>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.
Sealing restores the fatigue strength, but, it also cancels the excellent
bonding with epoxy.
Pure speculation now. My guess is that when epoxy bonds with unsealed
anodised alumium it might well restore fatigue strength too. However with
the bonded in parts you would need to paint the whole of the part with
epoxy. Just a 2 pence thought.
graham
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