OT- Best technique for soldering D Sub terminals ?

Like these- Solder Cup D-Sub Connector, DB15 Female - SD15S

I've used these many times before but it's been a while and now can't remember how I did it ! Maybe I tinned the wire ends with solder first but seems like the easiest would be to use liquid solder (real solder, not glue....should be kept refrigerated). Thoughts ?

I like to do it by first tinning each solder cup, then tinning the wire ends, then re-heating each cup/wire in turn and slipping the wire in when the solder melts.

Definitely hold the connector in a vise of some sort, and it is also nice if you can rig up a second vise or other arrangement for holding the cable in position.

You can hold each wire with a small needle-nose plier as you slip it into the solder cup.

Very thin solder is nice, as is a small tip on the iron.

I use a fly tie ing vise with magnifier. If i can hold both the connector and the cable in clips, I don't bother tinning.

this is a pretty good lesson

YouTube


and a little heat shrink tubing makes it look nice

When I did it for a living, tin connector cups, tin wire end, connector in a little vise, reheat the solder cup, dip the wire in, wait one second, remove heat, wait 4 seconds release, repeat

Pretinning the connector helps keep you sane so that you always get 1, 2, 3, 7 instead of some random pin

heat shrink makes it pretty if loose in a cabinet, but if in a housing not required.

awander said:

I like to do it by first tinning each solder cup, then tinning the wire ends, then re-heating each cup/wire in turn and slipping the wire in when the solder melts.
Definitely hold the connector in a vise of some sort, and it is also nice if you can rig up a second vise or other arrangement for holding the cable in position.
You can hold each wire with a small needle-nose plier as you slip it into the solder cup.
Very thin solder is nice, as is a small tip on the iron.

Click to expand...

This has always worked best for me, I did a few DB9s this way just last week.

1) binocular microscope or your own favorite brand of magnification.

2) strip the wire ends a bit long.

3) tin wire ends. The insulation will shink back a bit.

4) cut the tinned end short to the correct length, slightly longer than the open area of the solder cup.

5) tin the solder cup.

6) apply a drop of rosin flux (liquid rosin, diluted with ethanol) to the solder in the cup.

7) with the connector solidly fixed in a panavise, sweat each joint in turn by
heating the solder cup with the iron until the solder flows, the wire gets its
heat from the molten solder in the cup, melts, and submerges in the
solder cup.

8) deflux with ethanol and inspect.

Is leaded solder still the best choice? I don't think I've heard of a non-Pb that's better, what's the favorite out there?

I have done a lot of DB9, DB15, and DB25 connectors on cash registers and other systems and have never tinned the wire or the cup. Used a fairly large iron too because a large hot mass on the iron brings the cup and wire to temperature way before the heat can melt the wire insulation or the connector body. More damage to electronics is done with an iron too small than one too big in my book. The cash register set up guy was shocked I was working on the last one rather the first, and no crossed or failed wires anywhere.

jim rozen said:

1) binocular microscope or your own favorite brand of magnification.

2) strip the wire ends a bit long.

3) tin wire ends. The insulation will shink back a bit.

4) cut the tinned end short to the correct length, slightly longer than the open area of the solder cup.

5) tin the solder cup.

6) apply a drop of rosin flux (liquid rosin, diluted with ethanol) to the solder in the cup.

7) with the connector solidly fixed in a panavise, sweat each joint in turn by
heating the solder cup with the iron until the solder flows, the wire gets its
heat from the molten solder in the cup, melts, and submerges in the
solder cup.

8) deflux with ethanol and inspect.

Click to expand...

This method!

63/37


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The flux on tinned cup is good, to prevent really ugly and potentially qustionable joints, but I admit to not always doing that.

"Tinning", btw as far as the solder cup is concerned, means getting a decent amount of solder in it, not just a "coating". An average amount might be about 1/2 to 2/3 full, so that when the wire goes in, the solder comes up to the top and maybe bulges a bit. Do one or two an you will get the amount, because it varies with wire size.

garyhlucas said:

I have done a lot of DB9, DB15, and DB25 connectors on cash registers and other systems and have never tinned the wire or the cup. Used a fairly large iron too because a large hot mass on the iron brings the cup and wire to temperature way before the heat can melt the wire insulation or the connector body. More damage to electronics is done with an iron too small than one too big in my book. The cash register set up guy was shocked I was working on the last one rather the first, and no crossed or failed wires anywhere.

Click to expand...

So you held the wire with one hand, feed solder with another and keep soldering iron in your mouth?

I usually go for the pretinning method because its easier/faster.

MattiJ said:

So you held the wire with one hand, feed solder with another and keep soldering iron in your mouth?

I usually go for the pretinning method because its easier/faster.

Click to expand...

Actually, you hold the wire in left hand using small finger, hold tin wire with thumb, hold soldering iron with right hand and fix the connector with right hand small finger.

I usually do it like that. Use heatshrink only with long loose wires, not if you have cable with short stripping, the heat from soldering will ruin the heatshrink.

