Grob Astir CS G102, Руководство по эксплуатации самолета

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REPAIR INSTRUCTION ASTIR CS
Rev. 9 28. Nov. 2005
9
Repair of styrene-foam supported parts
Repair shall be done in analogy to repair of GRP hard foam structure. Styrene foam
has an impermeable surface, filling of surface pores is not necessary, the fibre cloth is
held in position with pure or slightly thickened resin. With large damage let layers cure
one at a time to avoid wrinkling.
Warning: Do not use strong heat to speed up curing time, styrene foam may develop
blisters thus rendering the repair useless.
Repair of GRP laminate parts
Repair to GRP laminate is simple. Splice the area around the damaged section, position
fibre cloth in layers (largest patch first), after 2-3 hours, when the resin has partially cured
smoothen area with resin and micro balloons. Splice length per layer approximately
20mm. Ratio of laminate thickness / splice length approximately1:50. In case the splice
area is contaminated clean with Carbon Tetrachloride or Acetone. With large damage a
underlying support (plywood) should be used. Wet laminate should not bridge a gap of
more than 20 mm unsupported. The plywood support can be held in place with glue and
nails (e. g. metal fitting in
fuselage) which can be removed afterwards (Figure 4).
Paint-Work
As soon as the laminate of the repaired section has cured, it can be ground roughly
with (80 grit) sandpaper. Uneven spots must be filled and smoothed with white polyester
filler. Grind with fine dry-grinding paper (150 grit) until a moderately smooth outer surface
is produced. Before painting, the repaired section must be cleaned from grinding dust,
residue or other foreign bodies.
When applying Gel-Coat (Schwabbellack) + hardener use a moderately stiff paint brush,
put on several thin layers, until the laminate can no longer be seen. The individual layers
should be allowed to harden and then ground with (360 grit wet paper), additional
layers should then be added and likewise ground.
The final finish should be carried out with 600 grit or 800 grit dry and wet grinding paper
and then polished with a silicon-free car polish or with hard-wax, using a polishing
machine.