I'm assembling a PL259 plug for use with coax cable. Not done it before. The instructions that I have, say that the braid on the coax should be soldered to the plug body (i.e. the bit with the pin on it), through the solder holes. However, I'm having difficulty getting the solder to wet the plug body, I think because the latter just isn't getting hot enough. I'm using a 100W solder gun (the sort with a hairpin element that heats 'instantly'), cored solder and additional flux. I'm beginning to think I need a blow-torch! But the instructions also say not to used excessive heat, and I'm worried that I'm going to melt the plastic insulator that holds the central pin.
Is there a technique with these things, or can anyone give me some tips as to what I should be doing?
Give it a good scrape with a file, and apply some flux. Tin with solder before threading the bread. Personally I like to use a crimp-on BNC plus BNC to PL259 adapter.
Cheap PL259s are usually chromed, which makes a *really* good surface to solder to. Not. I usually file off a good area around hole before trying to solder them.
Remember that these things are valve era, when soldering irons were bigger.
There are three ways to asemble these. Few can agree on the best! Do you solder the braid at all? Do you solder the braid to the inner sleeve and risk damaging the dielectric by overheating it? Do you solder through the outside body of the plug and risk a poorly heated joint that's at risk of being dry? Personally I go for soldering from the outside: More demanding of iron, but less risk.
The crucial bit is that before you go near the cable, clean the plating around the outside of the plug body at the soldering holes and tin this area. If the connectors are chromed, it's a swine to solder otherwise (although you _can_ do it, with a 1940s flux).
After you've folded the braid back over the central tube, _don't_ be tempted to solder it. This is how you melt the central dielectric.
Soldering the central core is easy. So don't do it yet, get the awkward braid done first, Just In Case.
After you've screwed the centre in, it's time to solder the braid. This is easy, because you pre-tinned the shell, didn't you?! You need plenty of heat, but not too much. You need to heat the shell, but avoid transferring heat to the braid too much, or again you can damage the dielectric. Just enough solder to retain the cable (remember that this is the only strain relief too!), not enough solder to fill the holes up flush! The trick is a _heavy_ iron (high short-term capacity) more than a powerful one. You need to get the job done quickly, before too much heat is conducted into the braid.
A search for PL-213BC PL-259 Plug Large Entry with Pressure Sleeve on Waters and Stanton's site brings up the following.
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likelihood of success when fitting these is much better than the one you describe, but make sure they are as shown in the picture and not similar ones that have a slightly different method that relies on a smaller metal washer.
If you have to use the one you describe I have had reasonable success in tinning the braid before fitting into the plug, that way you don't have to apply heat for quite as long. Clean, file, the body of your plug and tin it before assembly too.
PL259s are the work of the devil anyway, not much more than a shielded banana plug.
Thanks for those tips. It seems that a key step is to remove the chrome plating before tinning the shell, which I hadn't done. I was attempting to tin the shell before doing anything with the cable itself, as I had a feeling it would be difficult, and I failed miserably!
I have, in the dim and distant past, soldered them using a Taymar blowtorch fitted with a big chisel soldering iron tip but as others have said, you do need to remove the nasty shiny plating unless you are fortunate enough to find good quality plugs like Amphenol.
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