What are sanding marks under car paint?
Also calledFlatting marks, Lining up, Sand Scratch Swelling, Sand Scratches, Sanding Scratches, Scratch swelling, Streaked Finish, Tramlining
Fine straight lines showing through the gloss are sanding scratches. The surface was sanded too coarse and not refined before painting. The new paint shrinks as it dries and follows the scratches underneath. They show most in direct sun.
What kind of repair does it need?
It depends how bad they are. Light marks can be flatted, compounded and polished. Worse marks mean sanding until they are gone, then painting again.
Depth decides it. If there is enough good clear coat above the fault, it is sanded flat and polished. If levelling it would go through the clear, or the fault is in the colour, the panel is painted again.
What to do next
Take it back to whoever sprayed it. This is a preparation fault and a sign the job was rushed. A detailer may be able to polish out light marks. Deeper ones need the panel painted again.
Sources
- PPG GBpaint maker
Surface scratches under the paint film.
- Sherwin-Williams Automotivepaint maker
a minimum film thickness of the clearcoat (2 mils) is required to maintain adequate ultraviolet protection
Not sure what your car damage is?
Point your phone at it, or describe it. The answer in seconds, $8 AUD.
Check it