Soldering XLR


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Wolf mentioned at some time that he might be posting a tutorial on soldering. I would like to open up a dialog on soldering skills to see how others do so and any tips or techniques they have.

Let me start it out. I am not to do the heat shrink over the terminal trick unless the wires are stripped too long and are near the strain relief on XLR/DMX cable. I also have problems with the heat shrink shrinking before I can move it when I do proper soldering. The only time thus that I attempt this is on Scroller cable when 120v is running thru the XLR plug.

Since I have not been able to master that technique, I have my own style that works but is not text book. I find my solder station best set between 650°F and 700°F with 0.050" acid core solder. I find that less temp. does not heat up fast enough, and more temp. melts stuff too fast. The actual end product is good - not cold solder joints, melted plastic around the terminals etc.

Where melting is concerned, any thermoplastic insulation on the wire melts far too fast, no matter how quick or careful I am at it. By the time the solder has cooled, at least 1/16" of insulation has melted on a good day. That’s a bad thing so for my technique, I use clear heat shrink one size larger than the insulation such as 3/64" and don’t shrink it before it gets soldered. Instead, the heat on the insulation convects and cools the insulation so it does not melt the wire’s insulation shorter, while shrinking the heat shrink around the insulation which also adds extra insulation to it. Rubberized or neoprene insulation gets no heat shrink because it does not melt, but most DMX rated wire is thermoplastic. In either case, the stripped wire goes directly into the terminal without any heat shrink covering the outside of the terminal - the solder on the terminals is exposed. Such insulation over the terminals melts before it can be moved anyway should it be attempted and I have to do a time consuming needle nose pliers trick to move it afterwards. That’s given the wire has been stripped back long enough to get the heat away from the outer covering sufficiently. What do you use for this? Some kind of spaghetti tubing or higher temperature shrinking heat shrink?

I kind of figure that as long as the insulation stops directly at the terminal if not recessed into it, there is no chance of a short, but it’s not text book or what I see most people doing. If the cable comes from a factory, it’s usually perfect. If anyone I know or in cable that’s less than factory, the heat shrink over the terminals is usually attempted but either too much of the jacket has been stripped off and the strain relief fails, or the insulation is melted and too much bare wire is exposed - sometimes even coming out of the over coating on the terminal. When other techniques are used, they don’t work either. How does one do the insulation over terminals on properly made XLR cable?

Thus my problem. The instructions on XLR connectors say you need to strip back 5/8" of jacket on the wire, and if you do more, it will slip out of the strain relief. You are stripping the insulation off 1/8" of each wire which leaves ½" of insulation left to insert at least 5/16" of heat shrink to cover the terminal. Can’t be done without melting the heat shrink. Plus given the temperature, thermoplastic insulation melts far too easily, yet I don’t see any professionally done cable using this technique or having problems with the insulation melting too far. What am I missing?
Thanks for sharing your tips--I'll try to address some of the heat-shrink tricks I have learned and how to do it and get away with out the shrink shrinking too much... Mostly--it involves the size of the shrink and the high-temp PVC jacket style shrink I use--not the plastic. Another factor happens to be the temp I use on the iron if I am shrinking--and tinning the tips of the iron and the wires you will be soldering too. Plus a few other tricks to the stripping back of the wires for the strain relief--there are 4-5 soldering methods I have picked up that work in specific instances for short or long strippings..and doing a "wrap" of shrink that is secondary to the exposed area under strain relief. I'll see about adding those details to the tutorial...hopefully I will be able to post good example pics that are clear. For basic "gotta solder this and go" type of deals--its pretty straight forward but I wanted to show a bunch of different techniques that people can do--since there is no "one" golden all around method I believe, and hope to hear others techniques that I may learn from and improve on mine. This website is all about sharing knowledge in tech...not about one "this is the only way" type of thinking to do something.

Thanks for your input Ship--as always its appreciated..I'll hopefully be able to work on the pics and tutorial soon...

