The cost of repairing clear-coat runs and sags depends on whether they can be levelled and polished or whether the affected panel must be sanded and resprayed. Malaysian body shops normally need to inspect the size, depth and location of the defect before providing a reliable quotation. A small run on a flat door may require less work than a heavy sag along a curved bumper, wheel arch or body line. Costs can also increase when the defect has entered the basecoat, the surrounding clear coat is thin, or several panels on your car are affected.
When sanding is sufficient and when respraying is needed
Runs and sags are symptoms of excess wet film or poor application control, not automatic confirmation that the thinner is faulty. Possible causes include applying coats too heavily, holding the spray gun too close, using an unsuitable gun setting, allowing inadequate flash time or adding excessive slow thinner. Products such as 2K Slow Thinner T28 should only be mixed with a compatible 2K Auto Clear at the ratio stated in its technical data sheet; it does not replace the required hardener. Once the coating has cured, a body shop may carefully reduce a raised run, wet-sand the area and machine-polish it. Cutting into the colour coat can create a visible patch and make refinishing necessary. Do not wipe, press or polish a fresh sag while it remains soft, as this can distort the coating and complicate the eventual repair.
