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From: irwin@m.cs.uiuc.edu
Newsgroups: sci.electronics
Subject: Re: tin plating aluminum?
Message-ID: <21000054@m.cs.uiuc.edu>
Date: 12 Jan 90 01:39:38 GMT
References: <11050@frog.UUCP>
Lines: 46
Nf-ID: #R:frog.UUCP:11050:m.cs.uiuc.edu:21000054:000:2230
Nf-From: m.cs.uiuc.edu!irwin    Jan 11 16:24:00 1990


/* Written  3:30 pm  Jan  5, 1990 by john@frog.UUCP in m.cs.uiuc.edu:sci.electronics */
/* ---------- "tin plating aluminum?" ---------- */
>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 (a solution
>for tin-plating PC boards); the ad copy claimed that it "tends to plate any
>metal more active than tin", so I wonder if it will work on aluminum (though
>I suppose the oxide coating is likely to defeat this, and even if not, I don't
>know if the resulting coat would be usable).
>-- 
>John Woods, Charles River Data Systems, Framingham MA, (508) 626-1101
>...!decvax!frog!john, john@frog.UUCP, ...!mit-eddie!jfw, jfw@eddie.mit.edu

>Happiness is Planet Earth in your rear-view mirror.	- Sam Hurt
/* End of text from m.cs.uiuc.edu:sci.electronics */

Many moons ago, in fact in the mid '60s, I designed and built some
RF systems for the University of Illinois Athletics Department, such
that they could record the heart and respiration rate of an athlete
running around a half mile track.

The athlete wore a unit battery operated about the size of a pack of
cigarettes that had electrodes, etc. The receivers were placed internal
to a VM (Voice of Music) tape recorder and were built in a minibox
about 2" X 2" X 10". These were aluminum boxes. At the time I built
them, I had need to ground to the box at various points to prevent
stray loops at high frequency. I located a flux that came in a tube
like tooth paste. One cleaned the contact point with aluminum wool,
applied the flux and then tinned it. After the initial tinning, a
rosin core solder worked very well on it.

This has been 25 years ago, and I am sorry to say, I do not remember
the name of the product. The point of my response here is to say that
it has been done, probably can be still done, if you can locate the
correct type of flux.

For the curious, the rates were tone encoded, put on reel to reel
tape, and the tape was then played into a tone to punch card (what
are those :-)) converter. The cards were loaded into a computer to
do studies on the abilities of the athletes.

Al Irwin, E.E.
Univ of Illinois
Dept of Comp Sci
Urbana, IL
irwin@m.cs.uiuc.edu