Paints, Primers, Stains and Spray Enamels

Aerosol or can: choosing the form and the finish

Spray cans are convenient for small metal parts, railings, tools and touch-ups, while one-gallon cans suit floors, walls and larger surfaces. A rust-preventive enamel can go directly on sound metal, and some primers are made for specific problems, such as blocking mold or stains. Hybrid urethane-latex-epoxy products, as listed here, come in one-gallon cans; check the label for the surfaces they are approved for.

Color and sheen are chosen separately. Gloss is hard and easy to wash, flat hides imperfections, and satin sits in between. Safety yellow, white, gray and black are common utility colors, and line-marking paint is sold in aerosol cans designed for marking lines on ground and floors. Coverage is printed on the can, per can or per gallon, for a single coat.

Surface prep, recoat windows and ventilation

The finish is only as good as the surface. Remove rust and loose paint, clean off grease, and let the surface dry; glossy surfaces should be scuffed lightly. Check the temperature range on the label, commonly in the 50 to 90 degree Fahrenheit band, because cold or humid conditions slow drying and weaken adhesion. Shake aerosol cans thoroughly and spray in thin, even coats from a steady distance.

Respect the drying stages. Dry to touch comes first, then a recoat window, and finally full cure, which can take days; a coating recoated too early can wrinkle, and one recoated too late may need sanding for adhesion. Work in a ventilated space, wear a respirator suited to solvents, and keep aerosols away from heat and flame. Keep leftover paint sealed and upright.

Questions about Paints, Primers, Stains and Spray Enamels

Do I need primer under spray enamel?

Rust-preventive enamels are made to go straight on sound, clean metal. Bare wood, heavily rusted metal, glossy surfaces and big color changes still benefit from primer, which improves adhesion and uniform color. Follow the label, and test on a hidden spot if unsure.

What is the difference between gloss, satin and flat finishes?

Gloss reflects the most light, forms the hardest surface and wipes clean easily, but shows flaws. Flat reflects almost none and hides flaws, but marks more easily. Satin and semi-gloss are in between. High-traffic surfaces and metal usually suit gloss or semi-gloss.

How long before I can use or recoat a painted surface?

Times are on the label and depend on temperature and humidity. Dry to touch can be under an hour, recoating often falls within a set window or after several hours, and full cure may take days. Do not load painted floors or benches until fully cured.