TB 1-1615-351-23
(12) 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.
(13) 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.
(14) 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
of solution.)
(15) Remove the liner from the sheet of PPT. Liberally spray the adhesive side with "wetting
solution" that was prepared in step #4 above. Also spray the surface of the part to which the PPT is to
be applied.
(16) Carefully position the PPT on the part. Use a plastic squeegee, starting at the middle of the
sheet, and remove the wetting solution from beneath the PPT sheet, by using long overlapping strokes.
If you should trap an air bubble, lift an edge to allow the bubble to be removed. When the edge is lifted,
respray with more "wetting solution" to insure that no air is trapped under the PPT. Use a clean rag to
mop up the excess water solution at the edges to prevent the water solution from "wicking" back under
the tape.
(17) Inspect the installation for lack or air or water bubbles. It is permissible to remove a few small
"blisters" by piercing them with a hypodermic needle, and pressing on the bubble to exclude the
air/water.
NOTE
Repeat Steps (6) to (10) for each blade.
NOTE
For a neat job, use masking tape to mask the topside of the PPT
sheet 1/32 inch inside the perimeter of the edge.
NOTE
The application of edge sealant is particularly important in main-
taining 3M 8663 polyurethane protective tape integrity when applied
at butt joints of adjacent PPT.
(18) Assemble a nozzle and a cartridge on the 3M EPX applicator. Squirt out a small quantity to
insure that a uniform mix is attained. Using the nozzle, apply a 1/8 inch bead around the perimeter of
the 3M 8663 polyurethane protective tape panel. Allow this to set up for about 10 minutes, before
removing the tape. The sealant should still be liquid.
NOTE
For best results: To allow the edge of the sealant bead to blend with the 3M
8663 polyurethane protective tape and paint. Higher temperatures 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
flowable, to let it blend without a sharp edge.
Change 3 3-131
