a sandable filler, a block with some 220 or 300 grit waterproof sandpaper should wet sand it smooth quickly without doing additional damage. Once it looks smooth to your eyes, feel the repair with your fingertips and put a ruler across it if possible to make sure it is flush with the surrounding surface. A slight bump or depression will be very apparent when you are done painting, so take the time to fair any repairs completely. If working up in corners where a sanding block or power sander can't go, try a fine grit sanding sponge.
Primer and Paint Selection
The quality and durability of all the modern yacht paints is very good, giving years of color and shine and resisting scratching, staining, and fuel or chemical spills of many kinds. If you buy a low end yacht enamel and put it on a tired looking boat, it will look great! So why would anyone buy those expensive high end marine paints? What is so special about Awlgrip, anyway?
The fundamental answer is that the highest quality paints last longer, hold color better, resist abrasion and fading better, and are easier to clean and shine. The middle of the road paints do all those things pretty well, and the cheapest boat paints do a decent job, but won't hold up as well. If you look at the cost per year, they all cost similar amounts. How often do you want to repaint your boat?
Polyester Polyurethane Boat Paints
The longest lasting yacht paints are the two component polyester linear polyurethane (LPU) two stage paints such as Awlgrip, Alexseal, Sterling U-series, Interspray 900, Interlux Perfection and others. These paints form a hard, shiny exterior skin, like a clear coat, that makes them durable and easy to clean. They resist scratching and should generally be cleaned only with soap and water using a soft brush, and polished and shined only using the manufacturer's recommended products. Rubbing compound can remove the protective shell, as can high speed polishing with a machine. Just clean it, apply protective carnauba wax or Nu Finish twice a year, and it will last at least ten years in the tropics, longer up north. Note that the solvents used in two pack polyurethane paints can destroy the one part paints, so one part paints must be removed before applying a two part paint. If you are not sure what kind of paint is on your boat, you can test whether the two part paint you want to use can be safely applied over it by soaking a rag in reducing solvent and taping it to the hull in an inconspicuous place. If the paint gets soft within 24 hours, it is a one part polyurethane paint and must be completely removed before applying two part marine paint. If a two part polyurethane paint is scratched, repair will involve blending the hard surface of the existing paint with the repair coats, a job that will challenge even professional painters.
Acrylic Polyurethane Boat Paints
The one part acrylic polyurethane marine paints such as AwlCraft 2000, Interlux Toplac and Brightside, Pettit Easypoxy, Sterling 68A series and Interspray 800 are not as hard as the polyester based paints, so they can be scratched more easily by dinghies, pilings, fenders or anything else that may rub against a boat's topsides. Dark colors will not last as long in one part acrylic polyurethanes as in two part polyester polyurethanes, especially in tropical climates. Acrylic polyurethanes can be compounded and waxed by machine without the risk of damaging the tough skin of a polyester polyurethane, and repairs are easier to blend. One part paints can be applied over a previous coating of any polyurethane paint, and are somewhat more forgiving of imperfect application conditions or techniques. While one part polyurethane topsides and deck paints are not as durable as two part paints, many boaters get years of service from these paints with occasional polishing and protective wax.
Water Reducible Polyurethane Boat PaintsSystem Three makes WR-LPU Linear Polyurethane Topcoat, a two-part, water based linear polyurethane enamel. This water soluble paint competes with the solvent based paints in glossy color and durability, but you can thin it and clean up with water.
Alkyd Enamel Boat Paints
The oil based alkyd enamel boat paints were great for topsides and decks before polyurethane paints became available, and some still use them for their ease of application, compatibility with wood hulls, and low price. You can get a good finish from an alkyd enamel paint, but a polyurethane will perform better for exterior applications, so alkyd enamels are used to paint interior spaces in boats.
Special Purpose Boat Paints
There are various special purpose paints such as Interlux Bilgekote for bilges, Pettit mildew-resistant interior yacht paint, clearcoats with UV blockers, as well as flatteners, non-skid compounds and other special additives for different purposes on boats. If you have in mind using a special paint for a bootstripe or cove stripe, be sure that it is compatible with your topsides paint choice.
