For best results: To allow the edge of the sealant bead to blend with
the 3M 8663 polyurethane protective tape and paint. Higher tempera-
tures will require less time for the sealant to gel. Lower temperatures
will require more time for the sealant to gel, so some adjustment in
the 10 minutes may be necessary. The objective is to get the masking
tape off while the bead of sealant is still flow able, to let it blend with-
out a sharp edge.
(19) Inspect the edge seal application for any small air bubbles and if any are found, they can be
relieved by pricking with a hypodermic needle.
(20) The rotor blade is ready to return to service after the sealant is well cured, and the 3M 8663
polyurethane protective tape has had time to reach an acceptable level of adhesion. This is achieved
after 24 hours at 72 degrees.
d. Tail Rotor Agcoat Application.
TASK L-100 polyurethane paint may be used in place of agcoat. TASK
L-100 may also be utilized to repair agcoat.
(1) Cleaning. Clean area shown in figure 3-17 with cheesecloth or machinery towel dampened
with MEK, isopropyl alcohol or denatured alcohol.
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) Masking. Mask off area for polyurethane coating with Duck tape as shown in figure 3-17.
Surface preparation and cleaning are the most important steps to
insure proper adhesion.
(3) Surface Preparation. Scuff the masked off area with 120 grit sandpaper. Only sand in a
(4) Cleaning. Wipe the masked area several times with cheesecloth or machinery towel
dampened with MEK.
(5) Mix Primer. Stir Part A of primer before using. Mix equal amounts (4 oz. of each) of AGC
1201-7 primer parts A and B in a beaker and stir well. Close can and bottle after pouring out required
Consult U.S. Army Environmental Hygiene Agency (U.S. AEHA) Technical
Guide 144 Guidelines for Controlling Health Hazards in Paint Operations
and the Material Safety Data Sheet (MSDS) for guidance. Use safe glasses,
gloves, and disposable (Tyvek) coveralls. Avoid skin contact. Always apply
coatings so that any spray or vapors are directed away from breathing zone
of individuals. Use respirator protection components, table 3-10.