On 10/28/23 3:32 PM, David Higton wrote:
> In message <BuudnQ1ot_sf96H4nZ2dnZfqn_GdnZ2d@earthlink.com>
> "56d.1152" <56d.1152@ztq9.net> wrote:
>
>> On 10/27/23 12:32 AM, The Natural Philosopher wrote:
>>> On 27/10/2023 04:44, 56d.1152 wrote:
>>>
>>>>
>>>>    Solder IS the best.
>>>>
>>> No, actually it often isn't...
>>>
>>> The problem with solder on *stranded* wire is that it wicks up the wire
>>> and reduces it's flexibility by binding the strands together: That
>>> creates a stress concentration where it stops and a likely cause of
>>> fracture failure under vibration. That is why crimps are the choice for
>>> cheaper connections in high stress environments (e.g. automotive) or if
>>> you must solder you absolutely need to mechanically support the wire
>>> upstream of the solder joint.
>>
>> I've had very bad luck with 'crimps' - esp when they are
>> exposed to the weather, but even in higher-vibration
>> environments. Wasted lots of time trying to track down
>> problems related to crimps.
>
> I still remember a very interesting one in the 1980s with a joystick
> for a Sinclair Spectrum.

DID have one ! :-)

> The box proudly proclaimed the use of gold
> plating in the internal connections. They used fully (i.e. not
> selectively) gold plated crimps onto stranded tinned copper wire.
> One of the joints, although completely mechanically sound, was not
> conducting electricity. Yes, that really was the interface between
> the crimp and the wire.
>
> I ran solder in and it was fine.

Yep ... crimps SOUND great - until you hit
the Real World.

Crimps are a cheap quick fix.

> There is a known, but unfortunately not widely known, problem in the
> interface between gold and tin.
>
> The lesson boils down to:
>
> 1) Never mix gold plated and tin plated connectors.
>
> 2) If you're using gold plated connectors, use selectively gold plated
> crimps in them.

Material compatibility IS always important.

Gold MOSTLY works with everything but, by
experience, not ALWAYS

Soldering IS a bigger pain in the ass, no question.
But it's MUCH more sure. It'll last 20-50 YEARS under
really crappy conditions.

My old old HOUSE is mostly SOLDERED electrical
connections - not even sure how they DID that
conveniently back in the day. However I'm NOT
worried about any of those connections - mostly
in the attic/ceiling - overheating like modern
screw-terminal connections that oxidize or
where the copper compresses and becomes loose.

A couple extra hours in 1950 meant 100+
years of reliability. When (likely soon) the
house is destructed the ELECTRIC will still
be 100%

Anyway ... BAD experiences with 'crimps' under
a variety of conditions. Soldered is much more
sure. Solder, add heat-shrink to spread out
the mechanical stress and weatherproof ...
electronic nirvana ! :-)

Sorry, I'm very old-school in this respect.
I really design for 100 years safe service.

On 10/27/23 2:42 AM, Ahem A Rivet's Shot wrote:
> On Thu, 26 Oct 2023 23:44:48 -0400
> "56d.1152" <56d.1152@ztq9.net> wrote:
>
>> But, remember "wire wrap" ? Still have the tools
>> for doing that. The more-extensive wrapping CAN
>> be as reliable as soldered connections.
>
> A good wire wrap connection (done with a power tool - we always
> used Gardner-Denver) is gas tight and extremely reliable as well as being
> faster and easier to modify than soldering.

Yep. Some of those "old world" solutions can
STILL be good solutions !

And, when everything's 100%, you can always
solder the wire-wrap.

As said somewhere, one employer had a *kit* LSI-11
box. It had BASIC, but everything of use was writ
in FORTRAN. They'd worked out all the wiring issues
and soldered the wire-wrap. From there on it was
just a software box. It's STILL around in a
storage spot somewhere, I'll bet on it. And it'll
still WORK - (assuming the 8" floppies can still
be read). Oh, dual 8" Shugart floppy unit ...
weighed about 75 POUNDS, BIG transformer :-)

On Mon, 30 Oct 2023 00:51:14 -0400, 56d.1152 wrote:

>> The other gang that understand interactions between electronics and
>> vibration are model flyers: radio control models, drones and, the most
>> vibration of all, IC powered free flight competition models: a current
>> F1C class model has a 2.5cc engine putting out around 1.3 HP at 30,000
>> rpm and carrying electronic flight timers and a GPS-based radio beacon
>> as a retrieval aid. Free flight models regularly travel 2km or so in
>> the course of a 3 minute flight, especially if the contest is being run
>> on Sculthorpe, an ex-RAF/USAF base in Norfolk,UK. This area is known
>> for its fresh sea breezes.
>
> An actual hydrocarbon-fuel engine WILL create a lot of very buzzy
> vibration - which WILL take its toll on every connection. It's
> amazing how quickly some connections will fail - chips can even work
> their way out of conventional sockets.
>
> And then, if an ignition system is involved, transient electrical
> noise ! :-)
>
High performance model engines have no ignition: they're either diesels
(COMPRESSION IGNITION burning an oil/kerosene/ether mix) or gloplug
ignition (battery heated plug with platinum coil to start, when running
combustion keeps the plug hot and burning methanol/oil mix, sometimes with
added nitromethane for more power.

