If you’ve decided that your ride may need a slight visual update, applying some new paint can certainly fulfill that expectation. However, a flawless paint job requires more than just a skilled hand and correctly chosen paint gun. Moreover, it’s the preparation applied to the bare skin before the final coat of paint is laid, which creates the highest luster.
If you think about it, you would never apply paint directly to your cars metal or fiberglass surface, right? It’s all in the preparation, tools, primer, and the paint you’ve chosen. To be honest, the paint process can be quite extensive. With mountains of material and information available, this task might seem a bit daunting. In an effort to clear the fog, we’ve spoken to a few industry pro’s to find out which tools and methods you’ll need to get the job done, correctly.
To avoid some of the pitfalls and blind corners, follow along as we discuss which types of primer to apply, color basics, and which paint gun is right for your particular application. We’ve also included several basic steps on how to apply a quality paint job correctly.
What to Shoot?
There are two basic types of primers used today for automotive refinishing; one-part Acrylic Lacquer primer and two-part Urethane Primer. Acrylic Lacquer is the easiest to use – mix it up, strain it into the cup and apply a layer of primer using a 1.4 spray gun tip. Allow the primer to dry thoroughly before sanding with 600-grit paper and applying second and potentially a third coat.
Primer or paint, a clean and properly heated spray booth is important to keeping debris out of your primer coat. The temperature of the booth will make a dramatic difference in the primer used. Check with your paint professional to determine which primer is right for the conditions.
Much like paint, primer should also be strained prior to use. The right spray gun tip size is required to ensure that the proper amount of primer is applied. Test the gun before spraying, varying the air pressure until you achieve the proper pattern and amount of material. Wipe down the body thoroughly with grease and wax remover using clean microfiber toweling.
The two-part urethane primer is a popular choice by many industry professionals. It provides better adhesion and includes a catalyst hardener for durability; creating a hard, final shell that won’t shrink or swell. Most of the time a 2.0 spray gun tip is used to increase the amount of material applied. Three coats are generally applied waiting 10 minutes between coats. Overnight drying is advised prior to blocking with 600-grit sandpaper.
What Color Primer Should I Use?
Primers come in a variety of colors. While light grey is the most common, darker colors can be helpful when blocking as darker hues will demonstrate the straightness of the vehicle lines more clearly (i.e. black paint shows imperfections more easily than lighter colors). In addition, the primer color can effect the final color of the paint applied. Just like the problems encountered when painting a room where a lighter color is applied over a dark base coat and vice versa, more coats may be required to get the hue you want.
A tack rag will pick up any remaining debris left on the surface. Tire covers are great for keeping overspray off your high prices wheels. When possible, use a spare set of wheels and tires to keep the shiny ones out of harms way. Prime smaller areas to maintain control – four feet at a time. Make sure that every section is covered, too. When painting wheelwell openings, this means turning the gun and spraying up into the well edges and lips. Make sure that every section is covered which with wheelwell openings means turning your gun and spraying up into the well edges and lip. This panel sports fresh urethane primer. Three coats were applied before allowing the area to dry overnight and block in prep for paint.
The primer stage is a critical element in the painting process. Remember to keep your equipment clean, especially your spray gun, and filter all of your fluids to ensure that the spray gun nozzle stays clear. If it clogs, clean it with acetone and start over. During the primer process, it’s important to remain patient. Prevent runs or sags on the body by taking your time. Weather and temperature also play a key role in the amount of time the applied product will need to dry. If spraying in a booth, monitor the temperature carefully and apply the primer to the entire car in one setting. In most cases, three quarts to a gallon of primer will be needed to complete this process.
Note the clean and well-lit spray booth. It's critical to monitor the temperature in the booth as well as it will affect the amount of thinner and material used, drying times between coats and the final results. Here, master painter Mark Oja of Paul Gonzalez Custom Cars illustrates the proper painting technique on a panel. Note the proper use of safety suit and respirator. We'd also recommend gloves and goggles as well.
Each panel was primered and block sanded with 600-grit paper prior to painting. A table such as this is great to keep the parts from moving when painting. Covering the top of the table with masking paper will keep it from receiving extra layers of paint and primer in future paint efforts.
If you have any questions about paint or primer, a good source for answers is the Sherwin-Williams website and heading to the Troubleshooting link could solve everything.
