Extra 300/SC, Maintenance Manual

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CHAPTER 51
PAGE 22
MAINTENANCE MANUAL EXTRA 300/SC
PAGE DATE: 12. February 2019
51-70-02 Repair of Sandwich Material
Two types of core materials are used for sandwich on the
EXTRA 300/SC:
- PVC hard foam
- Honeycomb
both with glass or carbon fibre shells
The following section describes the repair of both types of
sandwich. Different processing techniques for these mate-
rials, if necessary, are also described.
a) Minor surface damage
Around a visible crack, the laminate may be separated from
the core material. Determine the extent of this area by coin
tapping. Remove the separated laminate carefully using a
sanding disk, sanding block or a sharp knife. Prepare a
scarfed overlap of the laminate around the damaged area.
Overlap lenght per fabric layer min. 20 mm;
I M P O R T A N T Ratio (laminate thickness : overlay lenght) min. 1: 50
(refer to Figure 5).
Figure 5 Minor surface damage
After preparing the scarfed overlap, clean the repair area
thoroughly as follows:
- 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.
Damaged core material has to refilled with a mixture of resin
and microballoons (weight ratio 100:15). Apply resin mixture
REPAIRS