I believe they use a hot dip process, much like hot dip galvanizing (simply put: you dip it in molten metal). An automotive engineer told me that it often replaces zink on parts where the temperature varies a lot (like on exhaust systems), as the thermal expansion of aluminum is more similar to steel. The hot dip method is a bit "sloppy" and not really suited for gun parts where close tolerances are needed.

For guns, I'd say that any application of metal needs to be done chemically or by electrolysis to be able to control the thickness and to get a perfectly uniform coat. I have never seen any of those processes used for aluminum, but it's just another metal so I guess it can be done?

Urrp - 2
 

Steinar,

Making fun of a man's pistol is worse than making fun of his wife; one can get you punched, the other can get you shot. Please realize my comment was meant in fun (before you put a 9mm hole in my rear!). (Actually, another 9mm hole; but that's another story.) Your lovely Luger sure is...unique. :cheers:

Best Regards,

John

Ollie,

Yes, that figures. That would mean that one could aluminize a steel piece first, to establish an aluminum outer surface which could, in turn, be worked carefully down to a desired smoothness, and then anodized purple!

An explanation for why Al is used rather than Zn for repeatedly heated and cooled components may lie in aluminum's higher ductility than zinc. Aluminum is generally softer than zinc, more ductile/less brittle. It would tend to hang on during dimensional fluctuations of the steel below, whereas zinc would tend more to crack off.

Absolutely no hard feeling. It's ment to bring out a smile at the range, just by beeing ..unique :)

If you could apply a very thin coat of aluminum, yes. I don't know if that's possible with aluminum though. The hot dip process will more than likely leave a coat that's too thick, and with some build-up in the nooks and crannies. I'm comparing with the problems you can have when using other metal coatings and if you compare with nickel, the only process that gives you a uniform coat is electroless plating. Even electrolysis can cause problems, as it won't cover evenly on irregular shapes. Then again, there might be a process that allows you to get an aluminum coat that's good enough for guns.

And you're probably right about the ductility. It has been quite a while since I discussed this with the engineer, but the problem with zinc is that it can start flaking if the metal underneath is expanding. This could very well be a matter of ductility rather than thermal expansion rate.

Well, I guess if you hafta do something like this, at least it's well done. Personally, I like a little Krylon flat black rattle can.

:jumper:

The more I look at it, the more I realize that I created something ugly as a mud fence..
Some times there should be a "undo" buttom in life :)

I don't think that it would be that difficult to "undo" that paint scheme if you so desired.....a bit of stripper, and away it goes.