Durall Boat Bottom Paint

Instructions for applying boat bottom paint

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1. Setting up to paint your boat bottom

You can paint your hull safely and easily when on your trailer, cradle, or blocked storage system. Support points should be  touched-in just before launching. Just shift the boat, sand lightly, touch-in, and wait 10 to 30 minutes before launching. Our copper nonstick and our clear nonstick paints dry in 10 minutes or less. Our urethane nonstick paints dry in 30 minutes.

2. Pressure washing your boat bottom

The key to bottom painting is adhesion. To allow your bottom paint to adhere well, your bottom surface must be hard, clean, and have a slight texture. A once-over with a 3500 psi pressure washer or better is the first step. If the existing paint is soft, where your fingernail can dig into it, you will need to bring it down to a hard finish. Using a spiraling tip on your pressure washer that applies a round stream will give you the most pressure at the hull surface. These spiraling tips can peal off soft oblate finishes to a surface that will not scratch with your fingernail. When you get there, you can quickly sand the bottom.

3. Prepping your boat for bottom paint

Sanding your boat bottom with an 80- to 100-grit sponge or palm sander is a quick and easy way to remove remaining contaminants and wax, while leaving a microscopic texture for your new boat bottom paint to adhere to. Dry sanding works well but sometimes tends to clog the grit surface requiring changes of sanding paper or sponges. Wet sanding often keeps sanding paper or sponges open to continue their work. Use whichever method is easiest. While sanding, extra time can help smooth out gel coat repairs, burs, and scratches.

4. Repairing irregularities in your bottom

You may use glazing compound over your old paint or between new coats to fill and smooth the hull before applying your new boat bottom paint. You should lightly sand, and wipe dust free, any surface before coating. Touching in or striping newly glazed areas is recommended before the final coat is applied. This will help prevent show through, by (in effect) adding an extra coat over the repaired areas.

5. Taping your waterline or striping

Using a fresh role of blue masking tape will save a lot of time and effort. Once the hull is dry, you can pull the tape from stem to stern. Use a chalk line if you wish or follow your old water line. To stripe, you can use striping tape or just pull two tapes along your hull and brush your color in from the tap to the center. Whenever you use tape, it is best to pull it off before the bottom paint dries or you may glue it to the hull. Have a little thinner available before the bottom paint dries to remove drips.

6. Mixing bottom paint

  1. The clear nonstick boat bottom paint is ready to use but should be stirred. It will not yellow over time. The clear can go over any surface without changing the underlying color. Most boat waxes are water based and will wash off with time as they dissolve in water. Smooth Sailing clear nonstick can be used both below and above water to protect boat hulls in place of on going waxing.
  2. The copper nonstick boat bottom paint comes with the copper component in a separate pouch. This is to prevent the copper grains from settling in the can before application. You need to add the copper powder into the clear nonstick coating and stir until fully mixed (about 1 minute) before application. The copper will stay suspended for about 24 hours but mixing occasionally is a good idea.
  3. Smooth Sailing urethane nonstick coating is a two-part mix. The catalyst is mixed with the color component at a 3 to 1 ratio by volume. Once mixed, the coating should be applied within 2 hours, as it will set up in the can within 18 hours.

7. Clear and copper coating characteristics

The nonstick clear and copper have almost no odor and dry in 10 minutes or less on the hull. The boat can be placed in the water immediately so areas that had pads or rollers can be coated as the boat is moved to the water.

8. Characteristics of nonstick urethane

Smooth Sailing urethane comes in popular colors and lasts up to 11 years without recoating. While our urethane contains no copper as a deterrent to organisms, it does have an antifouling agent and a very low drag coefficient so most organisms slide off at speeds of 15 to 20 knots. Urethane does have some odor. When applying in closed spaces, a vapor mask is recommended. In open air, no mask is normally required. The product starts to dry in about 10 minutes and is hard enough for launching in about 30 minutes in warm weather. Application should be done in temperatures of 55 degrees F or higher.

9. Application of coating

The first coat should be sprayed or applied with a 9-inch mohair roller and/or brush. The second coat can go on any time after the first coat is hard, but waiting about 15 minutes for the copper and clear and about one hour for the urethanes is recommended. Avoid introducing air into the urethane to avoid bubbles. If bubbles occur some light sanding may be needed and a recoat of the bubbled area.

10. Tricks for application

Putting your mixed boat bottom paint into a squeeze bottle, such as a clean dish soap bottle or a squirt type drinking bottle, can help keep the solvents used from evaporating. The less air exposure your mixed paint has the easier it will flow over the boat bottom surface. Going just one direction during your application helps to avoid bubbles. Starting low and moving up helps limit drips. Using a threaded handle on your roller frame allows you to reach center areas without getting dripped on. Taping your brush to a long handle with duct tape helps reach spots that your trailer or cradle tends to keep you from.

11. If you want to strip off your old finish

Often just pressure washing with the full force of at least a 3500 psi washer with a spiral tip that can apply a round stream will remove some boat bottom paints and contaminants. If you wish to remove the entire finish, you may sand to the starting finish material. You can often chemically remove your bottom paint by applying a methylene chloride type of paint stripper. (Durall makes a good one.) Chemical stripping requires plenty of ventilation, and a VOC vapor mask should be used. Often, using a 4-inch, long-handled scraper as you do your cleaning prep or paint stripping can remove all the previous finish that is about to come off the hull. Finishing with a degreaser and pressure washer with a spiral tip should complete the paint removal. (Durall also makes a good degreaser.)

Smooth Sailing, Inc.  |  102 North Street  |  Hudson WI 54016
service@boat-bottom-paint.com   |  www.boat-bottom-paint.com
Telephone: 612-226-5200