Topsides and Deck Surface Prep
The amount of surface preparation needed before painting your boat will depend on the type and condition of the existing surface and on the paint you have chosen. If there are ripples or bumps in the surface, they will be more conspicuous after painting, and if gelcoat or old paint is oxidized and porous, it may be impossible to put a really shiny surface on it. Polyurethane topcoats are very thin and very shiny, and will accentuate flaws and show spots that are not fair, so if you are applying the paint to anything except compatible paint or gelcoat in good condition, it is a good idea to fair and prime before painting. If significant fairing is required, use a fairing putty or high build primer coating for easy sanding, but if you already have an acceptably smooth surface you can prime with Awlgrip 545, Pettit Vivie Epoxy Primer, Interprotect 2000, or whatever primer is recommended for the paint you are using. Pay attention to the recommended curing times for recoating and sanding and work your way up to the finest grit sandpaper allowed for the paint. Note that some kinds of paint are not compatible with non-clogging sandpaper, which can leave residue that interferes with bonding.
If you do not have to use primer for your intended application, just solvent wash the hull to remove any wax, oil, silicon or other contaminants left behind by past polishing. Interlux Fiberglass Solvent Wash 202 or similar products should be used to soak a clean rag and the hull wiped top to bottom, frequently exposing a fresh section of the rag, then wiping away excess solvent with a separate clean rag. Warning: some shop rags have detergents and polishing rags may have silicon in them. If in doubt, run them through the washing machine with no detergent. It is important to remove all contaminants before sanding, so you don't grind them into pores in the surface and create bonding problems for the paint later, so don't skimp on the rags!
Once the surface is completely clean, sand and sand some more, removing sanding dust with each pass using a shop vac, clean rags and the manufacturer's recommended solvents and tack cloths. Be advised that all tack cloths are not created equal, and the wrong kind can do more harm than good, so the safe choice is to get them along with your paint, reducer, and other additives and supplies from one manufacturer. How smooth and uniform does the surface need to be? To give you an idea, later on we will get to practicing paint application on a sheet of glass. You should always wear protective clothing when working with these products, but in the late stages of preparation, pay particular attention to your clothes and natural oils on hands and feet as a potential source of contamination. Do not touch the boat, and if you must walk on a surface to be painted wear clean painter's booties or wrap your socks in masking tape.
Boat Painting Area and Personal Preparation
Before you actually start painting your boat, run through all the steps in your mind, visualizing where you will be, where your paint and supplies will be, and where the job will begin and end. It is important to clean the entire area, removing obstacles and leaving yourself room to work and flat surfaces for materials. If you do not have a climate controlled painting booth, you may want to at least construct simple sun shades using tarps and PVC pipe, wet the ground to control dust, and perhaps burn citronella candles to discourage insects, many of which seem to like wet paint. With the area prepared, mask off the boat. You can create a skirt around the water line, toe rail, or similar areas by running a 2" wide strip of blue masking tape, but only fingering on half of it as you go, then sticking thin painter's plastic or newspaper to the loose part of the tape.
Once the boat is ready, make sure all your materials are on hand and prepared. That means make sure you have the appropriate reducer for your paint, graduated chemical resistant mixing pots, mixing sticks, and extra gloves, rollers, trays, brushes, etc. Open all packages and chemical containers, so you don't have break new seals during painting. Clean new rollers and brushes with solvent to remove any contamination and loose fibers, which should be minimal if you are using quality rollers and good badger hair brushes.
If everything is set up so you can paint without interruption, it is time to protect yourself. Polyurethane paints give off isocyanate and other poisonous vapors, and if you are spraying the paint with an HVLP spray gun, you are supposed to be in a positive pressure suit, with fresh air being supplied to you continuously. Do not spray polyurethane paints unless you are properly fitted with such a device. If you insist on spraying it anyway, or if you are doing a roll and tip application, wear tyvek coveralls and tape up all openings and use a good respirator with organic vapor carbon cartridges and a HEPA filter changed hourly. Those will remove some, but not all, of the harmful vapors. Do not attempt to just stay upwind or hold your breath while you paint a boat; you will be exposed to airborne particles and vapors that are harmful.
