Grit-Blasting or Sandblasting

This method may also be used if available. A specially-trained operator is needed to produee uniformity within pieces by sandblasting. A elean, uniform-size grit is essential for proper surfaee preparation with sandblasting. This may be a problem when treating GRP surfaces, that is why this technique is rarely used. 

After sanding or sandblasting, the surface is sometimes wiped with solvent, such as MEK, acetone, toluene, TCE, Freon TF or Freon TMC, depending on the known mold lubricants. In some cases, a solvent is used before and after abrading the surface. If water-break-free surfaces are not obtained, the procedure should be repeated. 

In general, bond quality diminished with increased surface exposure time (SET). The best overall adhesive evaluated was epoxy film adhesive, which was found to be the least sensitive to the method of surface preparation used. In general, the best result was obtained when GRP laminates were bonded within 4 h after sanding. If absolutely necessary, bonding can be carried out after periods of time of up to 14 days SET, wifli only moderate strength loss. 

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