Curing; Deep Scuff Through Neoprene Surface - Piper Cheyenne IIIA Airplane Maintenance Manual

PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCE MANUAL
A. Airfoil - Description and Operation (continued)
(f) Curing
The vulcanizer listed in Chart 5 is adjusted at the factory to heat to 285
°
+ 5°F, using line
voltage specified on the name plate. All curing times in this manual are for 285°F. If line
voltage is low, the vulcanizer will not heat to 285°F and curing times are longer than specified.
Since curing time varies with type and position of repair, times are given for each specified type
of repair.
Cure repair as follows:
NOTE: Over-curing destroys the flexibility of deicer. Under-curing prevents proper bonding.
Always watch cure time and temperature carefully.
(1.) Preheat vulcanizer.
(2.) Place sponge pad over bottom of unheated plate.
(3.) Place piece of clean, unwrinkled (or silicone treated) paper over sponge pad and deicer
over holland with area to be cured centrally located over bottom platen. (Repair side up.)
(4.) Place another piece of smooth, clean holland over area.
NOTE: If holland or silicone treated paper is not available, spread thin coat of soapy
water over surfaces of metal curing sheet and sponge pad. Allow to dry
thoroughly.
(5.) Place metal curing sheet over holland and clamp heating element in place. Ensure metal
curing plate is at least 1 inch larger overall than heating plate. Hand tighten heater firmly.
(6.) Cure full allotted time for each repair.
(7.) Test each repair thoroughly after it has cured. Flex and stretch area by hand several
times and in a tube; inflate to 25 psig.
(g) Surface Scuffs
(1.) Wash surface, apply one coat of conductive cement, and allow to dry thoroughly. Add
another coat and allow to dry. Dip finger in conductive cement solvent (Isopropyl Acetate)
and rub down with light circular movement.
(2.) Wipe surface lightly with Isopropyl Acetate moistened cloth.
(3.) Allow to dry thoroughly. Dust lightly with soapstone.
(h) Deep Scuff Through Neoprene Surface
(1.) Mark area and carefully cut 0.010 inch Neoprene surface ply with knife. Prevent surface
ply from peeling beyond marked area when using buffer. Ensure area includes full width
of tube and approximately 1/2-inch beyond scuff.
(2.) Using buffer, route down until all pits are removed. Buff 1/8-inch around outer edge of
routed area. Mask off outside of buffed area and cement.
(3.) Using mill or putty knife, apply Neoprene putty. Fill cavity flush with surface and ensure
cavity is completely filled. Remove masking tape and cure for 20 minutes.
(4.) Restore conductive surface.
EFFECTIVITY:
040-999
30-10-00 PAGE 15
Jan 10/90