Corrosion is a strange beast, to repair the above, first replace the
damaged part, treat the new part in a alochrome solution, then zinc
chromate primer, and a final epoxy finish coat. should stop it
re-occuring. I dont know much about fabric construction, but can fabric
coverings be bonded over epoxy painted and treated parts??
sever corrosion we are finding on hawks is caused by Rubber! the rubber
seals on the overwing fairings are causing a sever corrosive reaction,
to a point of total destruction of the part within a year! yet the
metal not in contact with the rubber is in new condition! the rubber
strip is solid riveted between a metal skin and metal backing strip,
and the corrosion only occurs where the rivets press the 3 components
together. all know treatemtns have been tried and all have failed to
stop it. (yet the RAAF wont allow us to chage the rubbertype)
3 aircraft in teh fleet were test flown before being painted! and as you would expext, all 3 are showing signs of corrosion (to damaging levels) in just 5 yrs of life, where the other aircraft are relativly corrosion free.
so be sure to have your aircraft primed and finish coated before any test flying!
Unfortunaetly if using the zinc chromate primer, the MEK (methyl Ethyl Ketone) will attack it and dissolve even if under 2 pack expoxy primer topcoat.
Alodine treatment, 2 pack expoxy primer and topcoat of 2 pack paint with flexi agent (or buy the certified product $$$)
paint adhesive to surface, lay fabric, brush with MEK push into fabric,
heat tighten put on strengthening tapes, clips/screws/rivets/tie fabric
to ribs, finishing tapes, drains, inspections holes etc seal fabric,
more dope, silver dope, then epoxy primer (with flex agent) then top coat (flex agent) the last painting steps are NOT certified after the silver, but the standard coloured dopes look crook. (ceconite system, available locally) Other systems e.g. aeroflite exclusively use epoxy and urethane.
like a lot, it is, but the results can be stunning with modern paints.
Especially as you can actually wet sand the fabric coatsto absolute
flatness. And if done correctly, unlimited lifespan.