Vinyl Paint Mixing

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Application Thickness.

TB-43-0144 Painting of Watercraft Manual

Spray Gun Adjustments

corrosion products should be removed, and surfaces prepared as specified above. Oil and grease may be

removed with suitable solvents.

(b) To avoid after-corrosion or surface contamination, each shift shall clean only the areas that can

be coated in the same shift. All cleaned surfaces shall be coated as soon as practical, including those that

were cleaned of oil and grease as well as corrosive products.

d. Vinyl Paint Mixing. Vinyl paints are best mixed by using a mechanical shaker or high-speed stirrer.

Mixing is very important because the copper pigment in antifouling paint settles to the bottom of the

containers during storage. All of the pigment must be thoroughly dispersed in the paint to achieve

optimum antifouling properties. After agitation, the paint should be examined with a hand paddle to be

sure that the contents of the container are properly mixed. The paint should be restirred as necessary to

keep the pigment in suspension.

e. Vinyl Paint Application. Vinyl paints may be applied through any paint application method. They

should not be applied over conventional paint films because of the softening effect of the ketone

ingredient used in vinyl paints. When vinyl antifouling paints are applied over cured epoxy paints, a mist

coat of the epoxy paint must be applied before the vinyl paint to assure adhesion. Depending upon the

thickness of the wet film and weather conditions, vinyl paints may be recoated within 1 hour. A minimum

drying period of 24 hours, preferably longer, is necessary between the final coats and undocking to

ensure solvent release.

(1) Hot and Airless Spray Application. Hot and airless sprays require special techniques that should

be developed by the shipyard.

(2) Conventional Spray Application. The actual application of vinyl coatings by spray requires more

technique and a better understanding of spray equipment than is usually exercised with other types of

finishes. Since vinyl paints are comparatively low in non-volatile film-forming materials, the operator must

make slow steady passes with the spray gun. The speed of the passes has a direct relation to the DFT,

which, in turn, influences the ultimate performance of the system.

(3) There are many variables in spraying vinyl paints, some of which are influenced by the painter's

experience. These factors include: atomizing, fluid pressures, and the necessity for thinning the paints.

These factors are, in turn, influenced by:

(a) Paint viscosity.

(b) Ambient temperature during application.

(d) Length and diameter of the paint lines.

(e) Height between paint pot and spray gun.

(4) Ensure that the spray equipment is clean, in good working order, and correctly assembled.

Obviously worn parts, particularly the air cap, fluid tip, and needle, shall be replaced. These parts shall be

examined for clogging and shall be cleaned during the application whenever it is apparent that the gun is

spraying improperly.

(5) Vinyl Paint Thinner. Methyl isobutyl ketene, or a 50-50 mixture of methyl isobutyl ketone and

xylene, should be used for thinning paints when required to obtain a suitable spray pattern or when

cleaning the equipment. A mixture of l/2 to 1 gallon of ketone to 5 gallons of paint has been found to

sufficiently thin most vinyl paints.