(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
(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
(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
(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
For a neat job, use masking tape to mask the topside of the PPT
sheet 1/32 inch inside the perimeter of the edge.
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.
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.
(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.