This site provides a great source of info and even provides a glossary of terms should you get stuck understanding the information on the paint can. It’s even bi-lingual.
OK, you’ve sweat out the details and now it’s time to receive your reward. While it may seem like it’s taken forever, applying a fresh coat of paint is where the magic begins. But there’s nothing more frustrating than getting to the final step of the painting process, only to have something go awry.
The best insurance here, check with a professional should you have any questions. Additionally, shooting test panels and keeping your spray gun clean will also help ensure that the final result matches your vision.
The Color Basics
There have been countless kinds of paints applied to cars over the years. Today, the two-step acrylic enamel or urethane paints are preferred. Lacquer has been all but outlawed in most states so original Corvettes in OE lacquer are a thing of the past. But have no fear, the modern paint products are excellent and will give you better than OEM results. Finishing the paint process with a clear coat top coat will add durability to the paint surface and add to its depth.
You just can’t be too clean when you are about to paint. This panel was cleaned with soap and water and then grease and wax remover to eliminate blocking debris. A tack rag gently wiped over the surface is great, too. Complex pieces like this deck lid require compressed air to get out the last bits of water and dust. We used Sherwin-Williams Ultra 700 Red Metallic Urethane for this project. Chemicals and colors in the paints can become separated with time. There is a lot of material that floats to the bottom of the can, so make sure you stir it thoroughly and often. Filter the paint as it enters the paint gun reservoir. Note that this is a High Volume Low Pressure (HVLP) gun. These guns are especially efficient and only require about 10 psi to operate. Paint filters are fairly standard but don’t forget to grab them when you pick up you paint.
Both acrylic enamels and urethane are applied similar to lacquer finishes but fewer coats are needed over those legendary 20 coat lacquer jobs you’ve probably heard of from old guys still crusty with overspray. This is because more paint is applied with each new-style paint coat because of the higher viscosity of the paint (usually a half to one part thinner to 1 part primer). In most cases it takes three coats of base color and three top coats of clear. The best bet is always to enlist to help of a local pro to supply some guidance here.
Gunning For You
If you’ve been napping for a few years, you probably missed out on the big change in spray guns. For the most part use of the old syphon spray guns, which required a high pressure lines, are not used. Actually they are not the preferred style of gun today for a variety of reasons, the least of which is the wrath of local pollution control officials who have outlawed their use.
The bottom side of the panel is painted with the base coat making sure to cover the edges. The entire panel will be painted with the base coats, top and bottom and then the top clear coats will be applied. Spray gun nozzles are adjustable (the inner fittings are changed) dependent on the paint being used. Ask your paint professional which one is right for your project. This is a 1.6 nozzle – for those who were wondering. Three coats of base color paint were applied and then three coats of clear. Note that we worked the panel from each side into the middle making sure to cover the edges. The gun should never be closer to the panel than 18-inches and can be tested before hand to make sure the pattern is appropriate. If the gun spits at any time, stop, clean out the nozzle with acetone, and start again. Avoid having the air hose or spray gun contact the wet painted panel or vehicle – or you will have to repair it by letting it dry and sanding out the flaw.
So what’s the alternative? HVLP guns are the most common spraers used today. In essence, instead of drawing paint from the bottle fitted below the spray gun system, the paint is gravity fed into the gun through a tank, which sits above the mechanism.
Before you start complaining about this new system, realize that these guns are far more efficient than the syphon spray guns. The new HVLP’s deliver as much as 80 percent of the product to the surface, yet require as little as 10 psi of line pressure to operate. Syphon guns often need 45-70 psi of line pressure but only apply about 40 percent of material. Regardless, a small compressor (minimum 5hp) is still considered minimum support for an HVLP spray gun.
Ready to Shoot?
As we’ve mentioned before, prep and safety are keys to achieving a great final product. Purchasing a cheap, albeit complete paint suit is a great way to keep paint and other toxic products off your skin and clothing. Wear a respirator with two air filters and some form of head covering with goggles. Keep your area clean and you’ll be rewarded with a great paint job. More importantly, you’ll create less work by keeping dust and dirt off of the painted surfaces. There are few things more frustrating than inspecting your work and finding one small flaw in an otherwise perfect panel. Keep it simple, be safe, and practice your technique. You’ll be glad you did!