(6) Primer Application. Brush the primer on the blade in the area shown in figure 3-17 where the
coating will be applied. Allow the primer to dry at least one hour at 70 degrees F or above. Do not
handle the primed surface. If the primer surface becomes contaminated, lightly wipe it with denatured
(7) Mix Coating. Stir Part A of coating before using. After the primer dries, mix 3/4 beaker of
AGC 1201-1R polyurethane coating Part A with 1/4 beaker AGC 1201-3R Part B in a can and mix well.
Do no stir again after it is mixed well. If a skin forms on top of the coating, remove it.
(8) Coating Application.
(a) Brush on 5 coats to the entire area shown in figure 3-17, allowing five minutes minimum
drying time between recoating a specific area. Brush on heavy coats with light pressure to avoid
damaging previous coats. If lumps form in the coating, discard and mix a new batch.
(b) Remove masking tape after the first 5 coats are applied and apply the remaining coats by
eye. Total number of coats are show in figure 3-18. Allow the coating to cure 24 hours at 70 degrees F
Wet primer can be cleaned up with denatured alcohol or MEK. Wet
coating can be cleaned up with MEK.
e. Polyurethane Curing. After polyurethane application, allow 24 hours curing time.
f. Tape Repair. Replace the entire damaged piece of tape. Remove with a plastic scraper. Replace
per the installation instructions.
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 roughness
must be sanded off the surface using 400 grit sandpaper. Simply, the sur-
face should be at least as smooth as you can get it by sanding with 400 grit
(1) Clean the surface by rinsing with isopropyl alcohol and wiping dry with clean untreated paper
towels or rags.
(2) 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.
(3) 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.
(4) Prepare a "wetting" solution as follows: To a pint sized spray bottle, add 2 drops of liquid
dishwashing detergent and 1/2 cup of isopropyl alcohol and fill the bottle with clean water. (The actual
mixture is: 75% water, 25% isopropyl alcohol and 2 drops of liquid dishwashing detergent per one liter
Change 3 3-37