Putty/epoxy cement for aero applications

[waqasmalik]

Hi all, recently i completed a project for a company who deals with planes. Unfortunately, there came a pit on the outer surface of the part.. The part is going to fly in air so aerodynamicaly its not acceptable. What i did was that i filled that pit with putty used for painting but the company engineer demands some tests to demonstrate that it will be safe during flight and some other assurances regarding its adhesion with metal which is aluminum obviously.
Is there any recommended test/ standard/ article/ practices which could guide me how to solve this problem? Any help will be highly appreciated.
Thank you in advance

 

[KENAT]

I believe there should be aerospace grade body filler - we certainly used filler at at a former employer on air borne items though they were of short life.

What I'm less sure of is if at some point we'd qualified the filler in that application or if it was a case that if applied in accordance with the manufactures instructions it was qualified by their approval.

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(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[KENAT]

BTW, may be a better question for an aero forum.

http://www.eng-tips.com/threadcategory.cfm?lev2=3

http://www.eng-tips.com/threadcategory.cfm?lev2=4

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[tbuelna]

In the aerospace industry, your customer's PO should have included a set of requirements (such as drawings or written specifications) that defined things like surface roughness of metal components. If the size of defect in the surface of the metal part in question exceeded the customer's requirements, normal aerospace industry practice would be for you to submit an NCR to your customer and request corrective action. On the other hand, if this type of situation was not covered by terms of the PO, you have no formal obligation to comply with the company engineer's demands.

The problem you have is that unless you have thorough documentation of everything involved in the rework process there is no practical way to prove the quality or properties of the repair. The only option would be to remove the existing patch and repair it again using a controlled/validated process and materials, plus documenting anything required for QA purposes. Once you have documentation that the repair was performed in accordance with a controlled process and using specific materials, you can demonstrate by analysis that this repair will have certain minimum properties.