Perform Steps (6) to (10) for one blade at a time.
(6) Application of Adhesive Promoter. Apply a thin coat of No. 86 adhesive promoter to the area.
Allow to dry at least five minutes, but not more than one hour before applying tape. Any bubbles
encountered dung the application process may be removed by continuous squeegee stroking towards
the edge of tape or by puncturing the bubbles with a needle and applying pressure to the wet adhesive.
Do not puncture bubbles after the adhesive has dried.
(7) Masking Tape Removal. Remove masking tape.
(8) Polyurethane Tape Preparation. Peel back one of the center (1 inch wide) backing strips from
the 4" wide tape approximately 3 inches as shown in figure 3-1, sheet 3 for 8" tape.
(9) Tape Alignment. Align the tape in the position shown in figure 3-37.
(10) Tape Application. When the tape is in proper position, press the exposed portion on the blade
as close to the leading edge as possible. Press down on the tape, working toward the trailing edge to
prevent trapping air bubbles. See figure 3-1, sheet 4. Peel backing strip back while keeping tap
aligned and pressing down toward the trailing edge. Remove the backing strips one at a time, working
toward the trailing edge. See figure 3-1, sheet 5. Thoroughly press down tape.
The structure to which the polyurethane protective tape, 3M 8663,
is to be applied should be in recent overhaul or new condition. This
means that repairs have been made and the part has been primed
and painted in accordance with the appropriate technical directive
for that part.
The rotor blade must be smooth. Any dirt inclusions or paint rough-
ness must be sanded off the surface using 400 grit sandpaper. Simply,
the surface should be at least as smooth as you can get it by sanding
with 400 grit sandpaper.
(11) Clean the surface by rinsing with isopropyl alcohol and wiping dry with clean untreated paper
towels or rags.
(12) Using a small clean rag, apply a thin coat of #86A adhesion promoter to the entire area of the
rotor blade that is to be covered with 3M 8663 PPT film. Let the 86A dry 15 minutes, prior to application
of 3M 8663 PPT film.
(13) Cut a sheet of 8663 polyurethane protective tape (PPT) to the size of the area to be covered
leaving a margin of 1/8 inch around the perimeter. This margin will later be used for application of the
edge sealant around the perimeter of the PPT sheet.