Streamline Your Work
Not all projects require sanding, but for those that do, the best finished product often depends on thorough sanding at the outset. Beginning with lower-grade sanding paper such as 250- or 300-grit is a fine way to start. Many painters shift the direction of sanding with each subsequent pass, avoiding straight horizontal or vertical strokes. A striated approach will enable you to more fully and evenly cover the entire area to be painted, and as you work upwards to finer grits, you’ll need to know the base is level and has been sanded accordingly.
Hand-sanding with a flexible foam or rubber block may ease projects with heavy contours. After sanding is complete, a few quick blasts with compressed air in one direction will shake loose any remaining dirt or grit from the project. Last, use a grease remover or waterborne cleaner to pick up all remaining material. Anti-static wipes will also help reduce dust as much as possible.
Booth Prep & Maintenance
Most paint booths are well ventilated, highly advanced spaces in which professional painters can focus on the task at hand and get to work quickly and efficiently. Nonetheless, painters should regularly check exhaust system filters and replace anything in poor condition. The same is true for lighting; since you can’t paint what you can’t see, ensure maximum visibility by replacing dim or burnt-out lights immediately. Shadows in the booth can wreak havoc on the paint job, especially with darker colors and tones.
Establishing regular booth cleaning and maintenance habits will go a long way toward easing future paint jobs. A clean booth will protect the cost of its investment, prolong its life and make paint prep and cleanup a pleasure and not a pain. Regular sweeping, washing the booth and keeping it free of floating particles and will help protect the paintable surfaces of your projects as well.
Now, the fun part! Here are some strategies to raise your game:
Be safe. Always wear proper eye protection, an anti-static paint suit and quality gloves when handling paint materials. An air-supplied mask or hood respirator is paramount when in the booth.
Mix and prep enough paint. Don’t let a good project go to waste because you were short on paint. The best paint management software systems for the mixing room have minimum-mix quantities built right in for every vehicle and repair that comes your way.
Speed things up. Establish an air-dry spot repair process in your shop for minor dings and scratches. Your customers will appreciate it, and this is a great alternative to paintless dent repair.
Use technology. The new UV-cure primers are great for spot repairs—check out the OneChoice® UV primer system with easy aerosol application, ready to sand in two minutes. And on the color-matching front, the latest spectrophotometers bring color formulas right to your fingertips in an instant, communicating directly with your paint room software.
Build it up right. Proper film build is the key to clearcoat durability. Too low, and you can get premature film failure, dieback and poor appearance. Too high can lead to solvent pop and potential adhesion failure. Aim for a final clearcoat film build of 2–2.5 mils. Knowing the film build is especially critical if you plan to buff afterwards—plan ahead!
Spray Gun Strategy
There are more options than ever for your primary paint tool, so ensure you have the one that works for you. The best gun will fit your hand, be simple to prep, spray, and clean, and provide similar results with regular technique.
Some guns are specifically designed for primers and basecoats, others for clearcoats and flake. Budget permitting, a combination of all three is ideal. A dedicated clearcoat gun is always a good idea as it sprays the final (and prettiest) coat.
Hold the spray gun perpendicular to the project surface and try to maintain that distance for the whole project. Spray in deliberate, controlled strokes, keeping your wrist and elbow straight, moving your arm from the shoulder over the panel or project. Spray over the end of the entire panel to ensure a regular coat—don’t tilt your wrist outward to get the last little bit. You’ll get uneven results at the edges.
Clean your spray gun thoroughly. Many manufacturers provide a simple brush to clean the gun and cup inside and out. Flush the gun with the recommended material afterward—water-based guns should be flushed first with tap water and then the recommended cleaner. Never clean the spray gun air cap or nozzle with a hard pen point, knife or any other metal object that may damage it. Soft-surface nozzle cleaners are available.
Win with Waterborne
The increasing use of waterborne paints bears mentioning. Here are some tips to keep in mind.
Ensure that your compressor and drier are providing clean, dry air—use a temperature and humidity gauge to check for less than 10 percent humidity in the line.
Ensure good air flow in the booth, and make sure your booth is clean. Waterborne basecoats require sufficient air flow to dry properly. Check air flow by holding an anemometer 1 inch above the vehicle surface—75 CFM is a good target. Check air flow in the booth in all four corners, as well as above the vehicle roof line and along the sides of the rocker panels.
Basecoat viscosity greatly influences application and final appearance. Check periodically to ensure consistent performance—PPG recommends 23–28 seconds using a No. 4 DIN viscosity cup. Too thick? Add thinner. In high temp and high humidity, adjust viscosity to the lower range (23-24 seconds). This provides thinner coats and will dehydrate faster.
The Painter's Playbook is presented by PPG and SATA/Dan-Am Co.