Got any soldering hints/tricks for DB9 (serial) connectors?

[infopimp]

Hello. I am about to re-do the male side of a DB9 serial connection for a 4-servo wing harness.

I purchased a small soldering tip and have a very nice soldering iron... but what I don't have is experience. Do you have any tips for soldering this tricky, tight configuration you might share with a newbie?


For example: How do I "tin" the receptor end on the plugs? Where should I apply the heat when soldering? I can't fit a heatsink in there and am worried I will melt the plastic. (I'm probably just overthinking this???)

The item I am soldering is shown below ( photos borrowed from one of the really good build threads at http://www.F3X.com )

Thanks in advance.



-steve

[jeffs555]

Don't tin the plug, you need the cups to be free of solder and open. Just tin the wires, then insert into the pin. Make sure you are using flux core electronic solder. Then heat the outside of the pin, and touch the solder to the inside of the pin, not to the iron. When the solder melts and fills the cup, remove the heat and try to keep the wire from moving until the solder cools. Dont worry about melting the plastic. As long the iron is hot enough and you only keep it on the pin until the solder melts, it should be fine.

[Goinav8n]

Keep the tip of the iron clean. It will help with heating the socket. Dont worry about the plastic melting. It can actually take some abuse. Also since your using a DB9 connector make sure you have the positive wires and ground wires that are going to be grouped together soldered as tightly together as you can. The slot they fit in is very narrow. Dont forget the heat shink before you solder it on.

Just think it out before you start and things should go smoothly

Jeff

[MarkusN]

What also helps: Plug the female counterpart in. That helps to stabilise the pins so they don't go wandering in the hot insulator.

If you have it: use thin heatshrinking insulation tube over the individual wires. Have those long enough so you can push the tubing up high enough so it doesn't shrink while soldering. And don't forget to add the tube to the wire before soldering :D

[village_idiot]

Don't heat the pins too much or the plastic that hold them melts! Keep the copper on the wire short (not more than about 1/16 to 1/8 inch) and you shouldn't need to worry about heatshrink.

And I sometimes tin the pins too, depends on the size wire I am using. Small wire and I tin, 22 guage (or larger) and you really can't tin the pins. If you do not tin the pins, make sure to touch the wire/pin with solder when it gets hot or you may not get a good joint.

[infopimp]

See, this is why I post "dumb" questions here - you guys rock! That is killer advice, all of it. I would have no doubt been running back to the electronics store after biffing my first try.

I might try this: small heat shrink around each wire, then add a dob of "goop" (Shoe Goo) around the entire works. Reason being: my previous setup (used plane, someone else's soldering) had some wires come loose after repeated wear and tear... thinking that solidifying the 'mass' of wires might help. Another way to do this would be to have a large heat shrink tube around the whole works. Tried either of these?

[village_idiot]

Normally the clamp in the connector shell takes care of keeping things from moving. Did the connector have a shell on it? If not you will probably add more weight with hot glue than a plastic shell will weigh.

I have been soldering wires into various connectors for more than 20 years, I have yet to see the benefit of heatshrink. I do have some cables that are nearly 20 years old now that are still in good shape after all those years of hard use.

Also did you know that you can buy D connectors that use crimp on pins and sockets? That would save you from soldering, and might be more durable in certain situations.