Repairs to wing fabric?

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MI-Roger

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I took delivery of the wings, tail surfaces, and la ding gear of a LMA LM-1A two days ago. Delivery entailed trailering these components 120 miles to my Hangar space. Upon arrival I noticed a star shaped rear in the wing fabric, maybe 4 inches across.

What is the proper repair method? I am guessing that I need to change this star shaped rear into a circular hole to stop propogation, then cover the home with new fabric and dope. Is this valid? Recommended materials?

Thanks,
 

Dana

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Repair technique per AC43.13. Materials needed will depend on what covering system was used.
 

TFF

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You need to figure out the covering system. 43-13 is always right but the systems are usually easier because they figured out alternatives.
 

MI-Roger

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Well, it will be impossible to know the exact covering system. The wings were constructed by a now deceased individual, whose Estate donated them to a local EAA Chapter, which sold them to me as a Chapter fundraiser. At least they aren't painted. Any good source of photos of various covering systems that I can compare to the present material? The covering appears to be a finely woven fabric, not a polymer sheet.
 

pwood66889

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What kind of goop was hanging around that Estate? All the systems are about the same, but must be followed so the goops play well together.
If you cannot reliably determine the system, remove all the cover from the wing and do it all in what ever system strikes your fancy.
Again, the problem is if the goops react badly, you could end up in deep do-do.
 

MI-Roger

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If the interior of the fabric is pink there's a good chance it's polyfiber. If it's a blueish green then it might be Stewart's.

Edit: there are other systems but those are 2 of the more common ones.
Definitely a pinkish hue as it struck this newbie as slightly unusual. I have a set of plans forthcoming. Hopefully the original builder followed the designer's recommendations.

Or I can snip off some of the torn darts of fabric to test with different dope types.
 

Will Aldridge

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Definitely a pinkish hue as it struck this newbie as slightly unusual. I have a set of plans forthcoming. Hopefully the original builder followed the designer's recommendations.

Or I can snip off some of the torn darts of fabric to test with different dope types.
I'd say then that there is a very high degree of probability that it's polyfiber. I think (verify before testing) that acetone is the solvent used. Try some on the torn areas and see if it starts taking it off. The polyfiber manual is available from aircraft spruce (maybe online as well?) And is very straight forward. That's your official source on what to do and how to do it.
 

TFF

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MEK is the solvent for polyfiber. Should take off the pink. Top Coat may or may not be the same. Maybe auto or just about anything.
 

bmcj

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Also, when was this built? If built long ago, you can rule out some of the newer systems. However, yes, pink is usually a pretty good indicator of Stits Polyfiber. You since it is unpainted, you might also look for a manufacture stamp near some of the fabric edges.
 

Dana

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You can also use Stewart System to make repairs over anything else.
 

flywheel1935

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Hi, think we spoke some weeks ago ???
Anyway my LMA came with a fabric and glues supplied by "Blue River"about 30 years ago. may guess yours might be the same, will be covering mine soon with luck20200620_132412.jpg
 

MI-Roger

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Yes, we texted and e-mailed 6-8 weeks ago. I an not sure how old the work is on these wings. I will look for brand stamps on fabric edges. Can MEK even be purchased anymore?
 

MI-Roger

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Thanks. I knew that MEK was considered one of the nastiest of the nasty chemicals for user safety and the environment.
 

TFF

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Nasty does not mean unavailable.
In a professional setting where you are swimming in the stuff every day it can accumulate in your system. Hobbyists tend to go overboard on protection and will have limited lifetime exposure. Very little problem. If you live in Los Angles , you have other problems. It’s called driving to Arizona to get some; although you can go to Aircraft Spruce and get it.
 
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