When we have to make repairs in the field on XLRs we use a Weller 100/140 watt pistol grip gun & Kester multi core solder (rosen core is prefered for ALL electrical connections) acid core is for sheet metal & hobby work , 1st heat the gun on high , hold theXLR with needle nose & heat 1 connector a time, while the connector is hot sling the old solder out. (use safty Glasses ok) After all are clean place the connector in a socket from a rachet set that will hold it snug, We then heat the connector on high till it just starts to smoke then let of to low, insert the stripped wire, apply the solder, repete till all are finished. If you strip the wire so no bare copper is showing out of the solder pocket your done. We never use shrink wrap & never have problems with our solder joints. Its the factory made ones you gotta fix :wink:
I tin each wire with rosin-core solder, then let it cool before sliding my little piece of heatshrink over it. I melt a little solder into the solder cup, then push the already-tinned wire into the molten solder, put down the soldering iron, pick up my long-nosed pliers and grab the solder cup with the pliers, to cool it before the heat can get to the heat-shrink tubing. It takes a little practice, but I can turn out XLR's that look like they were done in the factory (better than some factory installations I've seen).

Funny this topic should crop up now.... ive just been building an FM Transmitter that I have built and solderd completely from scratch.
I use a a 50watt nelson soldering iron for this, but also have a solder gun that goes up to 300watts. It is one of the ones like a glue gun, that pulls through the solder when you pull the trigger. It is much more handier using one of them for XLR and T/S connectors as oppose to the normal style soldering irons.

I dont really have a technique, but find with the general soldering iron, it is much easier to heat up your connection then place the solder onto the heated area, as oppose to holding your iron there and applying solder, Ive found that if you touch the solder to the gun your solder will often become messy, and your tip gets all crappy if your making a number of connections... I have a tutorial on soldering somewhere form work, Ill type it out and post it later tonight =)
pick up my long-nosed pliers and grab the solder cup with the pliers, to cool it before the heat can get to the heat-shrink tubing.” - DMXtools
Now that’s an interesting technique - Where were you yesterday when I had to re-expand some shrink tubing with them same but in this case 60° bent nose, micro needle nose pliers after it shrunk? What a pain in the rear. I have 4 pair of micro needle nose and a 7" pair of needle nose, is there any advantage to using the long nose needle nose for disapation or would the micro/electronics needle nose do? Must work well on the cursed thermoplastic wire well in any case. I get it. I’m going to try this method, what a idea! As opposed to me having heat shrink over the wires that I’m planning on letting shrink as it cools, you are transferring the heat into a heat sink that is the pliers. Good idea, I’ll have to try that especially in confined spaces like a 6 or 7 pin XLR. I was before grabbing the wires with the pliers before I learned to hold the cable better and not need them. So if I understand right you are not holding the wires you grab the pan/tray of the pins and it cools by transfer of heat the wire before it melts the insulation... New concept for me, grab the pan not the conductor - thanks!

Tinears3938, a Ratchet set to hold the plug, another good idea. I’m going to have to check it out so I can recommend it to our field tech people that don’t have a Pana Vise #PV201. Any idea on what size - assuming it’s not a deep throat. Is it six point or 12 point? I have the economy model of the vise not because of price but it’s jaws are small enough to work with without being the other short jaw non-PC board type in melting the rubber grips. On my vise, the plastic jaws are fairly well melted but not as much as a rubber jaw would be. Too bad either design of vise is not quick release as it should be. Going from Soco to XLR is a lot of turns on the vise. The Pana Vise I have is mounted on some 1/4" plate steel with a stand to hold the solder and weigh it down. I feed the solder thru the vise and it acts kind of like the thread on a sewing machine in preventing it from unraveling too fast and keeping the end of it near where it needs to be. Holding chop sticks is I’m sure for all of us good training in holding the wire, the solder and the gun/iron at once.

On the Weller gun very much like your’s above, I started with one especially for Socopex plugs but it’s a bit inaccurate for me especially for XLR stuff. The tips on the gun are a bit wide, bulky and thick for most work for what I do and I need an accurate temperature setting. I still infrequently have to do 60 some odd analog pin plugs and constantly have to do 37pin DMX data plugs and I would be hard pressed to get my own old 100/140 gun into such a thing much less any thing with more pins than 3. Kudos that you can get it all done with a soldering gun but have you tried a quality soldering iron and base station such as a $100.00 Weller #WES50? They seem as one particular model of gun to do a good job and you can vary the temperature between 350-850°F, than be fairly well assured it’s going to be at that temperature and stay that way. I bought two of them for the people assisting me and while the tip that is sold with it is a bit small for my tastes it’s still able to get to the proper temperature to solder a 12 ga wire. I was just using one of these solder stations the other day. My old soldering gun would never get hot enough to do more than cold solder pins - it would not get up to 850°F no matter what I did. Seemed big an powerful than I bought a solder station. What was I doing yesterday??? Oh’ yea, we buy the crimp male version of a 37pin Socopex plug for truss snake 8-Circuit DMX data cable because they break less frequently but use the solder style females for the other side because they are cheaper. I had to re-wire the female end of a data snake. Had only a half hour to get it done while the truck was being loaded - 37 pins ½ hour, I can do that in my sleep - almost given I’m still more electrician/carpenter-barbarian than electrician/electronics person.

