Painting Tips

• Always read and follow the manufacturer's instructions and safety precautions.
• Spread plastic on the ground to collect and dispose of paint chips, sanding dust, and drips.
• Never leave bare wood exposed, it will affect your finish.
• Wipe down and sand the surface free of wax coating.
• Previously unpainted hulls must be cleaned with a dewaxing solvent to ensure paint adhesion.
• Optimal painting conditions are when the temperature is 50-80°F and relative humidity is below 65%.
• Apply paint or varnish on a medium temperature, low humidity day for optimum drying and no dripping.
• Several thin coats are better than one thick coat.
• Wear protective clothing, especially for eyes and hands.

Applying Bottom Paint

Preparation required for a successful bottom paint job begins as soon as the hull clears the water.

Clean

Slime and growth are relatively easy to remove while the bottom is still wet, but let the stuff dry and you will have to chisel it off. Fortunately most boat yards pressure wash the bottom as soon as they haul the boat, and many will also knock off hard growth with a long-handled scraper.

Strip

The adhesion of the new paint is only as good as that of the paint under it, so watch for signs of adhesion failure. Anywhere the old paint is flaking or lifting, scrape exposed edges with a knife or small chisel. If the paint zips off, the bottom needs to be stripped.

You may also have to strip the bottom if you are changing paint type. For example, the aggressive solvents in vinyl paints lift other types of bottom paints, so if you are applying vinyl, any non-vinyl paint has to come off. And soft, sloughing paints are a poor undercoat for anything other than a fresh coat of the same.

Using a 2" hook scraper is the stripping method least injurious to both you and the planet, and this is often the easiest method as well. If you decide to use a chemical stripper, be sure it is one formulated for fiberglass; regular strippers will attack the gelcoat.

Sand

When the old paint is in good condition, in general you need only sand it, wash it, tape the waterline, and roll on a fresh coat or two. A grinder loaded with 80-grit disks on a foam pad can quickly prepare a hull for recoating, but it can also chew through the paint and into the laminate in an instant. If you lack experience with this powerful tool; 80-grit paper in a random orbit sander or a finishing sander will do the same job with less risk to the hull. Do not use a belt sander; it is designed to make things flat and that is the effect it will have on your hull.

Many boat yards now prohibit normal power sanding because of the dust it generates. The solution is a shop-vac and a random-orbit sander with a vacuum hose connection. If you don't want to buy a new sander, slip a length of plastic hose over the dust bag mount on your old palm sander and tape the other end into the shop-vac hose. Either rig will capture most of the toxic dust sanding generates-but not all of it. Be sure to wear a tight-fitting respirator-not a paper mask-while sanding. Also wear earplugs to shut out the din of the sander and the vac; you'll save your hearing and find the work much less tiring.

Even if you aren't stripping the bottom, it is good practice to sand away most of the previous application. This avoids a thick build-up that will turn brittle and cause new paint to flake. A different color first coat provides a flag that signals when you have sanded enough.

Bare Fiberglass

A hull that has not been previously painted has mold release wax on the fiberglass that will interfere with paint adhesion unless you remove it. Clean the hull surface thoroughly with dewaxing solvent and plenty of clean rags before you sand; otherwise sanding drags the wax into the scratches and it will be that much harder to remove.

Sand the dewaxed hull lightly with 80-grit paper before applying the first coat of paint-the flag coat-which should be a different color from the top coat(s).

Stir

Run the can in a paint shaker for at least 5 minutes to get the copper and the pigment evenly distributed throughout the paint. Let it run for 10 or 15 minutes if it's been on the shelf a while. In the absence of a shaker, pour half the paint into a mixing bucket so you can mix the remaining half vigorously without sloshing paint onto the ground. Keep dredging up the copper off the bottom of the can until the bottom feels clean to the touch of your paddle. Slowly stir in what you poured off until the paint is uniform in color and consistency.

Roll

Roll the paint onto the hull using a short-nap roller cover. An extension for the handle will make painting the keel easier and keep you clear of the inevitable droplets the roller will sling. Wear sleeves and gloves to keep the paint off your skin.

