solder pot?

W

Walter Harley

Guest
I have thousands of 24-ga stranded wires that need to be cut to particular
lengths, stripped, and tinned at the ends. (They connect various
front-panel controls and jacks to a circuit board, in an audio-frequency
low-power device I sell.) I've been doing it by hand with strippers and a
soldering iron, but it takes way too long.

How is this done efficiently in the manufacturing world? Is the tinning
what a "solder pot" is for, and if so, how are they used?
 
Walter Harley wrote:
I have thousands of 24-ga stranded wires that need to be cut to particular
lengths, stripped, and tinned at the ends. (They connect various
front-panel controls and jacks to a circuit board, in an audio-frequency
low-power device I sell.) I've been doing it by hand with strippers and a
soldering iron, but it takes way too long.

How is this done efficiently in the manufacturing world? Is the tinning
what a "solder pot" is for, and if so, how are they used?
Click to expand...
First, there are automatic strippers that look and seem to operate
like a pencil sharpener.
And yes, there are solder pots for tinning like you suggest, from
small ones (1/2 lb solder i would guess) to larger than you need.
Check DigiKey or Mouser..
 
In the aerospace world I was taught how to tin with a solder pot as
well as with a soldering iron. On the job I never used a pot, but then
I didn't do much soldering. For occasionally tinning a few wires it
was less trouble to just use an iron. The folks who worked in
Production may well have used solder pots, though.

The tinning technique with a solder pot was to apply a drop of liquid
flux (rosin) to the stripped wire, then dip almost all the stripped
portion into the pot. You left a small length, equal to one or two
diameters of insulated wire, above the surface. The tinning happened
very fast, practically instantaneously. There was no need to wait,
stir the wire around, etc.

We always stripped and tinned a generous length of conductor, more
then needed, then cut off the excess after wrapping the tinned wire
around the terminal in preparation for soldering.

It wasn't necessary to tin while the flux was still wet. You could
prepare a batch of wires by stripping and fluxing, then do the tinning
later.

Just before dipping, we had to skim off the oxide (I think it's called
"dross") floating on top. The pot was kept full, so all you had to do
was push the dross onto the flat area surrounding the well of molten
solder. This was done with a little metal spatula. The ones in our
classes were just strips of sheet aluminum, apparently scrounged from
the sheet metal classroom.

Although I only did one at a time in training, it would be practical
to tin several wires at once in the pot.

As far as how long it takes a solder pot to get ready from a cold
start, I have no idea. During class it was always molten as far as I
ever saw.

--

Paul Hirose <ewwb4-khh25@earINVALIDthlink.net>
To reply by email delete INVALID from address.
 
"Walter Harley" <walterh@cafewalterNOSPAM.com> wrote in message
news:c3afk2$uiv$0@216.39.172.65...
I have thousands of 24-ga stranded wires that need to be cut to particular
lengths, stripped, and tinned at the ends. (They connect various
front-panel controls and jacks to a circuit board, in an audio-frequency
low-power device I sell.) I've been doing it by hand with strippers and a
soldering iron, but it takes way too long.

How is this done efficiently in the manufacturing world? Is the tinning
what a "solder pot" is for, and if so, how are they used?
Click to expand...
For big-time production, you would use a machine to measure, cut & strip
your wires; one pass through the machine from wire spool to ready-to-use
pieces. However, these machines are expensive, and, since you are now doing
this operation by hand, your product volume may not be high enough to
support full automation. You might want to go to a semi-automatic wire
cutter, then use a semi-automatic wire stripper. Depending on your
insulation, a thermal or mechanical blade stripper might be best. See
http://www.eubanks.com for a start.

As for tinning, you really should wrap a stranded wire onto its termination,
and then solder it.

BTW, why use stranded wire? Solid is cheaper & easier to work with. Do you
really need the stranded wire?

Ed
 
"Ed Price" <edprice@cox.net> wrote in message
news:_CU6c.19499$uh.13538@fed1read02...
As for tinning, you really should wrap a stranded wire onto its
termination,
and then solder it.
Click to expand...
In general one end of the wire goes to a pad on a PCB, and the other gets
connected to a jack or potentiometer. At the PCB end, if I don't tin, it's
too hard to reliably get all the strands into the hole. Too much risk of an
inadvertent short-circuit.


