Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!apple!xanadu!michael
From: michael@xanadu.com (Michael McClary)
Newsgroups: sci.electronics
Subject: Re: tin plating aluminum?
Message-ID: <1990Feb2.141035.11149@xanadu.com>
Date: 2 Feb 90 14:10:35 GMT
References: <11050@frog.UUCP> <21000054@m.cs.uiuc.edu> <5051@ptsfa.PacBell.COM>
Reply-To: michael@xanadu.UUCP (Michael McClary)
Organization: Xanadu Operating Company, Palo Alto, CA
Lines: 26

Regarding soldering to aluminum:

About two decades ago I was working as a techie in a radar
lab, and asserted that I could solder aluminum with ordinary
rosin-flux 60/40.  (I'd figured out the trick, and practiced
in advance, so I knew it would work.  The professors in charge
of the lab, though "knew" it couldn't be done, and got quite
a surprise when I did it.)

I took some 4" or so aluminum strip, bent the last 1/4"
90 degrees, and clamped it in a vise with the surface to
be tinned horizontal.  Took a big pyrimidial iron (to have
enough heat), laid a BIG blob of solder on the edge, put
the iron tip under the blob, and scratched the oxide off.
Took several minutes.  The blob kept new oxygen away, and
tinned the aluminum as soon as the oxide was gone.

After doing this to two strips, I sweated them together.
Profs weren't convinced it was a real joint until I took
visegrips and peeled it apart - which didn't happen until
the strips were bent in almost a half-circle.

The hard part is getting the aluminum hot enough to tin.
It conducts the heat away VERY well.

These fluoride fluxes sound a LOT easier.