You quickly learn how to protect in-model electronics and associated
wiring from the engine's vibration - if you don't you'll have lots of more
or less spectacular crashes. An F1C class model can climb vertically to
around 120m with a 3 second engine run.

--

Martin | martin at
Gregorie | gregorie dot org

On 10/30/23 9:05 AM, Martin Gregorie wrote:
> On Mon, 30 Oct 2023 00:51:14 -0400, 56d.1152 wrote:
>
>>> The other gang that understand interactions between electronics and
>>> vibration are model flyers: radio control models, drones and, the most
>>> vibration of all, IC powered free flight competition models: a current
>>> F1C class model has a 2.5cc engine putting out around 1.3 HP at 30,000
>>> rpm and carrying electronic flight timers and a GPS-based radio beacon
>>> as a retrieval aid. Free flight models regularly travel 2km or so in
>>> the course of a 3 minute flight, especially if the contest is being run
>>> on Sculthorpe, an ex-RAF/USAF base in Norfolk,UK. This area is known
>>> for its fresh sea breezes.
>>
>> An actual hydrocarbon-fuel engine WILL create a lot of very buzzy
>> vibration - which WILL take its toll on every connection. It's
>> amazing how quickly some connections will fail - chips can even work
>> their way out of conventional sockets.
>>
>> And then, if an ignition system is involved, transient electrical
>> noise ! :-)
>>
> High performance model engines have no ignition: they're either diesels
> (COMPRESSION IGNITION burning an oil/kerosene/ether mix) or gloplug
> ignition (battery heated plug with platinum coil to start, when running
> combustion keeps the plug hot and burning methanol/oil mix, sometimes with
> added nitromethane for more power.

Yea - but those are MODELS. Compression/glow + fuel still
means a lot of vibration. It's just not so important. Now
in actual 18-wheelers, 737s, M1 tanks - it IS very important.

> You quickly learn how to protect in-model electronics and associated
> wiring from the engine's vibration - if you don't you'll have lots of more
> or less spectacular crashes. An F1C class model can climb vertically to
> around 120m with a 3 second engine run.

Soldered is THE standard. Kinda mush the strands together and
solder and make sure you have some heat-shrink about 2X the
width of the exposed copper for stress relief. If the env is
"buzzy" then you have to strap down the wiring too.

I live in an old house. All the wiring was initially SOLDERED.
Not sure HOW they used to do that efficiently. The connections
where then either put in early twist cons and/or covered with
the olde-tyme rubbery "friction tape" (which they STILL sell).
The big wires are all industrial-qual early ROMEX with the
fiberglas shield inside and mostly in metal conduit.

It's a house with a lot of WOOD - no drywall crap. I am NOT
worried about what's in the attic or walls because the cons
are SOLDERED. They'll be good for 200 years. No oxidation,
no loosening probs associated with 'compression' connectors.

Anyway, as they say, you get what you pay for. Modern cons
are "adequate" - but not for 25 or 50, much less 200, years.
The wiring WILL oxidize or loosen - then get HOT. For
real-world equipment soldered IS still best as well for
reliability.

Recently replaced a plug socket. Put SOLDER over the
ends of the wires and used the SCREW DOWN terminals
rather than the "push in" ones. A little extra effort
PAYS OFF longer term.

Just sayin' ... there's "to code" and then there's GOOD.

On 05/11/2023 04:33, 56d.1152 wrote:
> Recently replaced a plug socket. Put SOLDER over the
>   ends of the wires and used the SCREW DOWN terminals
>   rather than the "push in" ones. A little extra effort
>   PAYS OFF longer term.

But best practice documents say using soldered/tinned wire in screw
connectors is bad due to differing expansion rates of the brass fitting
and solder. With enough sufficient thermal cycles the connection loosens
causing bad connections.

Obviously the experts should have consulted with you.

On 11/5/23 5:09 AM, mm0fmf wrote:
> On 05/11/2023 04:33, 56d.1152 wrote:
>> Recently replaced a plug socket. Put SOLDER over the
>>    ends of the wires and used the SCREW DOWN terminals
>>    rather than the "push in" ones. A little extra effort
>>    PAYS OFF longer term.
>
> But best practice documents say using soldered/tinned wire in screw
> connectors is bad due to differing expansion rates of the brass fitting
> and solder. With enough sufficient thermal cycles the connection loosens
> causing bad connections.

Don't expect any problems with a microns-thin
solder coating. The main goal there is to shield
the copper from oxidation/corrosion. My environ
IS a bit corrosive. House fires due to older
connections is NOT unheard of. Breakers protect
from overload, but cannot detect a degrading
connection.

