Instructions For Frp Repairs; General; Repairs Of A Frp Shell; Repairing The Outer Skin Of A Foam Sandwich Panel - DG Flugzeugbau LS4 Maintenance Manual

11.4 Instructions for FRP repairs

11.4.1 General

See also section 11.2 and 11.3.
Only materials listed in section 10 should be used.
Only damage defined in section 11.2 should be repaired.
Cut out damaged area, roughen the surrounding area for the overlap
required (see section 11.5).
Repairs should be made such that bonding is wet over dry. Specific details
concerning handling and using fibre reinforced plastics can be obtained
from various publications ie. "Petite Plane Patch Primer."
All repairs should be postcured for 20 hours at 54°C (129°F) before the
next take off.

11.4.2 Repairs of a FRP shell

Prepare the repair area as specified above. Scarf the shell so that the
individual layers of fabric can be seen like plywood layers. Remove the
gelcoat for at least 20 mm (.8 in.) around the damaged area.
New lay-up as shown on the sketch.
outside

11.4.3 Repairing the outer skin of a foam sandwich panel

Cut out the damaged area, remove the gelcoat over the overlap area +10
mm (0.4 in.) around the damaged area. Fill the damaged foam area with
resin thickened with microballoons (microballoons-resin), let harden. Sand
down.
Heat the area around the hole to approx. 60°C (140°F). Then tap the outer
skin with a round headed hammer so that the foam is somewhat
compressed. Apply the new cloth.
Issued: May 2011
Copyright DG Flugzeugbau GmbH - any copy or publishing prohibited
Manual valid with the up-to-date cover page only
Maintenance Manual LS4
11-4