Cut 4 pieces of 4" wide polyurethane tape 36 inches long.
Cut 2 pieces of 4" wide polyurethane tape 16 inches long.
Cut 4 pieces of 2" wide polyurethane tape 30 inches long.
Surface preparation and cleaning are the most important steps to
ensure proper adhesion.
(4) Surface Preparation. Scuff the masked off area with 120 grit sandpaper. Only sand in a
spanwise direction, figure 3-41. Use of power polishing sander is permitted for this procedure.
Do not sand the bare metal skin of helicopter rotor blades. Sanding
bare metal skin reduces the structural integrity and fatigue life of
(5) Cleaning. Wipe the masked area several times with cheesecloth or machinery towel
dampened with isopropyl alcohol, or denatured alcohol, then wipe once again with a clean, dry cloth.
Perform Steps (6) through (10) for one blade at a time.
(6) Application of Adhesive Promoter. Apply a THIN coat of No. 86 adhesive promoter to the
masked area where the first 16-inch long piece will cover, as shown in figure 3-42. Allow to dry at least
five minutes, but not more than one hour before applying tape. Promoter can extend beyond end of
tape. Apply promoter in tape length segments to avoid contamination of coated surface.
(7) Polyurethane Tape Preparation. Apply alignment marks to outside surface of tape at the
center. Peel back one of the center (1-inch wide) backing strips from the 4" wide tape approximately 3
(8) Tape Alignment. Align the tape in the position shown in figure 3- 42 before pressing to blade.
(9) 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 3-44. Peel backing strip back while keeping tape aligned and
pressing down toward the trailing edge. Remove the backing strips one at a time, working toward the
trailing edge. See figure 3-45. Thoroughly press down tape. Apply 2 additional 36 inch long inboard
pieces of tape using No. 86 promoter as with the first piece. See figure 3-42. Any bubbles encountered
during 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.
(10) Remove masking tape.
(11) 2 Inch Tape Application. Scuff the 4" wide tape surface with 120 grit sandpaper in area to be
covered by 2 inch wide tape as shown in figure 3-46. Clean tape surface with MEK. Apply tape to blade
with No. 86 adhesive promoter as before.