Delamination

Separation of layers.

Cause

• Poor glass saturation.
• Dirty surface.
• Glass content too high.
• Failure to remove air-inhibition coat before adding layer.

Fisheye

Small globular mass that has not blended into surrounding material.   Particularly evident in transparent or translucent materials.

Cause

• Dirty surface.
• Foreign matter falling on resin.

Dry Spots

Area of reinforcement that was not wetted with resin.  Usually at edge of laminate.  Dry spots usually associated with molding operations.

Cause

• Not enough resin used.

Pimple

Small sharp or conical pimple-like elevation on surface.  Pimples are usually resin-rich.

Cause

• Dipped resin or small bubble.
• Working on area after resin has cured.

Pit or Pinhole

Small regular or irregular crater on surface, usually with nearly equal width and depth.

Cause

• Air bubbles that rise to surface, which cures before smoothing out.

Resin Pocket

Accumulation of excess resin in a small localized area..

Cause

• Improper layup.  Glass separates and void fills with resin.

Scratch

Shallow mark, groove, furrow or channel.

Cause

• Improper handling or storage.

Worm Holes

Elongated void in surface or covered by thin film of cured resin

Cause

• Usually found in small-diameter pipe where cure is from the outside and progresses towards the mandrel.

Wrinkle

Crease or wrinkle-like surface imperfection in one or more plies of molded-in reinforcement.

Cause

• Improper layup.
• Too rapid cure.
• Use of old resin
• Fold in release film on the mold.