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What do you use to solder connectors onto bulk coax cable?

Soldering the UHF connector to the coax shield on a PL-259 is described as requiring a bit of "experience and skill" in Dave Casler's video.

UHF Connectors 274

The trick is to solder through the four holes in the connector shield to the braid by getting it hot enough for the solder to flow properly - but at the same time, it must be done quickly enough so that the dielectric inside the coax cable doesn't melt and allow the inner conductor to migrate.

Yes, I know that I can buy 'ready-made' cables and that I could use 'crimp-on' connectors but I don't trust them after having bad experiences in the past. An example is crimping a Sta Kon ring connector onto a wire. It makes a good mechanical attachment but over time a high electrical resistance will often develop.

One thing that Dave doesn't mention in his video (besides experience and skill) is that putting one of these connectors on successfully also requires the use of a suitable tool - in this case, most probably a soldering iron.

So what have you used to do this job properly?

I have used Weller soldering guns of various wattage, soldering irons of different sizes and have even tried a butane torch. Too small of an element and all the heat of the tip is consumed before the connector gets hot enough to flow solder - and waiting for it to heat back up melts the coax!

UG-176 cable adapter

The Weller guns don't have much thermal mass in the tip and so they seem to take much too long to get the connector hot - and it melts the coax!

I watched a ham install a connector in his shop one time and he did a marvelous job... BUT - his tool of choice was an old and huge soldering iron that'd been passed down to him from his father and he wasn't willing to sell it.

So what kind of tool have you successfully used that you recommend for the job?

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    $\begingroup$ I'm interested in answers to this question too but it as-is it might run into problems versus the StackExchange Q&A policies. (Specifically it's pretty close to asking for "product recommendations", and might also attract anecdote/opinion–based discussion.) But I'm not going to flag it, because I think at its core there is a solid and important question to be answered here. Maybe it could be spun a slightly different way perhaps, de-emphasizing the "what would you personally buy?" and playing up the "what's the required process for these components?" angle. $\endgroup$ Apr 8 at 20:42
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    $\begingroup$ I hear you, but I think he's looking for legit info... a low heat iron, a high heat iron, a soldering gun, appropriate shaped tips, etc. "what kind" is a legit q IMHO $\endgroup$
    – webmarc
    Apr 8 at 22:18
  • $\begingroup$ Yeah, the "what kind" makes this one OK in my book. There are many kinds of soldering irons, and the most popular answer suggests crimping. So I don't see this as a "shopping" question looking for a specific soldering iron. $\endgroup$
    – Scott Earle
    Apr 13 at 10:12

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I'm going to answer a slightly different question to the one asked... I promise not to be offended if it's ignored or even downvoted (if it receives enough downvotes, I'll delete):

Crimping, with the right tools, can be superior to soldering.

This is contrary to what I learned from my dad and many others growing up, that soldering is king. But it turns out that with the right tools in hand, crimping creates both the needed physical bonding required AND provides some marginal mechanical improvements.

Some sources:

All this to say, in my particular operating environment, I've had great and long-lived success with well crimped connections coupled with appropriate weatherproofing measures.

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    $\begingroup$ I know in Formula 1 they don't solder connectors onto wires as the point at which the solder ends is a stress concentrator, that, with the vibration in the system, leads to broken wires. The 'cold weld' or crimp everything. $\endgroup$ Apr 12 at 17:39
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    $\begingroup$ I worked with Boeing on the 777 and they crimped every connector on the airplane. $\endgroup$
    – pidloop
    Apr 12 at 20:52
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It looks like you may be trying to solder to the reducer rather than the actual connector. If that is the case, try soldering to the connector through the openings in between the threading designed for the screw cap.

PL-259 Connector Soldering guide

The other tip that I've been given is that using a larger sized tip for a soldering iron (not sure if the Weller Solder Gun has replaceable tips, my experience has been with irons) allows a faster transfer of heat and can melt the solder more quickly into the desired location.

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Crimping works well. The centre pin still needs to be soldered but that is easy in comparison.

My favourite iron for soldering PL259 is an old brute with a tip that weighs several ounces. The size of the connector will cool smaller irons too much, and this one, while taking several minutes to heat up, does the job quite quickly which is the objective. It is much more effective than my soldering gun (100/140), although at hamfests there are larger wattage units that I've heard work well.

I've also seen it recommended to make the holes a little bigger to make it easier to flow the solder in, but with the big iron the solder flows in just fine.

73, Chris

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