In the repair of reinforced plastic parts, the final step is to refinish the part with a finish identical to the original, or an acceptable substitute. In refinishing radomes and other surfaces that enclose electronic equipment, consult NAVAIR 01-1A-22. Do not use metallic pigmented paints or other electronic reflective-type materials because of undesirable shielding and interference effects. Always use the materials recommended in the applicable structural repair manual for refinishing both the interior and exterior surfaces of reinforced plastic components. Reinforced plastic components whose frontal areas are exposed to high speeds are frequently coated with a rain erosion coating. Rain erosion coatings protect the component against pits that are caused by raindrops hitting the component at high aircraft speeds. These pits or eroded areas can cause delamination of the component glass cloths if allowed to progress unchecked.

Rain erosion-resistant coatings for reinforced plastic components conform to Specification MIL-C-7439. Coatings that conform to this specifi-cation are classified as Class I and Class II.

Class I is a rain erosion-resistant coating that is furnished in kit form. This kit consists of a primer, accelerator, diluting solvent, and neoprene. Class II is a rain erosion-resistant coating with an additional surface treatment to minimize radio noise resulting from precipitation static on the coated surface. This coating is also supplied in kit form and consists of a primer, accelerator, diluting solvent, neoprene, and antistatic coating.

These kits (MIL-C-7439, Classes I and II) are packaged unaccelerated to provide longer shelf life. The neoprene is ready to use only after the catalyst (accelerator) has been added. The material in these kits should be mixed and applied in accordance with the instruction sheet supplied by the kit manufacturer.

Figure 14-15.Foam-type puncture repair.