Author Topic: Black Wire Corrosion  (Read 5025 times)

Offline Mel Garlick

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Black Wire Corrosion
« on: 09, June 2006, 04:43:59 PM »
A warning to all to periodically check your connections!

The attached picture is the battery lead from a pack that was purchased at last years Nats, used until January and then stored in the model for two months.

When I pulled the connectors apart it left one of the socket pins in the plug. It was corroded a nasty green colour and upon stripping the wire you can see why.

I'm fully aware of black wire corrosion and regularly check the leads but I'm still surprised that this happened in such a short space of time.

The model was hung off the rafters in a relatively dry double garage come workshop which is the best option unless you can keep your models in the house.

I normally disconnect the leads when storing but didn't think a couple of months would matter.

Just goes to show we should take nothing for granted.

Mel

Offline Mike Wood

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Re: Black Wire Corrosion
« Reply #1 on: 09, June 2006, 05:39:56 PM »
I was going to ask if it had been stored in a garage.

Every case of black wire that I have been told about or seen first hand has been
where it has been stored in a garage.

Is this a coincidence or a major contributary factor to black wire syndrome?

Mike
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Offline Mel Garlick

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Re: Black Wire Corrosion
« Reply #2 on: 09, June 2006, 07:34:13 PM »
As far as I know it's never been satisfactorily explained but certainly a humid (or damp) atmosphere is a contributory factor. It doesn't seem to ever happen if the plugs are left unconnected though.
(Someone will now tell me it does)

Mel

Offline Bill Michie

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Re: Black Wire Corrosion
« Reply #3 on: 12, June 2006, 07:26:52 PM »
Hi Mel. Next thing is to check for the same thing, back through/ into your system. Neg Lead Corrosion has been known, in extreme cases, to go right back as far as the Rx, past the switch etc. I've been led to believe, that contributory factors are: moisture present allowing vapours/ electrolyte to set up an electrochemical reaction that starts the corrosion off. If I store my models ( also in the grudge) for any length of time I either remove the batteries or at least disconnect them. I must say though, the rapidity of this (your) corrosion seems much quicker than normal.
Any  electrochemical engineers care to add....................
Regards, Bill.
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Offline Mel Garlick

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Re: Black Wire Corrosion
« Reply #4 on: 12, June 2006, 07:50:20 PM »
Hi Bill,

Don't worry, I'm ahead of you there! I've junked the switch just in case but stripping the wires revealed clean shiny copper so it appears to have stopped at the plug and socket.

The interesting thing is that although the negative wire was black (which I believe it always is with bwc) it was the positive pin in the socket which had corroded and snapped off in the plug despite the rest of the positive lead being bright copper. Any ideas?
 
Mel

Offline Ashley Hoyland

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Re: Black Wire Corrosion
« Reply #5 on: 12, June 2006, 07:56:28 PM »
I first suffered from BWS (black wire syndrome) way back in 1964 when we were using DEAC button cells, but no support came forward to back up my evidence or theories.  The next time this emerged was in the early seventies when Nottingham University were involved in some investigation, but by all accounts no conclusion was reached. 

The strangest case I have experienced was when I moved into the cottage with no where else to charge my nicads but in the garage.  I experienced BWS at the JR charger end of the charge cable where the plastic sleeving had been damaged where it entered the charger, the Rx charging plug end of the same cable showing no evidence of the BWS.  This suggests that it has nothing to do with venting of cells, and the only common factor for me has been damp conditions, but why always the black wire?

Is there any connection between this, and car manufacturers when they went through a period of wiring vehicles positive earth to reduce body corrosion?

Ashley
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Offline Stuart Mellor

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Re: Black Wire Corrosion
« Reply #6 on: 13, June 2006, 09:04:11 PM »
Hi all,
Have always kept my models in the house & have never suffered BWC- 'cept once.

In 1967, using the fabulous all new DEAC button cells & after having flown my model all year the servos appeared sluggish. The battery pack,wrapped in a plastic bag, under the tank had chaffed & fue l(no nitro)  had at some time previously entered the bag. The wires from the battery were jet black for their entire length - I can't remember if the positive wire was also affected. I thought at the time it was the methanol that had caused the corrosion, but since methanol attracts moisture it could have been that.

It seems most bwc happens to models kept in sheds or garages so damp may well be the culprit...........
regards
Stuart
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