Must this be done?
When is the best time; after all fitting and assembly or as the first step?
Are the steel parts(plunger tube, ejector, grip screws bushing) affected in the process?
Thanks in advance.
Since there have been no answers by those better qualified I will attempt to help you out. Aluminium will turn to aluminum oxide almost instantly in the presence of oxygen causing the whiteish silver coating seen on aluminum storm windows. The anodixing process prevents this and is also harder and more wear resistant than raw aluminum. I would do all fitting of parts and then remove all parts from the frame before sending it to a anodizer that specializes in firearms.
Yes Ron is correct, any steel left on will burn the alum away during anodizing.
there are 2 (probably more) commonly used anodize process
one is more decorative in that it is not hard per se but does protect against oxyodizing.
What you see on scope mounts mag wells and chamber checkers for instance. It bonds with the alum and works well but is not Tough.
Hard coat anodizing is Hard. What you see on 1911 and baretta frames for instance. It is much harder than the base metal ( over 65 rc iirc??) and is probably mandatory on feed ramps and rails for the alum to last. ( I think it involves a chiller in adition to the regular anodize and I would like to know more any help would be greatly apreciated)
I have not ever found a reliable source for hard coat anodizing frames (ffl required) but have only looked for 15 years.
I would really like to so if someone out there has a source please advise.
I'd spoken to Kurt Wickman a while back when I was investigating hard coat anodizing, and he advised that he'd found an aircraft industry vendor that provided the hardest anodizing he'd seen. Perhaps you could give Kurt a call.