5.9.2 Grit blasting of f‌ibre reinforced plastics (FRPs)


Grit blasting is a mechanical surface treatment method that is used to remove the uppermost layers of substrates and compact the surface.


Grit blasting is in principle suitable for fibre reinforced plastics.


  • Prior to grit blasting the surface must always be thoroughly cleaned and degreased, to prevent “incorporation” of the contaminants into the surface and making them thereafter very difficult or impossible to remove.
  • The grit must be chosen for the matrix (usually softer than the grit used for metals). Optimum blasting angle: 45°; The compressed air must be dry and oil-free
  • After grit blasting remove all dust, etc. from the surface (e. g. using a disposable, white cloth soaked with cleaning agent or using compressed air)

Points to heed:

  • Use suitable grit
  • Use clean grit (replace contaminated grit straight away)
  • Use dry, oil-free compressed air
  • Risk of some grit particles entering the plastic
  • Use of grit that is too hard or very high pressure can cause surface cracks and substrate deformation