Aluminum paints are usually vinyl-type products characterized by excellent adhesion to aluminum and metal substrates. Additionally, there is no need to prime these surfaces, reducing the application time and labor costs, and the paint's semi-flat finish provides less drag on boat bottoms than other marine paints. Furthermore, it washes easily and resists oil, gasoline and discoloration for harbor gases.
The main purpose for painting an aluminum boat is for aesthetic appeal. While it may not bother those who use their boats for industrial purposes, many recreational boat owners dislike the dull gray finish of worn aluminum.
Painting an aluminum boat is a double-edged sword. On the one hand, once painted, aluminum does not develop the tough, clear, corrosion-resistant oxide coating that it normally would upon consistent exposure to the water. However, when aluminum is not exposed to moisture, its corrosion clock slows down considerably.
The paint works well and looks good until it is breached. The breach can be microscopic, but still has the same effect. Over time, the paint lifts from the aluminum in some spots, giving it the appearance of bubbles.
A minor downside to aluminum paint is its higher cost. It runs at around $75 per gallon as opposed to the $30 per gallon one would pay for a copper-based marine paint.