Pinholing in body filler

Small holes or bubbles located in or on top of putties or body fillers.

Cause:

Air or gas bubbles become trapped inside putty or filler during mixing or product application. These bubbles are exposed during the sanding process, creating small holes or craters in the surface.

Air or gas is trapped when:

1. Filler and hardener are mixed together using a 'whipping' motion (fast circular motion).
2. Adding too much hardener.
3. Applying heavy thick coats produces excessive heat, causing gas bubbles to form inside the product as it cures.

Repair:

1. Apply a thin layer of polyester glazing putty (properly catalysed and mixed), sand smooth and continue the repair process.

Prevention:

1. Mix putty/filler components by folding together and pressing down to eliminate air pockets.
2. Apply putty/filler in thin coats. Do not exceed manufacturer's recommended total film thickness.
3. Follow manufacturer's recommendation of correct ratio of putty/filler to hardener.