On 5/2/2012 3:55 PM, Dick Green WC1M wrote:
> 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?)
No, so far<:-)) I do the soldering of the PL-259 with the pin pointed
down, or at least at a steep angle. The solder will wick up the center
pin but only to the inside end of the pin. If soldered with the pin
pointed up (the usual way most do it) any excess solder will flow down
hill as far as the center conductor is hot enough to keep it liquid.
Another reason for either a temperature controlled iron, or get in and
out quick with a hot gun. If done properly the first should not add
enough heat to melt solder all the way to the dielectric. The second
involves learning the technique. Either way it is far safer to do the
soldering with the pin pointed down. Heat the pin right at the tip and
the solder will flow to the center conductor. Try to do so in a manner
that will not apply solder to the outside of the pin.
73
Roger (K8RI)
> 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@hotmail.com]
>> Sent: Wednesday, May 02, 2012 1:40 PM
>> To: amps@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@hotmail.com
>>
>>
>> ----------------------------------------
>>> Date: Wed, 2 May 2012 10:12:37 -0700
>>> From: k2vco.vic@gmail.com
>>> To: amps@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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