BTW, why use stranded wire? Solid is cheaper & easier to work with. Do you
really need the stranded wire?
Click to expand...
Fair question. Probably a bit of chicken and egg going on. I always felt
like, for hand stripping, with solid wire there's too much risk of nicking
the wire and having it eventually break, either during assembly or during
some mechanical shock afterward. And these wires do end up going into some
tight spaces, so they get a bit of mechanical strain during assembly.

But if I used a hot-wire stripper, then there would be no risk of nicking
the wire, so reliability would be less of a problem. Maybe that's a good
direction for me to go; it would certainly be easier, and as you say,
cheaper.

Are there other issues with stranded versus solid wire? The enclosure is
solid, contains no moving parts, and is not opened except in the unlikely
event of service; so the wires do not normally have to flex.
 
"Walter Harley" <walterh@cafewalterNOSPAM.com> wrote in message
news:c3hu7s$set$0@216.39.172.65...
"Ed Price" <edprice@cox.net> wrote in message
news:_CU6c.19499$uh.13538@fed1read02...
As for tinning, you really should wrap a stranded wire onto its
termination,
and then solder it.

In general one end of the wire goes to a pad on a PCB, and the other gets
connected to a jack or potentiometer. At the PCB end, if I don't tin,
it's
too hard to reliably get all the strands into the hole. Too much risk of
an
inadvertent short-circuit.


BTW, why use stranded wire? Solid is cheaper & easier to work with. Do
you
really need the stranded wire?

Fair question. Probably a bit of chicken and egg going on. I always felt
like, for hand stripping, with solid wire there's too much risk of nicking
the wire and having it eventually break, either during assembly or during
some mechanical shock afterward. And these wires do end up going into
some
tight spaces, so they get a bit of mechanical strain during assembly.

But if I used a hot-wire stripper, then there would be no risk of nicking
the wire, so reliability would be less of a problem. Maybe that's a good
direction for me to go; it would certainly be easier, and as you say,
cheaper.

Are there other issues with stranded versus solid wire? The enclosure is
solid, contains no moving parts, and is not opened except in the unlikely
event of service; so the wires do not normally have to flex.
Click to expand...
If you do stay with stranded, you might find one feature of the fancy wire
strippers to be of help. Some strippers will cut and pull the sleeve of
insulation down to near, but not all the way off, the wire. This allows
handling the wire without the strands separating, but you have to flick off
the insulation sleeve just before you use the wire.

Ed
 
Walter Harley wrote:

I have thousands of 24-ga stranded wires that need to be cut to particular
lengths, stripped, and tinned at the ends. ... I've been doing it by hand
with strippers and a soldering iron, but it takes way too long.
How is this done efficiently in the manufacturing world? Is the tinning
what a "solder pot" is for, and if so, how are they used?
Click to expand...
Wire can be automatically cut to length, stripped, and tinned by a wire
processing machine. The machine costs around $50K or more.

A cheaper machine ($10-20K) cuts to length and strips the wire, which is
then tinned by hand in a solder pot. The wire can be semi-stripped
(insulation cut but not completely removed, to keep the strands from
fraying out.) To tin the wires, pull off the semi-stripped insulation,
twisting the strands slightly, dip the wire end into a small dish of liquid
flux, and dip briefly into the molten solder in the pot. Several wires can
be done at once--hold them so they don't touch each other or they will
stick together. The dross that forms on the surface of the solder pot needs
to be skimmed off periodically. The company that I used to work for had
special solder pot tables with steel tops. There was a hole in the top in
which the solder pot sat so that it was even with the table top. Kitchen
range hoods were used to exhaust the flux fumes.

It's also possible to cut the wire to length by hand, then strip it with a
benchtop pneumatic or electric powered stripper ($3K), then tin in the
solder pot.

Cut and strip machines are made by Schleuniger
<http://www.schleuniger.com/>, Komax, Kodera, and others. American Beauty
is one maker of solder pots.

You may be better off to farm the job out to a company that has the
specialized equipment to do the job efficiently, such as Squires
<http://www.squires.com/>.



--
--
Steve
 
"Steve Dunbar" <stvdnb@yahoo.com.INVALID> wrote in message
news:1064mmk7r6eq67d@corp.supernews.com...
Wire can be automatically cut to length, stripped, and tinned by a wire
processing machine. [range of options snipped...]
Click to expand...
Thanks, Steve, that's very helpful information!
 
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