You should always wear a respirator when you are painting.
It's cool to paint your own car, but talking to the guy at the paint store may cause you to reconsider your plan. Enamel? Urethane? Two-part? Single-stage? The terminology alone can send many people right back out the door. We'll help you sort through some of the confusion with a parts-store cheat sheet, share some of our knowledge based on personal experience, talk to a couple of pro painters, and illustrate some of the latest trendy ideas that even the novice can pull off.
The Basics
All paints are made up of three ingredients: binder, pigment, and a carrier agent. Pigment, or tint, is self-explanatory-it's the color you see. Binder is often referred to as resin, and it can be helpful to think of it like tree sap, that thick, sticky hydrocarbon liquid that hardens when exposed to air. And carrier agent refers to the solution that the resin is suspended in. It keeps the binder in liquid form until it is applied, at which time it either evaporates or chemically bonds to the surface of the car.
Did you know that GM was still painting its cars with lacquer into the late '80s? This '86 Caprice was sporting its OE Seafoam Green lacquer. Look at how badly the paint is cracked along the top of the doorsill. The whole car needed to be stripped to bare metal.
Automotive paint resins are usually one of the following three chemical compounds: lacquer, enamel, or urethane. Lacquer is difficult to find (and illegal to spray) in pollution-controlled areas of the country, but it's worth mentioning because you'll still hear guys waxing poetic about hand-rubbed lacquer. The appeal of lacquer is that it's easy to spray, and it dries to a smooth, glossy show-car finish. Compared to today's paints, though, lacquer is crap because it needs a lot of maintenance in the form of waxing and buffing, and it becomes brittle with age. Exposure to sunlight accelerates its aging, and if not religiously maintained, lacquer will be cracked and chalky in a few years. It's also the gross polluter of the paint world because lacquer cures by drying rather than chemically bonding to the car. In other words, the liquid portions of the paint evaporate, leaving the tinted resin, or color coat, behind. Those liquid portions are highly toxic solvents like toluene that don't react well with Green Party members. So lacquer is great for a show car that spends 90 percent of its life in a climate-controlled garage, but not practical on a driver.
That leaves enamels and urethanes as the remaining options. To confound novice painters, there are many varieties of these resins. There are synthetic, acrylic, and even hybrids of the two (urethane enamel, for example). But in general, urethane and enamel refer to the chemistry of the hydrocarbon polymers that form the resin of the paint. And that chemistry affects the look and durability of the finish, how it is sprayed on the car, and, of course, how much it costs.
The best paint in the world is guaranteed to look bad on a car that wasn't prepped correctly. We used a quality primer-sealer and wiped the car thoroughly with wax and grease remover and a tack cloth first before spraying any color.
Seeking clarity, we spoke to some industry insiders about the differences between these two compounds, and all were in agreement: Enamels are a softer resin, usually dry to a glossy finish, and are less expensive than urethanes. Urethanes are generally a more durable product but can be more difficult to spray. Most new cars are painted with a type of urethane, and most collision repair shops use urethane to repair damage. Maaco, Earl Scheib, and 1-Day Paint often use enamels for their economy.
Single-stage, Two-component
Once you've chosen the type of paint you'll be spraying, you may have a couple more options: One- or two-part? Single-stage or basecoat/ clearcoat?
One- or two-part (or -component) is also referred to as 1K or 2K, and it simply means that the paint either does or does not require an activator to dry. One-part products are ready to spray-they may need to be diluted with a solvent, sometimes referred to as a reducer or thinner, to flow through the spray gun properly, but they will dry on their own. Usually one-part paints are not used to repaint an entire car. Nearly all aerosol-can paints are one-part, as are One Shot pinstriping enamels and specialty products like Eastwood's Chassis Black.