Understanding Automotive Paints
There are a fair few different types of paints used in the automotive world, and the range of choices goes hand in hand with their complexity and price range. There’s a little bit to understand about the different types of paint as well as their suitability for particular applications so it’s good to get an idea of what’s what before jumping into any sort of paint job yourself. Let’s take a look at the choices you have.
The first thing to understand is that most automotive paint is broken down into two main categories according to the number of “stages” involved in the paint job. This refers to the different coats that need to go into making the final paint job look good and provide the right level of wear resistance. It’s important to note that it’s “different coats” that is talked about here, and not just the number of coats in total - and also that this doesn’t actually include prep coats such as anti-corrosion undercoats.
Single Stage - This group is usually limited to enamels and urethanes (we’ll explain these later) where a single can of paint contains the base colour, as well as the shiny topcoat mixed in together. Usually when applying single stage paints, you’ll apply an initial half coat that’s thinner and lighter, and then a couple of proper coats, without the need for any sort of clear coat over the top.
Some of the more specialty paints, such as powder coating and epoxy paints can be applied as single stage paints, but it will vary by paint and application.
Two Stage - or base and top coat finishes, require you to apply an initial base coat (or a few) of the colour you want, and then a protective and shiny clear coat over the top. These coats will be done over the top of a primer usually, and the number of coats applied in each stage will vary depending upon the desired finish.
Of course, like everything, there are exceptions to the rule - such as candy paints or other special ways of applying coats in order to achieve unique looks - but for the sake of simplicity, these two main categories are where you should start.
Most beginners should start with single stage paints as the application is far easier, you don’t need to juggle spray guns or multiple cans, and you can usually achieve a fairly balanced finish to the paint without much experience. Now let’s look at the main types of paint.
There are 3 basic types of car paint; Lacquer, Enamel and Urethane. However, what paint belongs in what category, and even the definitions themselves are actually fairly blurred due to the massive variety in compounds and applications these days.
What is Lacquer Paint?
These are quite a dated paint choice and are not used on new vehicles. If you are restoring an older car you might choose lacquer paint to match the original finish, but realistically, urethane paints can usually achieve the same look while also providing far better surface protection. Lacquer paints also require a larger amount of hand work in order to achieve the same sort of shine as newer paint types.
What is Enamel Paint?
Enamel paints are often broken down into two additional categories - Synthetic Enamel, and Acrylic Enamel Synthetic Enamel should be thought of as a Utility Grade Paint. It’s usually only available in basic premixed colours, and is often used in situations where the paint doesn’t need to last too long, or won’t be exposed to a hard life. Synthetic Enamel is a single stage paint and doesn’t require any hardener to be added nor does it need to be baked on. Acrylic Enamel paints are often used with a hardener, which will increase their durability and decrease their drying time. While it usually comes in premixed colours, you can usually get acrylic enamel paint mixed to match your car’s colour. Acrylic enamel paint is available as either a single stage or a two stage paint, and will often need to be baked onto the car in order to provide a hard, long-lasting finish.
What is Urethane Paint?
Urethane finishes are probably the best commercially available paint choice currently, and are available in any colour you could require. Because it’s available in any colour, and can be mixed up to suit your requirements, colour matching urethane paint is a great way to ensure that touch-ups or partial resprays match paint that’s likely faded due to sun damage. Appropriately, urethane paint is also far more resistant to UV damage than other, older paints too. Urethane finishes always require the use of a hardener, which makes them quick to dry and very strong. The downside however is that mixed pain needs to be used or disposed of fairly rapidly, and that hardener is super toxic. While it’s important that safety gear such as respirators and goggles be used with ALL paint (we’ll cover this a little later) - it is absolutely necessary with urethane paints, as prolonged exposure to their fumes can be deadly.
What is Epoxy Paint?
These aren’t usually used on cars but are great for vehicles (or parts) that require an extremely durable finish. These paints are usually sold as rust prevention or protection from acids or other corrosive substances. Most epoxy paints are incredibly toxic, so appropriate protection should be used, or you’ll probably die.
What is Powder Coating?
