[Milsurplus] Satin finishing aluminum

Mon, 28 Oct 2002 14:31:59 +0200

where was zinc chromite, or chromate, used?

I also thought that gave a greenish-yellow color
to aluminum.

73
Sheldon
WA4MZZ

[email protected] wrote:

> Al
> Years ago when working at Microwave Semiconductor Corp. we used a product
> called Irrodite to protect aluminum.  A kit came in quart paint style
> cans as a dry powder.  One was used as a cleaner (caustic?) and the other
> was the conversion coating.  The complete kit was mixed and stored in
> plastic gallon containers, one for each solution.  Used for months until
> solution was depleted.  I would guess either MacMaster-Carr or a
> laboratory supply house would have it.  If I have spelled Irrodite right,
> a Google search should turn up some information.
> Regards
> Jim
>
> On Sun, 27 Oct 2002 21:52:32 -0500 Al Klase <[email protected]>
> writes:
> > [email protected] wrote:
> >
> > > The yellowish aluminum seen in a lot of military stuff is the
> > result
> > > of a "chromate conversion coating" but I don't know any more about
> > it.
> > >
> >
> > Yes, sodium hydroxide will get you a satin finish, but
> > that's the easy part.  For long life some kind of protective
> > finish is required.  Most commercial stuff gets a
> > "conversion coating" of some sort.  I was involve with this
> > years ago.  After the etch and rinse the work is dunked in a
> > second solution and rinsed again. This prevents corrosion
> > and finget printing etc.  There are clear ones as well as
> > the yellow mentioned above.  Two trade names I know of are
> > "Alodyne" and "Clear Coat."
> > The $64 question is where to get the chemicals in small
> > quantities.
> >
> > Regards,
> > Al
> >
> >
> > --
> > Al Klase - N3FRQ
> > [email protected]
> > Flemington, NJ 08822
> > Web Page:  http://www.webex.net/~skywaves/home.htm
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> >
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