Now if you just glob LOTS of solder on there ...

There ARE some kinds of 'goop' that claim to
protect the copper, but I'll stick with what
I know is good. Some of that goop is hydrocarbon
based - basically gasoline if it gets hot. The
silicone-based ... I'd have to see some good
studies as to HOW much that restricts current flow
and whether it can degrade PVC insulation long-term.

> Obviously the experts should have consulted with you.

They should have. I have lots of real-world experience
with marine applications.

56d.1152 <56d.1152@ztq9.net> wrote:
> Recently replaced a plug socket. Put SOLDER over the
> ends of the wires and used the SCREW DOWN terminals
> rather than the "push in" ones. A little extra effort
> PAYS OFF longer term.

Sounds like a recipe for a fire. I've seen screw terminals on 3D-printer
motherboards that were scorched after tinned wires had been put in them, and
they only carried maybe 100-200W at 12-24V.

The proper way to connect stranded wire in a screw terminal is to crimp the
wire in a ferrule or a fork or ring terminal (depending on the screw
terminal type) and then attach it to the terminal. If your crimping tool
isn't working reliably, either you're using it wrong or it's a crappy tool
that should be replaced. (The slip-joint pliers in your tool bag aren't a
proper crimping tool. Long-nose pliers aren't, either.)

Solid copper wire can be safely attached directly to screw terminals.

--
_/_
/ v \ Scott Alfter (remove the obvious to send mail)
(IIGS( https://alfter.us/ Top-posting!
\_^_/ >What's the most annoying thing on Usenet?

In message <UQ92N.38940$sqIa.2684@fx07.iad>
scott@alfter.diespammersdie.us wrote:

>56d.1152 <56d.1152@ztq9.net> wrote:
>> Recently replaced a plug socket. Put SOLDER over the
>> ends of the wires and used the SCREW DOWN terminals
>> rather than the "push in" ones. A little extra effort
>> PAYS OFF longer term.
>
> Sounds like a recipe for a fire. I've seen screw terminals on 3D-printer
> motherboards that were scorched after tinned wires had been put in them,
> and they only carried maybe 100-200W at 12-24V.

Never ever use screw terminals onto stranded wire that you've tinned.
Solder suffers from creep, so the pressure slowly relaxes until the
joint is loose. As stated above, a recipe for a fire.

David

On 11/6/23 4:56 PM, David Higton wrote:
> In message <UQ92N.38940$sqIa.2684@fx07.iad>
> scott@alfter.diespammersdie.us wrote:
>
>> 56d.1152 <56d.1152@ztq9.net> wrote:
>>> Recently replaced a plug socket. Put SOLDER over the
>>> ends of the wires and used the SCREW DOWN terminals
>>> rather than the "push in" ones. A little extra effort
>>> PAYS OFF longer term.
>>
>> Sounds like a recipe for a fire. I've seen screw terminals on 3D-printer
>> motherboards that were scorched after tinned wires had been put in them,
>> and they only carried maybe 100-200W at 12-24V.
>
> Never ever use screw terminals onto stranded wire that you've tinned.
> Solder suffers from creep, so the pressure slowly relaxes until the
> joint is loose. As stated above, a recipe for a fire.

True !

But be aware that electrical-quality copper ALSO 'creeps'.

Had a mystery power prob at my home a few years ago - it
turned out to be that the old screw-down connections in
the MAIN BREAKER had 'crept', loosened, over the years.
The electrician I'd hired put on rubber gloves and
re-tightened everything HOT. Good for another 20 years
I suppose.

For awhile I was responsible for control panels in
20-50 horsepower industrial devices. Once most were
10+ years old I decided to test the old power
connections. They were ALL getting loose - the copper
had 'compressed'.

DO sometimes run into home sockets and such where the
screw-down has a sort of bronze/brass PLATE under it.
Put the wire under the plate. It creates spring-tension
that'll greatly reduce the 'compression' issue.

Note that 'tinning' the stranded wires DOES seem to
slow down the 'creep', if you 'tin' correctly
(meaning JUST enough solder to solidify/bond, not
big blobs). IMHO, house-wiring should be done almost
entirely with SOLID wire though. Alas CORROSION like
you'd get on sea-coasts can STILL ruin things. For
that a VERY thin coat of solder serves well - wipe
on a little flux and LIGHTLY tin and wipe. Just a
few microns.

The most horrible mistake was back when they first
introduced aluminum wiring for homes. The metal in
the sockets/switches/etc were NOT super-compatible.
Esp in 'corrosive' environs the connections would
fail quite early - and start fires.

Remember - breakers protect against SHORTS, but
can NOT detect bad connections - which get hotter
and hotter as the resistance increases.

You get what you pay for. The 'discount' stuff from
Home Despot or whatever will be 'functional', but
for HOW LONG ? Alas, if/when it fails, it really
might burn your house down.

Anyway, enough of Practical Power Electrics in
a Pi group :-)