Fill your paint tray with paint. Dip your roller, unload it on the tray slope, and roll it up and down on the hull, i.e. from waterline to keel. Work fast as many bottom paints dry quickly. Each time you refill the paint tray, first stir the paint in the can to keep the copper in suspension.

By the time you work all the way around the hull, many bottom paints will be dry enough to overcoat. Check the specifications on the paint you are using. A second coat lengthens the life of almost any bottom paint; copolymers benefit from 3 or 4 coats. No sanding or other prep is needed between coats. Save some paint for the areas under the stand or cradle pads.

Let bottom paint dry at least overnight before you put masking tape on it to paint the bootstripe. Get hard bottom paint into the water within the time specified on the label.

Types of Bottom Paint

Copper Antifouling Paints

The copper content, usually given as a percentage, is not the only factor in a paint's effectiveness. Binder/ release, surface smoothness, copper as a percent of the dry film, and film thickness also contribute. There are essentially two types of copper antifouling paint-leaching paints and copolymers, also known as ablative paints. Leaching paints with twice as much copper as copolymers are similar in effectiveness because they leach high levels of copper initially and gradually taper off. Copolymers, which frequently state copper content as a percentage of volume solids, are referring to the copper that's left in the film once the solvents evaporate. Copolymer copper paints tend to release copper at a constant rate over time, rather than in a tapering pattern. And they do not release copper when out of the water, which may lengthen the time between bottom paintings.

Waterbased Antifoulings

These contain little or no solvent and therefore have fewer VOCs (Volatile Organic Compounds). Thinning is generally done with tap water. Waterbased antifoulings are EPA approved, but still contain toxins, so empty containers and clean-up residue must be disposed of properly.

Copper Thiocyonate

Copper thiocyonate is a derivative of cuprous oxide, and is generally used over aluminum by professionals and do-it-yourselfers as a replacement for tin-based antifouling. While antifouling paints with copper thiocyonate will not cause corrosion, it is still advisable to apply a primer to any underwater metal to increase adhesion and reduce the risk of electrolysis.

Tin Paints

Tin paints, which do not cause electrolysis, may still be applied to aluminum boats under federal regulation if they meet release rate standards, and are applied by a trained and certified commercial painter. Licenses, usually issued by each state's department of agriculture, govern both the sale and application of this paint and often prohibit purchase by non-licensed persons. For this reason, BoatU.S. does not stock or order tin-based bottom paint.

Regulating Volatile Organic Compounds (VOCs)

Solvents or thinners are used to liquefy paints. When solvents evaporate they become volatile organic compounds (VOCs). State and federal agencies regulate VOCs because of their detrimental effect on the ozone layer. As a result, sales restrictions may apply in some locations.

Special Shipping Restrictions on Hazardous Materials

Shipments of flammable or hazardous materials such as certain paints, varnishes, flares, fire extinguishers and other compressed gases are regulated by the Department of Transportation. Please note the following when ordering these items from our catalog:

• UPS Ground is available for all hazardous items shipping in the continental U.S. except for certain safety signaling devices and stove alcohol.
• UPS Ground delivery is not available in the U.S.V.I., Hawaii, Alaska, or Puerto Rico.
• Federal Express is available for all hazardous shipments except gallon containers of paint, resin or other hazardous liquid. Priority Overnight is the only service available. Hazardous shipments are not allowed to the U.S.V.I. Hazardous shipments can go to most areas of Alaska and Hawaii-Call for details.
• Quart sized products can be shipped UPS Ground, Federal Express, or Parcel Post.
• BoatU.S. cannot ship hazardous items to APOs, FPOs or other foreign addresses.
• Some UPS and FedEx shipments may be subject to a hazardous material surcharge. See order form for details.
• Hazardous items subject to surcharges are distinguished in the catalog by the hazardous symbol above.

Due to legal resrictions, some paints may not be available in California or Michigan.