Choosing the right spray paint
Taking a spray gun to your car is one of the coolest and most satisfying ways to revamp your vehicle and impress your mates. Many car enthusiasts will be itching to get cracking on their re-finish, but before you throw yourself into it, it’s important to be prepared and informed. Misuse or misapplication of car paint can be inconvenient and costly!
If you’re using a paint spray gun on your car, one of the key things you need to do is choose the right spray. Here, we’ll walk you through the basics of how to use a spray gun with the correct product and will talk about other aspects of the process such as primer. It’s worth mentioning at this point that with all the products we’re talking about, the rule of thumb is to use the same brand of product at all stages. Using different layers from different manufacturers often means different formulations and lack of compatibility, which can spell disaster.
Understanding automotive paints
When you go to buy your paint, you’ll probably be bombarded with questions from the sales consultant, so it’s worth having a basic grasp of this area. There are three ingredients that make automotive paints: the carrier agent, the pigment and the binder or resin. The resins in automotive paint are usually made up of one of three elements: urethane, enamel or lacquer. The first two are the best and in general enamel and urethane are common terms for the chemical combination of hydrocarbon polymers that formulates the resins in paints. Lacquer easy to apply and dries up to a glossy finish and is sometimes still used for show cars. However, it’s not recommended by most experts these days. It’s one of the worst pollutants out there because it dries up instead of bonding chemically to the car’s surface during curing period meaning toxic liquid atoms of the paint evaporate into the air.
Once you’ve decided between using urethane or enamel, you’ll also need to decide whether you want to use one part or two part paints. These are also known as 1K or 2K respectively and these distinctions simply refer to whether or not an activator is needed for the paint to dry. Many of these products can be used directly, but some may need a solvent like a thinner so they can go through the paint spray gun properly.
Generally speaking, for basic yellow, black or red colours, you can get away with using single-stage paint, without the additional cost of a clearcoat. For a metallic finish, however, it’s probably advisable to use a basecoat followed by a clearcoat which will provide added protection to your car against chips and scratches.
Primer is vital to prepare your car surface for paint. It’s applied after your vehicle has been sanded and there are a number of primers to choose from, with one of the most popular being self-etch primer, which works for bare steel and aluminium surfaces and uses an acid to adhere to the surface. Another is Epoxy primer, which helps prevent corrosion and works for metal and fibreglass surfaces. Meanwhile, high-build primer helps to remove imperfections on a surface, but it must be sanded before you add a top coat. Urethane primer offers a strong bond with the surface, but is applied in multiple coats and can therefore be time consuming.
After priming, you’ll need to apply base coat in the colour of your choice with a spray paint gun. Again, there are a number of options available and remember, some paints have to be diluted or thinned in order to flow through a spray paint gun with a smooth finish and application. Here are some of your options: Enamel spray paint contains a softer resin and provides a high gloss finish. Urethane spray paint is long lasting and durable, but can be tricky to apply; single-stage paint dries to a glossy finish, while combination paint results in a semi-gloss look.
Clear coat car paint is paint or resin with no pigments. In other words, it's simply a layer of clear resin that is applied over coloured resin. Most vehicles manufactured today have a clear coat finish. After applying the base colour, the final layer is the clear coat, which protects the base coat. Clear coats come with an activator that helps the material to harden and some clear coats harden faster than others. A bigger vehicle may require a slow hardener because that allows you more time to finish painting the car before the surface starts to set; if the clear coat on one part of the vehicle dries faster than another, it results in a layered look. Acrylic spray paints are water-based and need no extra chemicals, such as hardeners. However, they take longer to dry than urethane-based clear coat paints, which resist chipping and scratching longer than acrylic products.