Corrosion in wire.
 

I'm in the process of fitting a different ECU to the old car and bought a
NOS engine loom to modify. Basically just change the ECU multiplug and add
a couple of sensors. The loom came in a sealed plastic bag with the
original Rover sticker on it. And appeared to be as it left the factory -
still nice and flexible. But on hacking off the Lucas multiplug to replace
with the required D37 connector, I was surprised to find some of the
conductors lightly corroded. Only a few, though - most were bright copper.
I've seen this on old car wiring where it's been exposed to damp etc, but
this appeared to have been well stored, even although more than 20 years
old.

Any tips for removing the corrosion as it has to be soldered rather than
crimped as the original plug was. Short of just scraping it off?

--
*Just give me chocolate and nobody gets hurt

Dave Plowman London SW
To e-mail, change noise into sound.

Corrosion in wire.
 

On Tue, 28 Jul 2009 23:37:31 +0100, Dave Plowman (News) wrote:
Any tips for removing the corrosion as it has to be soldered rather than
crimped as the original plug was. Short of just scraping it off?

Hack it off if there's enough slack. I've had success with just scraping
before - but I suspect it's nowhere near as mechanically strong as a
'proper' joint, even if it ends up electrically OK, and might just be
asking for trouble 20 years down the line.

Corrosion in wire.
 

"Jules" wrote in message
ail.com...
On Tue, 28 Jul 2009 23:37:31 +0100, Dave Plowman (News) wrote:
Any tips for removing the corrosion as it has to be soldered rather than
crimped as the original plug was. Short of just scraping it off?

Hack it off if there's enough slack. I've had success with just scraping
before - but I suspect it's nowhere near as mechanically strong as a
'proper' joint, even if it ends up electrically OK, and might just be
asking for trouble 20 years down the line.

Rub them between two pieces of very fine emery paper.

Don

Corrosion in wire.
 

In article , Donwill popple
@diddle .dot wrote:

"Jules" wrote in message
ail.com...
On Tue, 28 Jul 2009 23:37:31 +0100, Dave Plowman (News) wrote:
Any tips for removing the corrosion as it has to be soldered rather
than crimped as the original plug was. Short of just scraping it off?

Hack it off if there's enough slack.

Sadly, there's not. And experience with this sort of corrosion says it
usually goes quite a way in. But after cleaning the end and making the
correction the circuit shows a decent low resistance on my ESR meter. But
most of the sensors have a fairly high resistance anyway - so a few ohms
probably wouldn't matter unless it got worse. The injector drive circuits
are fine - and they do need to be low impedance.

I've had success with just
scraping before - but I suspect it's nowhere near as mechanically
strong as a 'proper' joint, even if it ends up electrically OK, and
might just be asking for trouble 20 years down the line.

I'll be dead by then. ;-)

Rub them between two pieces of very fine emery paper.

I usually just scrape with the edge of a blade. I was hoping someone had a
chemical solution. That didn't cause problems later on - like an
aggressive flux can if not completely removed afterwards.

Don

--
*Learn from your parents' mistakes - use birth control

Dave Plowman London SW
To e-mail, change noise into sound.

Corrosion in wire.
 

On Wed, 29 Jul 2009 08:34:21 +0100, Dave Plowman (News) wrote:

In article , Donwill popple
@diddle .dot wrote:

"Jules" wrote in message
ail.com...
On Tue, 28 Jul 2009 23:37:31 +0100, Dave Plowman (News) wrote:
Any tips for removing the corrosion as it has to be soldered rather
than crimped as the original plug was. Short of just scraping it off?

Hack it off if there's enough slack.

Sadly, there's not. And experience with this sort of corrosion says it
usually goes quite a way in.

Yes, I usually find that, too. If it's one or two wires I'll usually cut
the damage out and then solder/heatshrink some short runs of
replacement wire in - I'd built up quite a collection of different
wire/stripe colour combinations in the junk box before I moved
overseas :)

Pain in the butt doing it for big multi-way runs, though.

