On Tuesday, December 1, 2015 at 9:23:11 AM UTC-5, N_Cook wrote:
On 01/12/2015 14:00, N_Cook wrote:
Pure tin tinning on a component which should have had derogated Pb/Sn

If I were to render an opinion, pure tin as a mechanical joint is a very bad idea, nor would I think that a sophisticated manufacturer would do that as a matter of intent. Pure tin is extremely brittle, and should NEVER be depended upon in any sort of situation where mechanical stresses (expansion/contraction/flexing) will take place. Add to this the whole issue of tin whiskers (which NASA, at least now understands all too painfully). If what you suggest is accurate, this is a design flaw of significant magnitude. If it is present fleet-wide, it is time to ground these beasts until the problem is addressed specifically.

I would hope that aircraft manufacturers by now would have learned that some admixture to their solders is a necessary step to reliability. And would have learned by now from the Nuclear industry if not NASA that relying on pure tin is a dangerous practice.

All-and-at-the-same-time, counterfeit parts are getting into the OEM repair stream at every level. It would not be difficult to believe where such parts may get into the OEM first-install stream as well.

Peter Wieck
Melrose Park, PA