Problems soldering 2.1 mm DC line socket

[Christopher Tidy]

Hi all,

I recently bought a 2.1 mm DC line socket from Maplin (part no. JK11M)
so I could power a project using a plug-in power adaptor (wall wart).
Soldering a lead to the outer coaxial contact was no problem, but when
I tried to solder a lead to the inner contact, the plastic insulation
melted!

I'm not a novice to soldering and I wasn't using an inappropriately
large iron. The iron I was using is an Antex rated at 18 watts,
although it isn't a regulated iron. I didn't touch the plastic
insulation with the iron. The joint clearly didn't get hot enough to
melt the solder, so I reckon the plastic must have melted at less than
180 deg. C.

The Maplin socket design is bad in two ways. Firstly the insulator is
made from a thermoplastic, and secondly the solder bucket for the inner
contact is right next to the plastic insulator.

So I have a few questions. Are all 2.1 mm line sockets like this or are
there better designs out there? If there are better ones available,
where can I get one from? And how are you supposed to solder these
sockets with thermoplastic insulators?

Suggestions would be appreciated.

Best wishes,

Chris Tidy

 

[Homer J Simpson]

I'm not a novice to soldering and I wasn't using an inappropriately
large iron. The iron I was using is an Antex rated at 18 watts,

That's the problem. You need a 60 W iron and you need to work FAST! Anything
you can do to make the solder stick faster will help.

 

[Arfa Daily]

That's the problem. You need a 60 W iron and you need to work FAST!
Anything you can do to make the solder stick faster will help.

The trick to soldering any of these small connectors - DC power, audio or
RF - is to fit a mating plug or socket to the item you are trying to solder.
Then, with it all held still in a small vise or helping hand, tin the
connections. Even if the centre insulation does soften, the pin / socket
will be held in place by the mating connector that you've fitted. After
tinning the contacts, tin the wire ends, then solder the wires to the
contacts as 'touch' joints. Although the conventional soldering wisdom is
that a good mechanical joint should be made, before applying solder, in the
case of small connectors, a touch joint is good enough, as the plug's strain
relief will normally supply enough mechanical stability to the joints.

Arfa

 

[Christopher Tidy]

I have a 40 W iron and a 75 W iron too. The 75 W is far too unwieldy,
so I'll try the 40 W next time.

The trick to soldering any of these small connectors - DC power, audio or
RF - is to fit a mating plug or socket to the item you are trying to solder.
Then, with it all held still in a small vise or helping hand, tin the
connections. Even if the centre insulation does soften, the pin / socket
will be held in place by the mating connector that you've fitted. After
tinning the contacts, tin the wire ends, then solder the wires to the
contacts as 'touch' joints. Although the conventional soldering wisdom is
that a good mechanical joint should be made, before applying solder, in the
case of small connectors, a touch joint is good enough, as the plug's strain
relief will normally supply enough mechanical stability to the joints.

I thought of this just a few minutes ago while I was looking at the
melted plug. Neat idea. I wish I had thought of it earlier!

By the way, does anyone know of any 2.1 mm line sockets made from heat
resistant plastic?

Thanks for the help.

Best wishes,

Chris

 

[Homer J Simpson]

By the way, does anyone know of any 2.1 mm line sockets made from heat
resistant plastic?

No reason they aren't made but if you can buy the original connectors,
someone somewhere is soldering them OK.

 

[3T39]

Hello, Christopher!
You wrote on 13 Nov 2006 09:32:48 -0800:

CT> I recently bought a 2.1 mm DC line socket from Maplin (part no. JK11M)
CT> so I could power a project using a plug-in power adaptor (wall wart).
CT> Soldering a lead to the outer coaxial contact was no problem, but when
CT> I tried to solder a lead to the inner contact, the plastic insulation
CT> melted!

CT> I'm not a novice to soldering and I wasn't using an inappropriately
CT> large iron. The iron I was using is an Antex rated at 18 watts,
CT> although it isn't a regulated iron. I didn't touch the plastic
CT> insulation with the iron. The joint clearly didn't get hot enough to
CT> melt the solder, so I reckon the plastic must have melted at less than
CT> 180 deg. C.

CT> The Maplin socket design is bad in two ways. Firstly the insulator is
CT> made from a thermoplastic, and secondly the solder bucket for the inner
CT> contact is right next to the plastic insulator.

