In article <0.59bbd9ec.2560481a@aol.com>, Fillinger@aol.com () wrote:
> Note that some builders have commercially anodized the aluminum parts.
> I can't say how much better this is; they may add to this thread. But
> aluminum corrosion is an electrolytic process, and can occur buried in
> resin and thus in the absence of air (but latter also promotes it --
> e.g., acid or salty atmosphere). A clean, rough surface is probably
> the most important thing to have.
>
> Regards,
> Fred Fillinger, A063
Fwiw I anodised my bits! It wasn't too painful - or expensive. It is
important to use the right process though - Chromic not sulphuric. If you
specify the correct DEFSTAN (which Andy Draper can tell you; I have long
since forgotten I am afraid) you can be sure the job will be done right.
Chromic only treats to a depth of about 2 microns whereas sulphuric goes
much deeper and forms a hard but brittle surface which will reduce the
fatigue resistance of the part. I was advised to have the parts sealed but
again I cant remember why, but no doubt the Anodizer could give the
reason. Whether this is any better than Alodyne I don't know, but I do
remember that Alodyne didn't cost much less than letting a professional do
the job for me so I put my faith in anodizing.
Paul Atkinson
|