allow the top surface of the coating to dry, trapping the  solvents underneath. If another heavy coat is applied before  the first one dries, wrinkles may result. It may also have the  effect of lifting the coating underneath, almost with the same  result as a paint stripper.  Rapid changes in ambient temperatures while spraying may  cause an uneven release of the solvents, causing the surface  to dry, shrink, and wrinkle. Making the mistake of using an  incompatible thinner, or reducer, when mixing the coating  materials may cause not only wrinkles but other problems  as well. Wrinkled paint must be completely removed and  the surface refinished.  technical data sheet for “dry and recoat” times for the  appropriate temperatures and “dry to tape” time that must  elapse before safe application and removal of tape on new  paint without it lifting.  When masking for the trim lines, use 3M$^{®}$ Fine Line tape. It  is solvent proof, available in widths of  1 ⁄ 8 –1 inch and, when  applied properly, produces a sharp edge paint line. A good  quality masking tape should be used with masking paper to  cover all areas not being trimmed to ensure the paper does not  lift and allow overspray on the basecoat. Do not use newspaper  to mask the work as paint penetrates newspaper. Using actual  masking paper is more efficient, especially if with a masking  paper/tape dispenser as part of the finishing equipment.  After the base color has dried and cured for the recommended  time shown in the manufacturer’s technical data sheet, the  next step is to mask for the trim. The trim design can be  simple, with one or two color stripes running along the  fuselage, or it can be an elaborate scheme covering the entire  aircraft. Whichever is chosen, the basic masking steps are  the same.  The affected area needs to be sanded and recoated. At this point in the project, the entire aircraft has been painted  with the base color and all the masking paper and tape  carefully removed. Refer again to the coating manufacturer’s  If unsure of a design, there are numerous websites that  provide the information and software to do a professional  job. If electing to design a personalized paint scheme, the  proposed design should be portrayed on a silhouette drawing  of the aircraft as close to scale as possible. It is much easier  to change a drawing than to remask the aircraft. Start by identifying a point on the aircraft from which to  initiate the trim lines using the Fine Line tape. If the lines  are straight and/or have large radius curves, use ¾-inch or  one-inch tape and keep it pulled tight. The wider tape is much  easier to control when masking a straight line. Smaller radius  curves may require ½-inch or even ¼-inch tape. Try and use  the widest tape that lays flat and allows for a smooth curve.  Use a small roller (like those used for wallpaper seams) to  go back over and roll the tape edges firmly onto the surface  to ensure they are flat. Finish masking the trim lines on one side of the aircraft,  to include the fuselage, vertical fin and rudder, the engine  nacelles and wing(s). Once complete, examine the lines. If  adjustments are needed to the placement or design, now is  the time to correct it. With one side of the aircraft complete,  the entire design and placement can be transferred to the  opposite side. Different methods can be employed to transfer the placement  of the trim lines from one side of the aircraft to the other.  Masking Materials Masking for the Trim Spray Dust Spray dust is caused by the atomized spray particles from the  gun becoming dry before reaching the surface being painted,  thus failing to flow into a continuous film.  [Figure 8-21]  This  may be caused by: Painting Trim and Identification Marks Masking and Applying the Trim •  Incorrect spray gun setting of air pressure, paint flow,  or spray pattern. •  Spray gun being held too far from the surface.  •  Material being improperly thinned or the wrong  reducers being used with the finish coats. Figure 8-21.  Example of spray dust. 8-16