I've had success with just
scraping before - but I suspect it's nowhere near as mechanically
strong as a 'proper' joint, even if it ends up electrically OK, and
might just be asking for trouble 20 years down the line.

I'll be dead by then. ;-)

Sure, leave your mess for someone else to sort out ;-)

I was hoping someone had a chemical solution.

I'd be interested to know if there is one, too. I suppose in principle
it's no different to removing corrosion from any other metal, with the
bonus that it shouldn't matter if there's pitting left behind as it's not
a cosmetic thing.

Problem is, I assume that the corrosion weakens the wire as well as making
it harder to solder to - so if it goes in a few inches it's just asking
for failure at some point - and any chemical treatment probably won't
reach under the insulation...

cheers

Jules

Corrosion in wire.
 

On Wed, 29 Jul 2009 08:34:21 +0100, "Dave Plowman (News)"
wrote:

I usually just scrape with the edge of a blade. I was hoping someone had a
chemical solution. That didn't cause problems later on - like an
aggressive flux can if not completely removed afterwards.

I've used fibreglass pencils with success
http://cpc.farnell.com/_/10191/fibre...l/dp/SABU10191
just stroke along the exposed wires. Easier than glasspaper and less
damaging than a knife.

(free delivery today for all CPC orders)

Corrosion in wire.
 

In article ,
Peter Parry wrote:
I've used fibreglass pencils with success
http://cpc.farnell.com/_/10191/fibre...l/dp/SABU10191
just stroke along the exposed wires. Easier than glasspaper and less
damaging than a knife.

They make me itch...

(free delivery today for all CPC orders)

But not the handling charge on small orders.

--
*Never miss a good chance to shut up *

Dave Plowman London SW
To e-mail, change noise into sound.

Corrosion in wire.
 

On Wed, 29 Jul 2009 14:27:04 +0100, "Dave Plowman (News)"
wrote:


(free delivery today for all CPC orders)

But not the handling charge on small orders.

No handling charge today (although it shows). Removed after order as
it says on the little box to the right.

Corrosion in wire.
 

In article , Dave Plowman (News)
writes
In article ,
Peter Parry wrote:
I've used fibreglass pencils with success
http://cpc.farnell.com/_/10191/fibre...l/dp/SABU10191
just stroke along the exposed wires. Easier than glasspaper and less
damaging than a knife.

They make me itch...

(free delivery today for all CPC orders)

But not the handling charge on small orders.

They say that all delivery and handling charges are waived today as long
as the code provided on the front page is entered in the 'Special
Instructions' box at checkout.

Problem is that there is no Special Instructions box at checkout, only
Order Comments and Delivery Instructions. From speaking to them,
Delivery Instructions is where to put the code.

Unfortunately, the discount will only be applied when the card is
debited meaning that your order confirmation email will still show the
handling charge.

An awkward and uncertain process to say the least but I have a call
logged to confirm that my order meets their criteria.

Thanks Peter.
--
fred
BBC3, ITV2/3/4, channels going to the DOGs

Corrosion in wire.
 

In article ,
fred wrote:
But not the handling charge on small orders.

They say that all delivery and handling charges are waived today as long
as the code provided on the front page is entered in the 'Special
Instructions' box at checkout.

Problem is that there is no Special Instructions box at checkout, only
Order Comments and Delivery Instructions. From speaking to them,
Delivery Instructions is where to put the code.

Unfortunately, the discount will only be applied when the card is
debited meaning that your order confirmation email will still show the
handling charge.

An awkward and uncertain process to say the least but I have a call
logged to confirm that my order meets their criteria.

Bugger. Think I may have cocked things up.

--
*Reality is the illusion that occurs due to the lack of alcohol *

Dave Plowman London SW
To e-mail, change noise into sound.

Corrosion in wire.
 

Peter Parry wrote:
On Wed, 29 Jul 2009 08:34:21 +0100, "Dave Plowman (News)"
wrote:

I usually just scrape with the edge of a blade. I was hoping someone had a
chemical solution. That didn't cause problems later on - like an
aggressive flux can if not completely removed afterwards.

