Polishing & Paint Correction2 min read

Heavy Cut on Concave Panels: Check the Pad Contact Footprint

On a concave panel, a pad can bridge the recess while its edges carry much of the contact.

Updated · NANOLAB Knowledge

On a concave panel, a pad can bridge the recess while its edges carry much of the contact. A compound that performed well on a flat test area may then cut unevenly. The first question is whether the pad face is reaching the intended surface in a controlled way.

Examine the geometry with the tool stopped

Follow the machine’s handling instructions and inspect the available space without running the pad. Consider the backing plate, pad diameter, pad profile and surrounding raised edges. Do not force a large pad into a recess or assume that extra pressure will make an unsuitable combination conform safely.

The pad’s flexibility is only one part of the decision. A very flexible face may fit the contour while the backing plate or machine body still creates a contact risk. The assembly needs clearance throughout the planned movement.

Test the actual recess

Where access is suitable, use a small representative area within the concavity. Work with the manufacturer’s supported combination and watch for unstable movement, intermittent rotation on a free-spinning DA, or a narrow band of concentrated residue. Stop if control becomes unreliable.

After cleaning, inspect both the centre of the recess and its shoulders. Better correction at the shoulders with unchanged marks in the centre suggests an uneven working footprint. More compound or a longer cycle will not necessarily solve the contact problem.

Choose a controlled alternative

Options may include a compatible smaller machine and pad, a different supported pad profile, careful hand work within the product’s intended use, or retaining defects in an inaccessible area. Changing tools requires a new test because correction rate and finishing behaviour can change.

Keep vulnerable edges outside the aggressive working area. Masking identifies and protects boundaries from incidental contact and residue, but it is not permission to load a rotating pad against an edge.

Document the method used in the recess separately from the flat-panel recipe. The successful result is even, accepted correction with stable access, rather than forcing the same pad to cover every shape on the car.

For current NANOLAB product instructions and compatibility, visit product documentation or contact the technical team.