[ARC5] [Milsurplus] [Vintage-Military-RADAR] Re: Mil Circular Material Questions

[J. Forster]

> I don't think so, John.  Mg darkens quickly in alloys with Al, and I
> haven't noticed that characteristic with the Cannon connectors in
> question unless they have had a very hard environmental life...then even
> Al darkens.

Well, on the ARB which is my current interest, the connectors are all
middle-dark grey

>> The etchant is either NaOH or KOH most like;ly...  both strong alkalis.
>
> Some are, but I prefer the phosphoric acid based specialty brands.

That's Aluminum Jelly.

> FWIW, mIne is Sherwin Williams Dual-Etch Metal Cleaner and Conditioner -
> W4K263.
>  A gallon lasts a long time since it is concentrated.  You do have to
> handle the parts with gloves...not so much for safety as to keep skin oils
> off the cleaned part until the self-passivation is substantially complete.

Ah! The latter makes sense.

-John

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