Maddison is head of content at https://www.paperlust.co
She is a communications professional, postgrad student, part-time librarian, and occasional wedding photographer. She loves words and drinking cups of tea
Weekends have long been the perfect opportunity for a good DIY project, but most people think of house and garden, not automobile. If you've never done it yourself, spray painting your car can seem like a pretty overwhelming task. You need to know how to use a spray gun, what paints you need and how to deal with common problems, not to mention all the little things you don't think of until you run into problems! What you need is an easy-to-understand, big picture overview of what you need to know. Luckily, we've got you covered.
What you need:
Filler Sanding block and abrasives. Spray gun Primer Base colour Clear coat (and hardener if required) Protective gear (mask and goggles)
Choose your primer and spray paint
It's important that you choose the right spray paint for your car to ensure your project is successful. There's three things you need: a primer, the base colour and a clear coat. Note, however, that no clear coat is required if you are using solid colours.
A primer is the first layer applied after sanding. Different types of primer serve slightly different purposes. A self-etch primer uses acid to help paint bond to the steel and aluminium. Epoxy primer prevents corrosion of metal and fibreglass. High-build primer is sanded after application and smooths imperfections to create a perfect surface for your paint. Urethane primer is a multi-coat primer that creates an extremely strong bond between the surface and the paint.
The base colour is the actual colour you're painting the car. Automotive paints are made up of a carrier agent, colour pigment and resin (the binder element). There are three main kinds of paint distinguished by the ingredient in the resin: urethane, enamel or lacquer. You'll likely be choosing between urethane and enamel. While lacquer is still sometimes used for show cars, it is a notorious pollutant that continues to pump toxic chemicals into the air after it is dry. Ask your paint supplier whether your chosen paint requires an activator for the paint to dry or a thinner to help it move through the spray gun.
A clear coat contains no pigment, but is used to protect the base colour and keep the finish free from scratches and chips. You have two options here: urethane and acrylic. Urethane-based clear coat is quick-drying and long-lasting, but it requires an extra chemical activator to help it set. Acrylic paint does not require extra additives since it is water-based, but it will dry more slowly and will not be effective for as long as a urethane top coat. You should also consider the size of the vehicle you are painting. The larger the car, the more slow-drying your clear coat should be. If parts of the coat set before you have finished the rest the finish will look layered instead of smooth.
Whatever types of paint you choose, make sure you use the same brand for every stage and layer. Companies design their products to work together, and switching brands means you risk incompatible formulas that can ruin your entire project.
Prep the panel
To get the perfect paint job you need to have a smooth surface for application. Tape up any areas that you don't want touched with the sander (or the paint later on) to protect them, and then begin.
Sanding is your first step, buffing out imperfections and creating a surface that the paint layer will be able to bond with effectively. For best results, use light pressure from an orbital sander to strip back to bare metal.
Filler can be applied to any dents or scratches in the panel. Mix the filler on a board until it is smooth and there are no air bubbles, then use an applicator or other tool with a smooth edge to apply multiple smooth layers to the dent, allowing it to cure evenly. After it is dry (usually 26 minutes or so), use a sanding block to level the filler with the surrounding area.
Your orbital sander can be used to feather the edges. If you don't have an orbital sander, you can create the gradual edge by hand.
Set up and test your spray gun
Ideally you should be using a gravity feed spray gun, also known as a high transfer efficiency gun, as they provide low overspray. Always wear proper protective gear when using a spray gun, as automotive paint is highly toxic. A mask and safety goggles will protect you from breathing in the dangerous chemicals.
Find a test surface such as a piece of cardboard, timber or an old panel. Test your gun, and watch the consistency of the paint. A dry finish right after spraying means you need to increase your fluid. Dripping or a texture like orange peel means you have too much fluid and should decrease it. Adjust your flow until you see paint spraying in the shape of an AFL football. If you are unable to get that shape you should check for blockages or other flow issues.
Adjust your air to the recommended pressure for your gun.
Consider the area you will be painting, and make a plan for overlapping each pass to ensure you keep a wet edge so that everything dries evenly and it's easy to maintain a consistent distance and angle when using your spray gun.
Once you have a plan of attack, feel well-practiced and are getting consistent results, it's time to spray paint your car! Start with the primer, sanding the primer down once it has cured if recommended by the paint manufacturer. Then comes the base colour. Adjust your fluid as you go, depending on the surface you are working on, avoiding dryness or dripping. Make sure you are getting a wide fan pattern, but not so wide that you end up with dry overspray.
The trick to getting great results from your spray gun is technique. Keep steady and consistent, leaving an even distance between the nozzle and the panel. Keep your knees bent and use your whole body to move the gun smoothly over the contours of the car body. Each pass should overlap the previous one by 50%, keeping the angle consistent to avoid the stripe effect that can occur when one edge of each pass is thicker than the previous one. Be careful to ease off the trigger slowly at the edges, as sudden stopping and starting will cause buildup of the paint in these areas.
Everyone has their own tried and true techniques and tips for spray painting a car, but following these basics will help keep you from getting confused. Start here and in no time you'll be developing your own style and preferences.