What is rust under car paint?

Also calledCorrosion

Blistered or bubbled paint means the rust is underneath. The bubbling is rust pushing the paint up. What you see is smaller than what is there, because rust spreads under good-looking paint at the edges.

What kind of repair does it need?

The area is cut back well past the bubbling to clean steel, then treated, filled, primed and painted. If it has spread far, that section is cut out and new metal is welded in.

Class of work Cut back, treat and refinish, or new metal let in where it has spread.

The repair goes out to where the metal is still sound. That is usually wider than the bubbling you can see.

What to do next

Go to a panel shop and have it looked at in person. Nobody can price this from a photo. Ask them to show you how far it went once it is opened up. Insurance does not cover rust.

Sources

  1. PPG GBpaint makerLoose paint, bubbling and discolouration of the paint film, especially around body fittings, panel edges and seams.
  2. Standoxpaint makerMoisture penetration through broken areas in paint film
  3. Axaltapaint makerPaint has to be stripped/sanded back to the bare metal
  4. Naked InsuranceinsurerBecause this is something that you can expect from using your car, car insurance generally doesn’t cover it.
  5. Allianz AustraliainsurerIt doesn’t usually cover normal wear and tear or poor maintenance.
  6. GarageWeldingblogA rust hole is usually larger than it looks.

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Related

What is surface rust on a car? Light brown staining with the paint still smooth is rust at its earliest and cheapest stage. Learn why acting now saves money. What is rust through on a car? A hole or soft jagged metal means corrosion has eaten all the way through the panel. Learn how the repair cost compares with what the car is worth. What is hem rust on a car door? Rust along the bottom edge of a door comes from inside the folded seam. Learn why this starts inside and works outward. What is filiform corrosion on a car? Fine worm-like tracks creeping under the paint on aluminium panels are filiform corrosion. Learn why this is not rust.
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