Technical data

13773-001
51-20
Page 930 Nov 2000
CAUTION: Ensure that size and shape of backing plate will not interfere with internal
structure or other systems.
Backing plate shall be approximately one-inch larger (0.5" overlap on each
side) than diameter of puncture if the backing plate is being bonded to back-
side of puncture. If impossible to bond backing plate to backside of punc-
ture, the backing plate must be sanded to form a scarf joint with a maximum
overlap of 0.25-inch before installing the backing plate on the topside of the
puncture.
Note: If impossible to bond backing plate to backside of puncture, the following
must be performed prior to installing backing plate to topside of puncture.
1
Sand the trimmed backing plate and the punctured laminate to form a scarf joint.
Backing plate should be flush or slightly recessed to the surrounding laminate when
placed on topside of puncture.
2
Trim the backing plate to a maximum overlap of 0.25-inch. Taper the edge to match
the taper on the laminate.
(g) Remove peel ply after backing plate has cured and been trimmed to final size.
(2) Backing Plate Installation
CAUTION: Ensure that size and shape of backing plate will not interfere with internal struc-
ture or other systems.
(a) Place the backing plate into position. Ensure backing plate will not interfere with any inter-
nal structure or other system.
Note: Backside of laminate and edge of backing plate must be prepared for bonding
before installing the backing plate.
(b) Remove the peel ply from backing plate (if present).
(c) Sand, remove loose debris with vacuum or clean compressed air, and solvent clean with
isopropyl alcohol. Allow adequate time for solvent to dry. (Refer to 20-30)
(d) Bond backing plate to laminate with Devcon 5 Minute Epoxy.
Note: If difficult to manipulate backing plate into place, hold plate in place with
temporary fasteners (tape or hot glue) to attach a temporary handle.
(e) Remove fasteners and sand off any protruding ridges of adhesives.
(f) Grind the taper to a smooth transition between the backing plate and laminate, avoid
grinding the backing plate.