Extra 200 - Page 269

CHAPTER 51
PAGE 26
EXT
RA - FLUGZEUGBAU GmbH
SERVICE MANUAL EXTRA 200
PAGE DATE: 1. July 1996
If the extent of the damaged area exceed 10 cm (4 inches) a
large damage repair is required.
Carefully trim out the damaged portion to a circular or oval
shape.
Pre-laminate a backing plate from two layers of glass fibre
fabric and resin mixture, which must be approx. 20 mm
larger than the damaged area. Apply peel nylon fabric as
external layer. Sandwich the resin wetted layers between two
sheets of plastic foil.
Work the excess resin out and allow the plate to cure at
elevated room temperature for 8 hours on a flat surface or a
plasticfoil-covered surface of the proper curvature near the
damaged area, or the same location on a comparable
undamaged part.
Following the curing cycle remove plastic foil and peel
nylon fabric. Bond the backing plate to the inside using a
mixture of resin and cotton flocks, and adapt to the contour.
Cure the bonding at elevated room temperature for 8 hours.
Subsequently scarf the edges of the damaged portion with
sandpaper. Minimum length of scarf per fabric layer approx.
20 mm;
I M P O R T A N T Ratio (laminate thickness : scarf length) approx. 1: 50.
Following the scarf procedure, clean the repair area thor-
oughly:
- Remove the sanding dust with a pneumatic vacuum
cleaner
- Clean the scarfed overlaps with carbon-tetrachloride or
acetone in case of dirt or grease was introduced during the
preparation of the overlap.
I M P O R T A N T Repair area must be free of dirt, dust and grease.
Wet all surfaces of the backing plate and the scarfed area with
resin mixture. Lay on pre-laminated fabric layer in accord-
ance to the layer sequence plan. Ensure correct style and
direction of fabric.
REP
AIRS
Repair of Laminates