Mottled paint, commonly known as “tiger stripes,” are common mistake many novices make when painting a car. The name comes from the streaks or stripes that appear in the finish, often lighter or darker than the surrounding paint. Several factors can create these imperfections that can ruin a paint job if ignored.
The good news is there are proven ways to avoid them, and they mostly come down to technique more than the paint you’re spraying. The best advice for first timers and other less experienced painters is to spray out a thorough test panel immediately before moving to your actual project. Reset your muscle memory and get focused on all the things that make a good paint job. Here is what you’ll want to pay attention to.
Well Mixed Paint
While most of the advice below focuses on technique, the paint itself is definitely a factor. It should go without saying that you need make sure the paint is well mixed to maintain a consistent color and finish. Metallics and micas are particularly prone to mottling if applied too heavily, allowing the additive particles to pool. Follow the manufacturer’s instructions for mixing ratios other components like activators, reducers, and other modifiers.
Temperature and Humidity
For best results, paint in a controlled environment with stable temperature and humidity levels. Variations in these conditions can affect the paint’s consistency and drying time, sometimes changing even as you’re spraying.
Proper Spraying Technique
Start by setting up your spray gun with the correct air pressure, fluid tip, and flow settings for the type of paint you’re using. Make sure you maintain a consistent spraying distance from the car’s surface (usually 6-8 inches) to ensure an even coat. You also want to make sure your spray gun is pointed perpendicular to the panel you’re painting, not diagonal. A diagonal application will lay the paint down thicker where the spray pattern is closer to the paint and thinner where it’s farther away. Tiger stripes are almost guaranteed if you’re not “squared up” when spraying.
Sufficient Overlap
You’ll apply the paint using even, overlapping strokes to ensure uniform coverage. It’s critical to make sure successive coats overlap the previous ones sufficiently. An old rule of thumb for solvent-based paints is a 50% overlap, and many experts recommend 75% overlap for waterborne paints. This means if the width of your sprayout on the panel is 8 inches, for instance, then you’ll start spraying each next row 4 inches away from the last (assuming 50% overlap).
Too much overlap leads to mottled stripes; too little leads to paint runs from heavy buildup. And remember, those figures above are just ballpark figures. You’ll want to test for your specific paint, spray gun, and conditions to dial in the right overlap before going to the car.
Thin Coats
Pros know to lay down multiple thin coats for an even finish, but a lot of novices try to lay it down heavy when they see thin spots. Applying several thin coats of paint rather than one thick coat helps prevent paint from pooling and causing tiger striping.
Drying Time
Allow each coat of paint to dry according to the manufacturer’s recommendations before applying additional coats. Typically 10-15 minutes between coats is adequate, but rushing the time between coats can lead to stripes.
I wrote the piece and have actually painted my own projects, but as a hobbyist not a professional. Thanks for adding that advice to the conversation.
you have to much overlap and too little backwards, too much creates the heavy and too light the striping. you also didnt add drop coats after your cover coats are applied. drop coats are 18″ away at 18 pounds of air pressure dropped with 75% overlap and this is also called the orientation coat too for pearls and metallics to make it evenly applied and no striping.
Spray fan pattern.
Flat washers in cup … not marbles
I notice Ya’ll dont say ANYTHING about Reduced Mist Coats ! Who ever wrote this article apparently has only Book Read, never sprayed a car. Proven Process that I can do to Eliminate Tiger Stripes & Mottling of Paint.