Light orange peel can be wet sanded or buffed out with  polishing compound. In extreme cases, it has to be sanded  smooth and resprayed. Fisheyes appear as small holes in the coating as it is being  applied, which allows the underlying surface to be seen.  [Figure 8-18]  Usually, it is due to the surface not being  cleaned of all traces of silicone wax. If numerous fisheyes  appear when spraying a surface, stop spraying and clean  off all the wet paint. Then, thoroughly clean the surface to  remove all traces of silicone with a silicone wax remover.  Sanding scratches appear in the finish paint when the surface  has not been properly sanded and/or sealed prior to spraying  the finish coats.  [Figure 8-19]  This usually shows up in  nonmetal surfaces. Composite cowling, wood surfaces, and  plastic fairings must be properly sanded and sealed before  painting. The scratches may also appear if on overly rapid  quick-drying thinner is used. The only fix after the finish coat has set up is to sand down  the affected areas using a finer grade of sandpaper, follow  with a recommended sealer, and then repaint.  Wrinkling is usually caused by trapped solvents and unequal  drying of the paint finish due to excessively thick or solvent- heavy paint coats.  [Figure 8-20]  Fast reducers can also  contribute to wrinkling if the sprayed coat is not allowed to  dry thoroughly. Thick coatings and quick-drying reducers  The most effective way to eliminate fisheyes is to ensure  that the surface about to be painted is clean and free from  any type of contamination. A simple and effective way to  check this is referred to as a water break test. Using clean  water, spray, pour, or gently hose down the surface to be  painted. If the water beads up anywhere on the surface, it is  not clean. The water should flatten out and cover the area  with an unbroken film.  If the occasional fisheye appears when spraying, wait until  the first coat sets up and then add a recommended amount of  fisheye eliminator to the subsequent finish coats. Fisheyes may  appear during touchup of a repair. A coat of sealer may help,  but completed removal of the finish may be the only solution.  One last check before spraying is to ensure that the air  compressor has been drained of water, the regulator cleaned,  and the system filters are clean or have been replaced so that  this source of contamination is eliminated.  Figure 8-20.  Example of wrinkling. Figure 8-18.  Example of fisheyes.  Figure 8-19.  Example of sanding scratches. •  Forced drying method, either with fans or heat, is too  quick. •  Too little flash time between coats. •  Spray painting when the ambient or substrate  temperature is either too hot or too cold. Sanding Scratches Wrinkling Fisheyes 8-15