Boat Paint and Marine Painting

Topside Painting

As with most painting projects, proper preparation of the surface is the key. Once the prep work is done, the painting itself should proceed quickly and easily.

Preparing Your Boat for Topside Paint

The secret here is that the surface should feel smooth to your ungloved hand. Additional coats of paint will not fill in any surface imperfections or improve an improperly prepared surface. Get yourself plenty of fine-grit sandpaper, paint thinner, solvent, putties, and sealers, and get to work smoothing out the surface.

Selecting the Right Paint for Your Boat

There are 3 basic types of paint commonly used on boats: one-part polyurethane, two-part polyurethane, and alkyd enamel.

• One-Part Polyurethane:
  This is the most common paint used on boat topsides, even though it is not quite as durable or as hard as two-part polyurethane, it is relatively easy to achieve near-professional results with either a brush or a paint roller, and it requires less surface preparation than two-part polyurethane.
• Two-Part Polyurethane:
  Two-part polyurethane marine paints are the most durable, hardest, highest-gloss paint available, but painting your boat with two-part polyurethane paint requires more surface preparation and greater skill skills than one-part paints. Additionally, two-part polyurethanes are more toxic, particularly when sprayed on, and so require greater care in the application process. Manufacturers of these paints recommend its use by professionals — if you decide to do it yourself anyway, be sure to follow the manufacturer's instructions to the letter. Some two-part polyurethanes can lift oil-based paints, so avoid using it on a boat that already has an oil-based paint.
• Alkyd Enamel:
  This oil-based paint is the easiest for beginners to apply with a brush, is easier to apply than polyurethane paints, and is more compatible with other underlying paints. It also tends to be more economical. The downside to alkyd enamel paints is that it will generally fade faster and doesn't have the same gloss when dry as the polyurethane paints. The oils in alkyd enamel paints are compatible with the natural oils in wood, so it's well suited for use on wood plank boats.

Applying the Paint

• Read the instructions thoroughly. Then read them again. Be sure you understand the steps in the process, and how the paint should be handled and applied.
• Use high-quality brushes and rollers.
• Pay attention to the temperature where you'll be painting, and heed the manufacturer's instructions about the appropriate temperature range for applying the paint, usually around 50 to 80 degrees fahrenheit. Be aware that high humidity can slow the drying time between coats.
• Multiple thin coats of paint are preferable to fewer thick coats.
• Use a tack rag to clean the surface immediately before painting.
• Using your roller or brush, spread the paint quickly and evenly in one direction and with a uniform thickness.
• Allow sufficient drying time between coats.
• Clean and sand all surfaces between coats. Remove oil and dirt residues, then sanding to smooth the surface, help fill small defects, and prepare the surface for the next coat to adhere evenly. Use a fine-grit sanding paper, and be careful not to sand with too much pressure.
• If spraying, follow the manufacturer's instructions carefully. Spraying is usually only done by professionals with the proper equipment.
• Enamel paints should be stirred, not shaken.
• Bottom paints need to be shaken to stir up the heavier aggregate that settles on the bottom.

Boat Painting and Safety

The chemical fumes given off by marine paint, acetone, and other materials is dangerous. Use proper safety precautions to protect yourself.

• Work in the well-ventilated area. Use fans to assist with air circulation if needed, but be sure not to aim the fans directly at the work area.
• Wear eye protection, disposable gloves, coveralls, and vapor-absorbing filters, particularly when handling toxic chemicals.
• If you get solvents or other chemicals on your skin, flush thoroughly with water immediately.
• Dispose of used materials safely. Ask your boatyard or marine if they have a chemical disposal program, or check with your local environmental office for proper disposal procedures.
• Keep all chemicals away from sparks and open flames.
• Wash off all sanding residue and solvents immediately after completing the painting.