I've used fibreglass pencils with success
http://cpc.farnell.com/_/10191/fibre...l/dp/SABU10191
just stroke along the exposed wires. Easier than glasspaper and less
damaging than a knife.

Thanks, Peter. I had the same problem and also the same fibreglass
scratch brush - just never put the two together. Stranded copper that
had been black with corrosion came clean enough for either soldering or
crimping.

For other applications, CPC also have brass bristle refills... but has
anyone seen the same in stainless steel recently? They seem to have
disappeared from the market.


--
Ian White

Corrosion in wire.
 

In article , Dave Plowman (News)
writes
In article ,
fred wrote:
But not the handling charge on small orders.

They say that all delivery and handling charges are waived today as long
as the code provided on the front page is entered in the 'Special
Instructions' box at checkout.

Problem is that there is no Special Instructions box at checkout, only
Order Comments and Delivery Instructions. From speaking to them,
Delivery Instructions is where to put the code.

Unfortunately, the discount will only be applied when the card is
debited meaning that your order confirmation email will still show the
handling charge.

An awkward and uncertain process to say the least but I have a call
logged to confirm that my order meets their criteria.

Bugger. Think I may have cocked things up.

Give them a call and they may take pity on you, it's not a particularly
clear procedure. Ah, just noticed the lines close at 7pm so it will need
to be tomorrow.
--
fred
BBC3, ITV2/3/4, channels going to the DOGs

Corrosion in wire.
 

On 2009-07-29, Dave Plowman (News) wrote:
In article , Donwill popple
@diddle .dot wrote:

"Jules" wrote in message
ail.com...
On Tue, 28 Jul 2009 23:37:31 +0100, Dave Plowman (News) wrote:
Any tips for removing the corrosion as it has to be soldered rather
than crimped as the original plug was. Short of just scraping it off?

Hack it off if there's enough slack.

Sadly, there's not. And experience with this sort of corrosion says it
usually goes quite a way in. But after cleaning the end and making the
correction the circuit shows a decent low resistance on my ESR meter. But
most of the sensors have a fairly high resistance anyway - so a few ohms
probably wouldn't matter unless it got worse. The injector drive circuits
are fine - and they do need to be low impedance.

I've had success with just
scraping before - but I suspect it's nowhere near as mechanically
strong as a 'proper' joint, even if it ends up electrically OK, and
might just be asking for trouble 20 years down the line.

I'll be dead by then. ;-)

Rub them between two pieces of very fine emery paper.

I usually just scrape with the edge of a blade. I was hoping someone had a
chemical solution. That didn't cause problems later on - like an
aggressive flux can if not completely removed afterwards.

Don


I've come across this many times with old wiring looms. The copper
oxide film appears to form all along the wires, under the sheath. I dip
the exposed copper in warm dilute acid: usually citric - sulphuric or
hydrochloric would be quicker. (IIRC sulphamic acid doesn't work.) Stop
when the copper is errm, copper cloured. Rinse it well afterwards with
boiling water. Scraping is ok for single core, but not good enough
for soldering multicore. I guess that a fibreglass brush could work
on multicore.

--
Jan

Corrosion in wire.
 

In article ,
Jan Wysocki wrote:
I usually just scrape with the edge of a blade. I was hoping someone had a
chemical solution. That didn't cause problems later on - like an
aggressive flux can if not completely removed afterwards.

Don


I've come across this many times with old wiring looms. The copper
oxide film appears to form all along the wires, under the sheath. I dip
the exposed copper in warm dilute acid: usually citric - sulphuric or
hydrochloric would be quicker. (IIRC sulphamic acid doesn't work.) Stop
when the copper is errm, copper cloured. Rinse it well afterwards with
boiling water.

Thanks - I'll give that a try when I next come across it.

Scraping is ok for single core, but not good enough
for soldering multicore. I guess that a fibreglass brush could work
on multicore.

--
*I wonder how much deeper the ocean would be without sponges*

Dave Plowman London SW
To e-mail, change noise into sound.