Loose Surface Ply In Dead Area (Non-Inflatable Area); Loose Surface Ply In Tube Area - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
TABLE XIV-VII. MATERIAL AND SUPPLIES FOR COLD REPAIR (cont.)
Part No.
Quantity
Description
The following materials may be obtained from local supply:
Toluol
As required
Clean, lint-free cloths
(preferably cheese
cloth)
Rolls
1 in. masking tape
I
Sharp knife
6 ft. long
Steel measuring tape
I
Fine sharpening stone
As required
320 grit emery cloth
As required
Hypodermic needles (22
gauge or smaller)
Methylethylketone (MEK) can be used instead of Toluol, however MEK
causes very rapid drying and provides only 10 seconds working time
compared with 40 seconds for Toluol.
2. Buff the area around the damage with buffing stick, Part No. 74
451-75, so that the surface
is thoroughly roughened.
3. Apply the patch to the deicer with the stretch in the widthwise direction of the inflatable
tubes, sticking edge of patch in place, working remainder down with slight pulling action so the injury is
closed. Do not trap air between patch and deicer surface.
c. LOOSE SURFACE PLY IN DEAD AREA (NON-INFLATABLE AREA). Peel and trim the loose
surface ply to the point where the adhesion of surface ply to the deicer is good.
1. Scrub (roughen) area in which surface ply is removed with steel wool. Scrubbing motion
must be parallel to cut edge of surface ply to prevent loosening it. Buff the edges of the adjoining surface
ply 1/2 inch with 74-451-75 buffing sticks, taper down to the tan rubber ply. Remove loose particles with
solvent and rag.
2. Cut a piece of surface ply material, Part No. 74-451-23, to cover the damaged area and
extend at least one inch beyond in all directions.
3. Mask off the damaged boot area 1/2 inch larger in length and width than the size of surface
ply patch. Apply one coat of cement, Part No. 74-451-11, to damaged area and one coat to patch. Allow
cement to set until tacky. Roll the surface ply to the deicer with 2 inch rubber roller, Part No. 74-451-74.
Roll edges with stitcher-roller, Part No. 74-451-73. Apply just enough tension on the surface ply when
rolling to prevent wrinkling, and be careful to prevent trapping air. If air blisters appear after surface ply is
applied, remove them with a hypodermic needle.
4.
Clean excess cement from deicer with solvent.
d. LOOSE SURFACE PLY IN TUBE AREA. Loose surface ply in tube area is usually an indication
of the deicer starting to flex fail. This type of failure is more easily detected in the form of a blister under
the surface ply when deicer is pressurized. If this type of damage (or void) is detected while still a small
blister (about 1/4 or 3/8 inch diameter) and patched immediately, the service life of the deicer will be
appreciably extended. Apply repair patch as outlined in paragraph a.
Reissued: 9/23/80
ACCESSORIES
AND UTILITIES
4G6