For normal use and when I’m not at my assistant’s work table to get something done on the fast, I use a $260.00 Grainger Weller #EC1002, Soldering Iron & Base Station, with Ergonomic Pin & Stand. 60w, Calibrated Electronic Variable Temperature Control, Tip is Voltage & Field Protected, 350-850°F - as it’s discontinued description goes. It does everything from soldering 12 ga. Wire to Socopex pins to ribbon wire for me plus I can leave it on all day and 4 years later of constant use I’m yet to need to replace the tip. The WES50 solder stations are similar but the tips do wear out and are smaller - more refined for electronics work. I like a larger dia. tip myself.

Anyway for either solder station, I set my iron to somewhere between 650 and 700°F and it’s good for most purposes, or 850+ for Soco pins and I can leave that setting on all day including during lunch much less never turn it off and it will maintain the setting without damaging the tip or gun. If I’m working on really small wires than I do a lesser setting - around 400°F. I like being able to vary my temperature especially in matching up with the dia. of the solder size I’m using. I have some micro stuff for those times I’m doing the electronics stuff just as I have a third size larger than 0.5mm for XLR work. There are times when I want something like a 0.3mm and times I want something like a 1.2mm for soldering a grounding ring.

On removing solder, I tried the heating up the pins than slapping the solder out of them method, it’s not bad to learn but I’ll stick with a solder sucker myself. Our old man teaches that technique, it’s good to learn but I prefer a solder sucker. Takes some practice to do properly but after you learn a technique for what you are working on it’s faster and easier to use the tool. McMaster Carr #7752a13 works well, less effort and less chance of melting the plastic surrounding the pins too - much less you don’t have to play with grabbing hot things necessating that they are not clamped in a solid vise. They sell mini versions of the solder sucker and I highly recommend trying this method for extracting the solder after you learn the slamming technique.

So back to the reason for my reply, yep, “it’s the factory ones you need to fix.” More from the cable being stretched than from a bad or cold solder joint. Female connectors on all types of cable are also about 80% more prone to be the cause of the problem than the male end - notice that? Repaired five hoist cables at 16 ga / 7 conductor type SO this morning, and with the exception of two that were cable jacket cuts, the rest were broken wires on the female side and that’s the norm no matter what cable you use. Somewhat rare the male end of any wire will go bad. Which end is the one that’s tugged just a bit further or gets caught up in a chain hoist?

My question tinears3938 is if you are not using heat shrink, much less not noting that you tin the wires at least, what about the un-jacketed shield wire? It at very least, it will if not at least tinned cause endless problems because once the strain relief is tightened it’s going to shove the un jacketed shield into the other pins once the cable is moved about while in use. Plus there are the problems with the broken and short wires that when the cable is twisted that will touch other pins causing Gremlins in your system that are hard to detect unless they are held together with shrink tubing or at least kept out of the area by tinning the first 1/4" worth of wire away from the pan of the pins.

I used to just tin the shield wires without doing the heat shrink. It served fairly well for a time but tended to break down the shield at the end of the tinning with use. Now I automatically heat shrink it perhaps even apply a bit of adhesive to the heat shrink, than as a goal put a larger size of heat shrink over the main heat shrink so as to insulate the pan of the pin also. I do agree that as long as the insulation of the wire is not stripped beyond the tray or pan you solder the wires to on the pin that it’s fine for a repair, but what about thermoplastic insulated wires? It would seem that your smoking soldering gun in soldering wires to pins would have just as many problems with thermoplastic insulation failing while the solder is cooling as normal soldering would entail thus my use of heat shrink on those wires to make it shrink to the thermoplastic instead of further melting the thermoplastic insulation. Another thing about tinning the braided shield is that I found on cheap thermoplastic wire, frequently by the time I finished tinning the shield wire for 1/4" of it’s length the inner conductors got too hot and their insulation failed.

