In article .com,
wrote:

Dick wrote:
In trying to restore an uncompleted, decades old project, some corrosion is
evident in the wing spars and as an old non-aero engineer, I would like to
know the basis or the process for evaluating it before proceeding.


Max limits we use is: 10% of the material thickness lost to corrosion
and you replace it. ie. if your part is .125", then if the material is
.1125" or less in any area, it gets replaced.

Craig C.


Usually, there is no corrosion under the lap joints of the spar. A
little phosphoric acid (Aluminum Jelly) applied, then washed off and
thoroughly dried should do the trick. I take it that the corrosion is
just surface corrosion, not intergrannular or filiform corrosion.

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