Paint Runs

Paint runs occur when too much paint is sprayed onto a panel during the painting process, and it collects in a feature (for example, a contoured recess for the door handle) and then dibbles down, causing the run.

It is rare, but not unheard of, for cars to have runs from the factory. However, we most commonly see runs on cars that have had resprays. A good bodyshop would flat-and-polish out any imperfections such as runs and sags, but typically the cars we see with runs were not repainted at good bodyshops.

What it means

Paint runs are a spraying defect that appear when too much paint or clearcoat is applied in one area. Instead of flashing off and sitting level, the wet paint sags under gravity and flows down the panel, forming raised drips, curtains or wavy lines. You can usually feel a paint run with your fingertips as a ridge standing proud of the surrounding surface, often most obvious on vertical panels and sharp curves.

Why it matters

• Very visible in reflections: Because runs disrupt the smooth surface, they stand out badly in reflections and under raking light, making even fresh paint look amateur or badly repaired.
• Requires reworking: Properly fixing paint runs almost always involves sanding them flat and then polishing, or in severe cases repainting, which adds time and cost.
• Indicator of application problems: Runs often point to poor gun setup, incorrect technique, paint too wet or reduced, or not enough flash time between coats.

Where you’ll see it

You will see paint runs mentioned on bodyshop estimates, smart repair reports and quality control sheets, often as “runs and sags” or “runs in clearcoat”. Customers might simply describe them as drips in the paint. They are most common on vertical panels such as doors, wings and bumpers, and on edges where paint naturally gathers.

Context

In refinishing, paint runs sit alongside other spray defects such as orange peel, dry spray and dust nibs. Minor runs can sometimes be corrected with a careful flat and polish, using localised wet sanding followed by machine polishing. Heavier or poorly positioned runs, especially on edges and body lines, may need the area to be repainted. Good lighting, correct gun setup and allowing proper flash times all help prevent runs in the first place.

Common mistakes

• Trying to polish a run out without first sanding it flat, which leaves the raised defect visible no matter how shiny the area becomes.
• Over-sanding a run on edges or body lines and breaking through to primer or basecoat while chasing the last trace of the defect.
• Re-spraying over existing runs without flattening them first, which simply buries the defect under more material and can make it even more obvious.
• Ignoring gun setup, temperature and flash times, leading to repeat runs on the same panel after a repair.

Written by Danny Argent. Last updated 18/11/2025 19:09