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From: whit@milton.acs.washington.edu (John Whitmore)
Newsgroups: sci.electronics
Subject: Re: tin plating aluminum?
Summary: aluminum solder and flux
Message-ID: <1283@milton.acs.washington.edu>
Date: 6 Jan 90 03:18:47 GMT
References: <11050@frog.UUCP>
Reply-To: whit@milton.acs.washington.edu (John Whitmore)
Organization: Univ of Washington, Seattle
Lines: 25
Organization:Physics Dept., University of Washington, Seattle

In article <11050@frog.UUCP> john@frog.UUCP (John Woods) writes:
>Is there any practical way of tin plating aluminum (i.e. Miniboxes) so that
>it may be soldered?  In particular, I just got some Datak TINNIT...

	Yes, tinning aluminum is relatively simple; we do it all the
time, with aluminum solder.  I have had good results with
Nassau/Rockmount "Neptune SS" solder and "Neptune Solder Flux", which
are used by brushing on the flux, heating the surface with a torch,
and adding solder when the flux bubbles.  The solder dislikes working,
so we often use this solder to tin the surface, then wash off the
flux (it's a fluoride flux, so USE ONLY WITH ADEQUATE VENTILATION),
and continue the soldering operation with lead/tin solder.
	Parenthetically, the same solder works on zinc, so it
is possible to solder a connection to a galvanized cold water pipe,
if you can drain the pipe aforehand.  It is simple to solder the
seams on a sheet-aluminum box to enhance the RF shielding, as well.
	It seems likely that TINNIT will work if and only if
the surface is cleaned of oxide, because it is an electroless
plating compound, and requires metal-electrolyte direct contact.
Additionally, I have tried fluxless aluminum solder (the hardware
store has it, packaged with instructions for do-it-yourselfers),
but never liked it much.  Flux helps a lot.

I am known for my brilliance,           John Whitmore
 by those who do not know me well.