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.