Some rotor blades may be painted with acrylic lacquer, and MEK can adversely
affect this paint and the subsequent quality of the erosion protection. In this case,
MEK should not be used as a cleaning agent.
(2) Layout and Mask. Layout and mask off main rotor blades for polyurethane tape application as shown in figure
(3) Cut Tape. Cut tape to dimensions stated in table 3-24.
Surface preparation and cleaning are the most important steps to ensure proper
(4) Surface Preparation. Scuff the masked off area with 120 grit sandpaper. Only sand in a spanwise direction a
shown in figure 3-1, sheet 1. Use a power polishing sander is permitted for this procedure.
Do not sand the bare meal skin of helicopter rotor blades. Sanding bare metal skin
on helicopter rotor blades reduces the structural integrity and fatigue life of the
(5) Cleaning. Clean area on blade to be covered with cheesecloth or machinery towel dampened with MEK,
isopropyl alcohol, or denatured alcohol, then wipe once again with a clean, dry cloth.
Perform Steps (6) through (8) for one blade at a time.
(6) Application of Adhesive Promoter. Apply a thin coat of No. 86 adhesive promoter to the area covered by the
first piece of tape, shown in figure 3-33. Allow to dry at least five minutes, but no more than one hour before applying
tape. Promoter can extend beyond end of tape. Apply promoter in tape length segments to avoid contamination of