This is a special process that requires baking a kind of plastic dust onto statically charged metal. It’s not used on exterior finishes usually (it’d be a massive job!) but Is very commonly used on small parts that need a durable finish, or on wheels and the like. Primers - Also called undercoats, primer is designed to provide proper adhesion of the paint job to the painted surface, as well as protect from corrosion and increase the durability of the paint job. Certain types of primer, namely Primer Fillers and Surfacers will provide “build up” which will allow for excess material that can be sanded down to provide a smooth and even surface for paint.
What is a Rust Converter?
These do what their name suggests. They are a type of primer that converts the iron oxide III of corroding steel into a more stable form - usually ferric tannate, that can be painted over without risk of further rust occurring.
What is Underbody Paint?
These are usually paints that are mixed in with special bituminous goo. They provide great resistance to moisture, as well as offering protection from impacts such as stone chips, and adding a sound-deadening effect to the painted surface. They can be brushed on or sprayed on, though both methods have their own benefits and particular drawbacks.
Even if you understand the basics, there are a fair few terms that get thrown around when dealing with paints. Unfortunately, marketing departments have been let loose over the years to further muddy the waters and confuse and misuse a lot of the definitions involved. As a result, it’s understandable to have a couple of questions about automotive paints, and we hope to answer a few of these below:
- What’s the difference between Enamel and Acrylic paints? - Here is a perfect example of terms becoming mixed up. It’s a common misconception that enamel and acrylic are opposite types of paints, due to the thought that acrylic paints are water-soluble and enamel are oil-based. This isn’t really the case however since you can have acrylic enamel paints, or synthetic enamels. The reason for the mix-up is that traditionally, all enamel paints were non-water based and so acrylic paints were seen as their alternative. Now however, you can have water-based enamels, given that the term enamel merely refers to a high-gloss “shell” like coating.
- What is 2K or two pack paint? - Two Pack, Twin Pack or 2K paint is paint that requires a hardener to be added in order for it to cure. Usually Acrylic enamel will be a 2K paint, as will almost all Urethane paints. 2K paint is super toxic, so the use of proper respirators and protective gear is absolutely necessary. It’s common to confuse one and two pack paints with single and two stage paints, but remember - “Pack” or “K” refers to the need for a hardener or activator, whereas “stage” refers to the need for a topcoat of clear paint.
- Which Primer should I use? - This is a common question, and with so many different paint manufacturers producing so many different types of primer, it’s a completely understandable one. The simple answer is that your choice of primer should depend on what you are applying it to, as well as what’s being applied over it. For bare metal, it’s best to use an etching primer as this will allow the paint to really adhere to the metal surface. Sandable primers should ideally be used over the top of existing paint or etching primers, and epoxy primers can be used pretty much anywhere since they are great at everything but are often appropriately expensive. Some paints don’t actually require the use of primers, though it’s never a bad idea to add a little more protection and increase your paint’s adherence.
- How long should I wait for the paint to dry? Drying times for paint are affected by the products used in the paint and the drying method. In commercial paint and body shops, the paint can be baked on - meaning that the car will be ready to go in a short time, however most of us don’t have the luxury of a giant oven, so will usually have to settle for a warm and dry garage instead. When you paint a car you need to apply a number of coats and the time between each coat is referred to as the “flash time.” This time will vary, but is usually around 15 to 30 minutes. Simply put - always refer to the instructions on your paint tin, as each type of paint will vary, and each manufacturer will recommend different drying times be allowed.
There you have it. Hopefully this article will have given you a better idea as to what a lot of the jargon means, and you will be able to differentiate between the types of paint available. If you aren’t sure, remember that you can ask one of the friendly experts in your local Supercheap Auto store and they’ll be happy to recommend the most suitable paint for your project. Obviously painting a whole car is a pretty big job, so it’s best to leave it to the experts if you aren’t confident, however with a little knowledge and a whole lot of prep work, you can easily tackle smaller jobs until you do build up that confidence and experience yourself.
Remember: always be sure to follow the instructions on your paint, and ALWAYS use appropriate safety gear.