Making connection to very fine wire?...

B

Bob Engelhardt

Guest
On 11/30/2021 11:19 AM, Liz Tuddenham wrote:
Bob Engelhardt <BobEngelhardt@comcast.net> wrote:

On 11/29/2021 5:34 AM, Liz Tuddenham wrote:
There is a further hazard which nobody has mentioned yet: if the wires
are very fine (48swg or higher) and they are made of copper, they will
dissolve in ordinary solder. The way to overcome this is to use a
solder that is already saturated with copper, such as \"Savbit\".

It rarely causes a problem with normal work, but becomes significant in
the repair of moving coil meters and similar fine work.

I didn\'t measure the strands, but 8 of them twisted together made a
0.01\" diameter conductor. Pretty fine. Time will tell, but with any
luck I\'ll be dead before it\'s a problem.

I really hope I have misunderstood your reply: the copper dissolves
during soldering, not afterwards; so unless you are doing something
remarkably careless, you should still be alive at the end of it.

:)

I\'m the one who misunderstood. For some reason, although you did not
even imply it, I took it to mean that the copper would dissolve over time.
 
L

Liz Tuddenham

Guest
Bob Engelhardt <BobEngelhardt@comcast.net> wrote:

On 11/30/2021 11:19 AM, Liz Tuddenham wrote:
Bob Engelhardt <BobEngelhardt@comcast.net> wrote:

On 11/29/2021 5:34 AM, Liz Tuddenham wrote:
There is a further hazard which nobody has mentioned yet: if the wires
are very fine (48swg or higher) and they are made of copper, they will
dissolve in ordinary solder. The way to overcome this is to use a
solder that is already saturated with copper, such as \"Savbit\".

It rarely causes a problem with normal work, but becomes significant in
the repair of moving coil meters and similar fine work.

I didn\'t measure the strands, but 8 of them twisted together made a
0.01\" diameter conductor. Pretty fine. Time will tell, but with any
luck I\'ll be dead before it\'s a problem.

I really hope I have misunderstood your reply: the copper dissolves
during soldering, not afterwards; so unless you are doing something
remarkably careless, you should still be alive at the end of it.

:)


I\'m the one who misunderstood. For some reason, although you did not
even imply it, I took it to mean that the copper would dissolve over time.

I didn\'t make it very clear; there might be a long-term effect too, but
I haven\'t heard about that.

If you use copper-loaded \'Savbit\' it will prevent any copper dissolving
and will also make the soldering iron bit last longer (which was its
original selling point). Silver also dissolves in solder, which is why
silver-loaded solder has to be used on the silver-plated ceramic
tagstrips of older Tektronix oscilloscopes.


--
~ Liz Tuddenham ~
(Remove the \".invalid\"s and add \".co.uk\" to reply)
www.poppyrecords.co.uk
 
L

legg

Guest
On Sun, 28 Nov 2021 21:45:51 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

Mike Coon <gravity@mjcoon.plus.com> wrote:

In article <MPG.3c0c338eb52d0d5e989b75@news.eternal-september.org>,
rmowery42@charter.net says...

In article <gQqoJ.126330$IW4.67570@fx48.iad>, BobEngelhardt@comcast.net
says...

Each filament is insulated with a varnish. How can I make a connection
to these conductors? Strip the varnish & solder, or can a crimp
connection be made through it? If strip, how to? Is it not copper &
not solder-able? Or is it not even practical to re-use this wire at
all? So many questions, but I hope that I can save a LOT of trial &
error if somebody has experience with this.

BTW - I want to use this for its size & flexibility, to attach an LED to
be fed into small spaces for illumination.




Depending on the varnish there are several ways to get it off not
counting the scrapeing . Some will burn the varnish off with the heat
of the soldering iron. On others I have taken a butane lighter and
burnt off the insulation then clean off the burnt part.

Decades ago I recall a varnish that was specificaally formulated to
become a flux when soldering. So I am sure it is possible, but whether
that is what you have got is a different matter!

It\'s very common nowadays, so the chances are that these wires will be
insulated with it.

Any links to this wire grade?

I\'ve seen solderable, but would be really surprised to see
self-fluxing.

Any soldering will produce brittleness, in fine gauge wires,
so crimping preferred - both with strain relief.

RL
 

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