Mixing and Testing
Manufacturers recommend certain amounts of reducer depending on the temperature, but the exact "right" amount may be a bit different from their recommended ratio. Factors other than the air temperature affect how the polyurethane paint cures, including sunlight, breeze, humidity, and the application style of the individual painter. To find out the mix that will work best on a given day, have a test subject available. A dinghy, a dock box, or a piece of plywood painted with primer and prepped like the boat can be an invaluable learning platform, and can wind up looking really sharp and matching your boat when you are done.
Roll and Tip Application
Enough has been written on roll and tip application to confuse any sane person who tries to digest it all, and there are videos on YouTube showing different techniques. If you are apprehensive about learning the roll and tip method, first understand how polyurethane paint works and how you need to help it along. You can think of polyurethane paint as a bunch of bungees swimming around in some goo. They want to link to each other, and all of them want to stretch as the goo evaporates away, and if you get it right, you end up with an even layer of interlocked and tightly stretched bungees, creating the glossy shine and inherent durability. To achieve that result, you have to spread them around thin and even, but every time you touch them, you mess up the ongoing interlocking in that area. If you overload the roller, you have to roll a lot to get it thin and even, but if you underload it that can cause additional rolling as well.
Tipping is so called because you do it with just the tip of a clean brush, gently popping any bubbles and leveling out any roller stipple with as few light touches as possible. Keep two tipping brushes going, changing to a clean one that has been soaking in reducer frequently. It is important to get the right reducer mix so that the paint has enough "goo" between the "bungees" to lubricate the whole process of attaching to each other, but not so much as to allow whole areas of bungee mat to slide - that is what creates sags. If you have too little reducer, brush or roller marks will not level themselves out, but if you have too much the paint will sag before it cures and bonds together enough to hold shape. As mentioned, practice on a dinghy or something, and to make sure your application technique can produce a flawless, smooth surface, paint a sheet of glass. If you don't like the mix, it is easy to clean the glass off with thinner and try again.
Most polyurethane paints can be recoated without sanding once they are dry to the touch, but if you wait too long you will have to sand and clean before recoating. Recoating times depend on temperature and the other conditions that affect reducer ratios. If you are too late and the paint is cured, do not try recoating without sanding, as you will only waste valuable time and materials. When you are done with the last coat, leave it alone for as long as you can. Some polyurethane paints do not achieve full hardness for a week, so walking around on a freshly painted deck or putting a boat with freshly painted topsides in a sling can be risky.
Repairing Scratches In Paint
Repairing scratches in two part polyurethane paints like Awlgrip and achieving uninterrupted shine and color across the repair area is a job for professionals. If you attempt it, you will probably end up with a repair that is visible, but at least looks better than a scratch! With the one part paints like Easypoxy or Brightside, it is easier because you can blend and smooth the repair with rubbing compound and a buffer without damaging the paint. As with applying the paint, the key in repairs is to do thin and even coats, each slightly overlapping the previous one. To avoid scratching your paint with fenders that have been covered with barnacles and slime, you might make a set of PVC fender boards.
Cleaning, Compounding, Polishing, Waxing, Poli Glow
To keep your painted topsides and deck looking their best, brush regularly with fresh water using a soft brush and soap only where necessary. Never let soap scum dry, especially in non-skid areas. Some manufacturers have their own cleaning and maintenance products, such as Awlwash, a biodegradable cleaner for Awlgrip and Awlcraft, and Awlcare, a polymer version of an ordinary polish/wax combination, similar to Nu Finish. To shine badly oxidized one part polyurethane paint, you will have to treat it more or less like gelcoat, compounding with a buffer and 3M rubbing compound, following up with a polish using 3M Finesse-It, then wax with 3M Marine Ultra Performance Paste Wax, Collinite, or other good carnauba wax. Be careful of any wax, or any product for that matter, containing silicon. Silicon residue can be very difficult to remove, and can make it impossible to get anything to bond to the contaminated surface.