[R-390] Silver solder

[scott]

Thanks Dan,
I was referring to 2% silver solder in my initial post.  It works just like
regular solder.
I can hardly tell the difference when using it.  I just thought with so much
silver plating
in the receiver, that maybe there was a need for it on certain connections.

Scott



----- Original Message -----
From: "Dan Merz" <djmerz@3-cities.com>
To: "Jim Brannigan" <jbrannig@optonline.net>; "R-390 List"
<r-390@mailman.qth.net>
Sent: Monday, June 24, 2002 6:56 PM
Subject: Re: [R-390] Silver solder


> Hi,  in case anyone was confused by the term "silver solder",  as I was,
I
> might offer some clarifcation.  In my work experience,  which was largely
> metallurgy,  the term "silver solder" referred to a high melting
copper-zinc +
> some silver, a brazing alloy, that melts above 1100 deg F.  So I wondered
where
> this discussion was going to go.  I think this would be entirely out of
the
> question for radio wiring connections done in place on a chassis.
However,  I
> now remember that there is an electronic "silver solder" which is
basically
> 62/36/2 lead-tin-silver,  which I assume is the beast being discussed
here.  It
> has a slightly higher melting temperature, about  372 degrees F,  higher
than
> ordinary 63/37 lead-tin which is designed to have the  lowest melting
point
> (eutectic)  of 361 F for any lead-tin alloy.   Minor addition of silver
doesn't
> raise the ultimate melting temperature much and is still in the realm of
> temperatures that can be tolerated for on-chassis wiring.  One of the
cited
> advantages of this silver solder is better strength and less tendency to
> dissolve silver off  contacts when a connection is made to silver-coated
> metal.   Because it is off the eutectec composition (where everything
melts at
> once)  it will tend to exhibit a mushy melting characteristic and may be
more
> difficult to start melting because  very silver-rich regions may have
formed
> within it depending on how slowly it was solidified the last time it was
> melted.    For what it's worth........ Dan.
>
> Jim Brannigan wrote:
>
> > The only time I used Silver Solder in a radio was to connect a BNC to a
> > circuit board in an HT.
> > Flexing of the antenna kept breaking the tin/lead connection, silver
fixed
> > it.
> > With a good mechanical connection the strength of silver is
> > unnecessary.....and the additional heat to solder it undesirable.
> >
> > Jim
> >
> > > Is silver solder recomennded for any of the joints?
> > >
> > > I have just re-capped the AF module.  There are so many mechanical
grounds
> > > in this set!!  What makes it worse is the fact that the chassis is
> > aluminum.
> > > Aluminum oxidizes and makes for poor connections.  Aluminum wiring in
a
> > > building is an electricians dream--lots of service work.  A special
> > compound
> > > is now required for aluminum connections.  Why should this radio be
> > > different??  Boy it just looks like a lot of intermittent and hard to
> > trace
> > > problems in the making.  I am loosening all pertinent
> > > connections....applying Deoxit....then re-tightening.  Would seem
foolish
> > > not to while each module is on the workbench getting rebuilt.
> > >
> > >
> > > Scott
> >
> > _______________________________________________
> > R-390 mailing list
> > R-390@mailman.qth.net
> > http://mailman.qth.net/mailman/listinfo/r-390
>
> _______________________________________________
> R-390 mailing list
> R-390@mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/r-390