Use equal amounts of primer and coating on all blades to minimize balance
adjustments to main rotor.
(4) To apply polyurethane coating to main rotor tip cap do this:
(a) Primer, may be brushed on or sprayed on. If brushed on using paint brush, no thinning is required. If
sprayed on, primer must be thinned to 2 parts primer, 1 part methyl ethyl ketone. Mix primer part A and part B in equal
parts. Apply to area to be coated. Allow 1-hour drying time at 70F (21C) or above. Do not handle primed surface. If
surface is contaminated, lightly wipe using cleaning cloth, moistened with alcohol.
Brushed coats tend to result in 0.002-0.003-inch thickness.
Sprayed coats tend to result in 0.0007-0.001-inch thickness.
(b) Mix polyurethane coating, with polyurethane curing agent in 1-quart container (3 parts A to 1 part B) and
using paint brush, apply first layer of tip cap. Allow 2 minutes drying time between coats when sprayed and 5minutes
when brushed until desired thickness is reached. (figure 3-29). Allow 24 hours curing time, accelerated curing time hours
a 140 -160F.
Damage to main rotor blade can occur while removing tape from masked area of
blade. Hold cutting knife parallel to blade surface when removing tape.
(c) Remove masking by slitting coating at ridge created by the double layer of tape. Do not scratch or gouge
d. Applying L-100 Coating to Main Rotor Blade Tip Caps.
(1) Layout and mask as follows: