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  #11  
Old 09-26-2017, 02:41 PM
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We have had problems on ours which resulted in us re painting the whole airframe after 5 years. Initially along seams on the wings - particularly behind the tanks where internal condensation is greatest. Then on ailerons and finally on the fuselage lap joints behind the canopy. The empennage is as good as new.... The aeroplane was finished in Mipa 2k auto paint (German), etch primed, base primed and top coated. It was a reasonable coat but not as heavy as I have seen on some aeroplanes. Personally, I would have tackled the local areas, but I was overruled by the group and one member volunteered to strip the aeroplane and had access to a professional car shop at a very advantageous price

I have seen maybe 5 or 6 cases in the UK where tin worm is starting from lap joints.

That said, all kits are different and are prepped differently.

What I am saying is the problem is coming from within the structure, not from without because the tracks start at the joint and work outwards. Those who have taken the time to fully prime mating surfaces on slow build kits will probably not be affected as we have seen on our empennage.

It isn't going to happen to all, it isn't going to particularly affect amateur painted aeroplanes, but the evidence is there. I think a relatively inexpensive application of a suitable spray corrosion inhibiter should stop it completely.

Location will be bound to affect it - we are in a warm, cold damp ish environment away from the coast but we get big temperature changes in the hangar and see condensation a lot.

Don't panic, but awareness will always help prevent an occurence and after all, we love our aeroplanes and want them to last a long time.

Our RV14 is a slow build kit and is getting fully primed on mating surfaces. It will also be sprayed with ACF50 on completion.
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  #12  
Old 09-26-2017, 02:59 PM
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I presume Tin Worm corrosion is the UK term for Filiform Corrosion?



Is that the case?
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  #13  
Old 09-26-2017, 03:54 PM
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Yes, that is the nasty stuff !

Colloquialism I guess
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  #14  
Old 09-26-2017, 09:33 PM
Bavafa Bavafa is online now
 
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Quote:
Originally Posted by mike newall View Post
Whatever you do end up with, if you have a QB kit, make sure once it is painted and cured you get some ACF50 or Corrosion X into as many places as you can.

The factory wash primer is definitely not enough and we are seeing too many examples of lap joint tin worm on QB structures after a couple of years.
The paint job on my 7A which was from a quick build kit was like new after 8 years. The only paint issues I had was some minor chip on the wheel pants from rain.
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  #15  
Old 10-16-2017, 03:12 PM
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Another thing to look for on a QB is what ever oil base stuff they put on these things for corrosion prevention for the boat ride back needs to be cleaned out of every lap joint. I discovered this after my first primer coat, the wings were mechanical scrubbed with maroon scotchbrite and dawn soap-water mix, water rinse, grease and wax remover and that was not enough, I went back and used brake clean followed with compressed air at all the lap joints and started all over. Also ask what length of time each piece of aluminum will see from prep to primer, corrosion starts in a few hours and will cause adhesion problems. I also did the green lock tite trick on the tank rivets and pulled a vacuum, been painted 4 years now, so far so good!
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