CT> So I have a few questions. Are all 2.1 mm line sockets like this or are
CT> there better designs out there? If there are better ones available,
CT> where can I get one from? And how are you supposed to solder these
CT> sockets with thermoplastic insulators?

CT> Suggestions would be appreciated.

CT> Best wishes,

If you have space, use of a small crock clip positioned just a little
downstream of the intended soldering point, can act as a heat sink and carry
some of the heat away, give yourself just enough free metal to make a quick
joint.

With best regards, 3T39. E-mail: [email protected]

 

[Jim Land]

Hello, Christopher!
You wrote on 13 Nov 2006 09:32:48 -0800:

CT> I recently bought a 2.1 mm DC line socket from Maplin (part no.
JK11M) CT> so I could power a project using a plug-in power adaptor
(wall wart). CT> Soldering a lead to the outer coaxial contact was no
problem, but when CT> I tried to solder a lead to the inner contact,
the plastic insulation CT> melted!

CT> I'm not a novice to soldering and I wasn't using an
inappropriately CT> large iron. The iron I was using is an Antex
rated at 18 watts, CT> although it isn't a regulated iron. I didn't
touch the plastic CT> insulation with the iron. The joint clearly
didn't get hot enough to CT> melt the solder, so I reckon the plastic
must have melted at less than CT> 180 deg. C.

CT> The Maplin socket design is bad in two ways. Firstly the
insulator is CT> made from a thermoplastic, and secondly the solder
bucket for the inner CT> contact is right next to the plastic
insulator.

CT> So I have a few questions. Are all 2.1 mm line sockets like this
or are CT> there better designs out there? If there are better ones
available, CT> where can I get one from? And how are you supposed to
solder these CT> sockets with thermoplastic insulators?

CT> Suggestions would be appreciated.

CT> Best wishes,

If you have space, use of a small crock clip positioned just a little
downstream of the intended soldering point, can act as a heat sink and
carry some of the heat away, give yourself just enough free metal to
make a quick joint.

Yes, a heat sink is a good idea, but as Christopher originally stated,
the point he is trying to solder is right next to the plastic that melts,
so there's no room for a clip.

The idea of inserting the mating connector probably provides a little
heat sink. If you want a larger one, try suspending the connector
(solder connection up) in a cup of water, so the water covers the
plastic, but the solder connection is out of the water. That should keep
the plastic cool while you solder. Just dry out the connector before you
use it.

 

[Christopher Tidy]

I bought two more sockets from a different supplier and tried again.
This time I used a 40 W soldering iron and a mating plug as a heatsink.
The results were acceptable, but only just. These sockets also use
thermoplastic insulators, and both suffered a little damage. Because
the solder bucket is right next to the insulator, it seems that the
insulator will inevitably be softened, and that the mating plug is
essential to hold the central pin in place. For anyone trying to solve
the same problem in future, the mating plug is the key.

It's a pretty pitiful piece of design really. An extra 5 mm between the
solder bucket and insulator or a change to a heat resistant plastic
would make all the difference.

Thanks for the help.

Best wishes,

Chris

 

[Baron]

I bought two more sockets from a different supplier and tried again.
This time I used a 40 W soldering iron and a mating plug as a
heatsink. The results were acceptable, but only just. These sockets
also use thermoplastic insulators, and both suffered a little damage.
Because the solder bucket is right next to the insulator, it seems
that the insulator will inevitably be softened, and that the mating
plug is essential to hold the central pin in place. For anyone trying
to solve the same problem in future, the mating plug is the key.

It's a pretty pitiful piece of design really. An extra 5 mm between
the solder bucket and insulator or a change to a heat resistant
plastic would make all the difference.

Thanks for the help.

Best wishes,

Chris

Turned, solid brass pins, used as a plug will help ! Mine are 2" long
and provide a good heatsink for the centre pin ! It also helps that
you can clamp the brass pin into a vice to hold the assembly steady.

But I do agree, a better plastic would help. I also get this softening
on SO239 connectors that do not use teflon or similar, as the
insulator.

 

[quietguy]

I have recently made up 6 leads using these connectors and have not run
into any problems - a hot iron, tin the tags and the wire first, and add
just enough heat to sweat the wire to the tags. If I was worried about
too much heat I would just hit the joints with some cotton wool dipped in
metho to get a rapid cooldown

My connectors come from DSE/Tandy - nothing special

David