No pretinning needed, use 0.8mm flux core solder, if possible use lead solder with silver, this is a bit more expensive but for occasional soldering its very easy to use.

Do not use acid solder fluxes, actually you dont need any additional flux.

Also, if possible, use pre tinned wire. Most cables actually are pretinned.

Madis Reivik said:

I usually do it like that. Use heatshrink only with long loose wires, not if you have cable with short stripping, the heat from soldering will ruin the heatshrink.

Click to expand...

Kynar heatshink sleeve saves a day if you have to work with those crazy round multipole connectors. D-sub is easy to solder but some of those crazy Lemo/Fischer connectors with 50 pins stacked to 1" diameter round connector are total pain in the arse. Typically strain relief is so close that you can cut the cable sheath away only for really short distance and then you end up trying to juggle 50pcs half inch long conductors to correct pins

Kynar needs considerably higher temperature than ordinary heat shrink so it doesn't shrink prematurely nearly as badly as ordinary version.

"Oops, I think two of the pins in center are crossed":

When I tin, I dip the wire in flux, then dip it in a molten solder pot, which properly tins the wire and you dont need to use a soldering iron until you are ready to put it in the terminal. When you are done soldering, make sure you use an acid brush and alcohol to clean up the flux residue, it is corrosive. Being corrosive is how it cleans. Then you can heat shrink the wire if you need it. Tim


Oh and FYI, a properly crimped connection is more flexible than a soldered connection. Wires that are required to move have more of a chance of breaking near the solder joint because the joint can be too rigid.

Lots of good info on soldering the wires into these little hard to reach plugs / sockets. I've struggled with them for years. I finally bought the kind where you crimp ( or solder) the wires to the pins and then slip them into the case. You'll never go back to the solder together kind again! And the crimper is cheap enough to make it worth while even if you're only going to use it once. (you'll use it again!)

I have done thousands of D-sub-miniature connectors. I avoid soldering whenever possible. Most uses will tolerate a ribbon cable and IDC style connectors. Soldering even a DE-9 connector will take fifteen minutes to a half hour while you can terminate ribbon cable with a IDC style connector in less than a minute and the only tools you need are a wire cutter and a bench vise. And they are extremely reliable.

D-Sub Connectors | Connectors, Interconnects | DigiKey

In applications where individual wires must be used, I like to use crimp style connectors on individual pins that are inserted in a connector shell. This is far easier and more reliable than soldering if you use the proper, professional crimping tool (Look for brands like Amp, Molex, Greenlee, etc.) Ratchet styles are best, but plain ones are OK if they are FULLY CLOSED for each crimp: they will have a pair of flats that must touch to complete the crimp. No touch = no good.

If you must solder:

00. Fill your coffee cup.
0. USE A MAGNIFIER.
1. Strip wire.
2. Dip stripped end in rosin flux.
3. Tin it and trim to proper length.
4. Hold connector in a vise or other device.
5. Dip trimmed wire in flux again. This provides a small amount of flux for inside the connector's cup.
6. Insert tinned wire in connector's cup.
7. Using a temperature controlled iron with a 1/16 or 1/32 inch tip, heat the cup from below or the side (a SMALL bit of solder on the iron's tip helps a lot here to transfer the heat quickly).
8. After a few seconds of heating, touch the cup and wire with a small gauge, rosin core solder. Only a small amount is needed and it should quickly wick into the cup, around the wire. A small gauge solder will help to prevent solder bridges between pins.
9. Remove solder and iron and hold the wire dead still for about 10 seconds for the solder to harden. This is absolutely essential to prevent a cold solder joint.
10. Visually inspect the joint. The solder should have fully whetted to both the wire and the solder cup. And the surface should be bright, not dull.
11. Repeat for the other terminals.

A temperature controlled iron that is NOT set to the maximum is the best way to get a good solder joint. Too high of a temperature will encourage corrosion while you heat the joint and that can prevent proper whetting with the solder. Use a temperature that is proper for the solder alloy you are using. Again, a small amount of solder on the iron's tip is far better for ensuring rapid heat transfer than setting the iron to a higher temperature.

One more tip: All connectors are not created equal. Get name brand ones no matter what method you choose: you will not regret it.

D, do you still have that Vision Mantis? Seems like the perfect scope for this. Maybe about the only thing it'd excel at.

Nowadays I plug them into the opposite gender while soldering. I've have bad experiences with some of them softening with the heat of the iron and the pins moving in the thermo-plastic.

Probably because loads of them are now cut price Chinese ones !

andrewmawson said:

Nowadays I plug them into the opposite gender while soldering. I've have bad experiences with some of them softening with the heat of the iron and the pins moving in the thermo-plastic.

Probably because loads of them are now cut price Chinese ones !

Click to expand...

Havent had that problem even with cheap D-sub connectors but some other connectors melt easily. Circular DIN and mini Din for example.