I’m not slamming your technique or tool use, instead I’m interested in more specifics about it’s use. Since you are not using heat shrink how do you treat the uninsulated Pin #1 shield wire? How do you deal with 60 or 90c thermoplastic wire that melts way back from where you stripped it as it cools and frequently will melt where the wires come together back at the outer jacket should you get the shield wire too hot? How do you deal with - assuming Neutrik plugs, the wires being pushed back into the pans due to the strain relief pushing them that direction once tightened?

At least I think I still have my old solder gun at the bottom of my road box, should your methods be of interest I might just pull it out of it and give it another try - sounds interesting. What temperature does it operate at in it’s dual setting? I have a constant stack of cable to repair even if my assistant does her best to stay on top of it. Than there are the emergency spares that are always out of stock to be building - again. Or the emergency repairs that always have to get noted as the show is loading out.

Anyway, interesting subject, hope both Tinears3939 and DMXtools can keep it up. I’m sure we all can learn from each other in it not to mention the silent people thinking what are they talking about. I have to replace the circuit board on my Clear Com because I overheated it what?!!! Soldering skills for all types of things are useful for all to learn about. Debating techniques is very much of use. One technique is not the most proper nor is it right for all purposes.

Brian Ship.
Guys no don't try to use a weller pistol gun on circit boards, 36 pin data cables or any thing you need precise soldering heat control on.
Back at our shop we have weller digital display station. We use the pistol grip for emergency field repairs only. To answer ya'lls other questions we use Swicthcraft , 3M & Amphenol connectors premium grade Belden wire not the cheap stuff from your local R.S. store same way with the solder Kester .031in dia. rosen core solder flows tins & melts at lower temps. than other brands, & yes ship we use suckers & desoldering wick as well. One main point is keep tour tips clean ,tight & tinned, replace them when they look burned as for the socket I think its a 9/16 12pt. 3/8 drive. I have been in this busness for over 30 years, soldering I can do laying on the floor reaching around beams using a mirror to see the joint. Try this solder with one hand! Mag light in teeth other hand holding inspection mirror. ( never lend your Mag light to anyone! ) God gave us 5 fingers per hand it only takes 2 to hold a iron, but which 2 ?? If your careful and pay close attention you won't burn the wire insulation back any more than a 1/16th in. As for pin #1 twist it tight befor soldering & rap a piece of 3M 33 elec tape around the bare sheild & yes tin the wire first just the tip not the whole stripped area or you will burn back the insulation. Oh yea, you only preheat the gun on high for a few seconds. This is a cool site I stumbled on it by accident, I love talking shop an if this helps the younger generation thats great !!!!!!!
Jeff aka your Daddy he he he!
Hi, I run a DJ and Lighting Company, which also offers a service department. There are a lot of good hints and tips on here, which I think can be reduced to a couple of basic principles:

1. Using a temp control iron is your best option and is a great investment. Gas irons are also handy for your toolbox for field jobs. I set my iron to 350 degrees C for every day use (Sorry - Metric in Australia!!).
2. Place a small amount of solder onto the tip of the iron before attempting to tin your wire or solder a connection. This improves the conductivity of the heat and helps prevent damage to the insulation (or component if doing board work).
3. ALWAYS tin your wire before soldering it to the pins. I strip the insulation back a little further than I want and then trip the end once I have tinned the wire. If you simply twist the wire and then solder it into (or onto) the pin it will unwind which will result in a dry joint.
4. Use a stable platform when soldering. If the job moves excessively, you will end up with poor joints. I use a hobby vice mounted onto a wooden base, but a block of wood drilled with a suitable diameter hole, or socket (as described in an earlier post) will work just as well.
5. Apply some solder directly to the pin prior to making the connection. For hollow pins, fill them with solder and keep the heat applied whilst you insert your tinned wire. For solid pins, the principle is the same, but obviously the solder is directed to one side of the pin.
6. As with anything - practice will help you, so grab those off cuts of wire and practice soldering them together.

I do not use heatshrink on my XLR connectors, as I do not feel that there is any risk of shorts with my connections. Also, heat shrink hinders your visual inspection of connections in faulty leads. However, heatshrink is often essential for 1/4" Jacks (I do know some non-metric sizes) and RCA plugs, where the plugs themselves are not that robust and there is close proximity between the connectors.
I hope that this is helpful.

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