[Amps] brittle shields? and soldering vs crimping

[Dick Green WC1M]

Allow me to clarify. The joint becomes brittle, not the material. I think
what happens is that the solder penetrates the entire braid, from surface to
dielectric, fixing the strands in place. As the coax entering the connector
bends and twists (e.g., from whipping in the wind when hanging from a
balun), the strands bend back and forth, then eventually snap. This can
probably happen with a crimp connector, but in that case the ferule is
pressed against the surface of the braid only, and the inner strands can
flex more easily.

At least, that's my uneducated theory, based on examining failed connectors.

One has to be careful when soldering the center conductor, too, especially
with foam dielectric and especially with large tubular center pins like on
PL-259s (ever had the solder flow all the way down the tube to the
dielectric and shield braid?) I think the combination crimp/solder center
pin on a crimp N-connector minimizes the chances of overheating the center
conductor because the crimp gives you some mechanical clamping and you only
need minimal solder to make the connection through the tiny access hole.

73, Dick WC1M

> -----Original Message-----
> From: Charles Harpole [mailto:k4vud at hotmail.com]
> Sent: Wednesday, May 02, 2012 1:40 PM
> To: amps at contesting.com
> Subject: [Amps] brittle shields? and soldering vs crimping
> 
> 
> Has anyone on Planet Earth ever heard of copper or tined copper
> "becoming brittle" due to heat?
> 
> 
> 
> And what about the report of not soldering the center conductor because
> of the use of high power and  70 ohm coax?
> 
> 
> 
> Was I naping when some passed the ham test?   73,
> 
> 
> 
> Charles Harpole
> k4vud at hotmail.com
> 
> 
> ----------------------------------------
> > Date: Wed, 2 May 2012 10:12:37 -0700
> > From: k2vco.vic at gmail.com
> > To: amps at contesting.com
> > Subject: Re: [Amps] soldering vs crimping
> >
> > It's not tricky if you have three things:
> >
> > 1) The right soldering iron. I have a Weller W100P that I use for
> > this. It's also handy for copper tubing and strap in tank circuits,
> > etc. It has a large thermal mass so that the heat is transferred to
> the connector quickly, and is also temperature controlled.
> >
> > 2) Decent connectors. You need these anyway! I have some that I
> > inherited that solder doesn't stick to.
> >
> > 3) Decent coax, with good braid coverage. Again, you need this anyway.
> >
> > On 5/2/2012 9:51 AM, Dick Green WC1M wrote:
> > > I'm with Carl on this one. Actually, the crimp N-connectors I use
> > > have center pins designed to be crimped *and* soldered -- there's a
> > > little hole in the side for soldering. I've found that there's so
> > > much variation in center conductor size that crimping *and*
> > > soldering makes for the most secure connection. The UHF crimp
> > > connectors I use all require soldering for the center conductor --
> > > you can't crimp it. As for the shield, there's no question in my
> > > mind that crimping is superior to soldering. It's very difficult to
> > > properly solder shield braid without overheating it and melting the
> dielectric. I'm not saying it can't be done -- only that it's tricky.
> > > I've only had a few solder connector failures over the years, but
> > > they've all involved either deformation of the dielectric due to
> > > overheating, or breaking of the shield because it became brittle
> after soldering.
> > >
> > > 73, Dick WC1M
> >
> >
> > --
> > Vic, K2VCO
> > Fresno CA
> > http://www.qsl.net/k2vco/
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