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Author Topic: Black Wire Corrosion  (Read 3388 times)

wullie/mk2

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Black Wire Corrosion
« on: June 17, 2011, 12:51:25 PM »

Could somebody please tell me where on a RC system is this problem found.
Thanks, Terry.
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Roadrunner

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Re: Black Wire Corrosion
« Reply #1 on: June 17, 2011, 02:15:47 PM »

In the boat....

Battery cables, motor cables all the wiring that can be exposed to water basically..

Only way to stop or reduce it to to ensure that your boats internals remain dry, seal all the wiring up with heat shrink right up to the solder points and over contacts if possible, ensure your combing's on hatches are either big(tall) enough or sealed with Vaseline.

Best method to reduce this effect is to use silica gel packs in the boat, they will absorb the water particles (condensation) and swell up keeping the wiring dry. Once swollen replace they only have a limited life span.

If you have ingresses of water from leakage the silica gel will only do so much to reduce it but they do not act like a sponge and instantly absorb large amounts of water quickly, so insure your prop shaft is well greased up as this reduced leakage from coming up the shaft and sitting in the boat.

Salt water run boats suffer from this far quicker then boat run in fresh water.

Black cable takes quite a while to occur in either case as long as the boat is kept dry internally then you should have many happy years of sailing before any deterioration of the wiring is noticed.

RR

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wullie/mk2

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Re: Black Wire Corrosion
« Reply #2 on: June 17, 2011, 02:22:54 PM »

Thanks for that Roadrunner, I have been told that it can also happen in the transmitter, should I take it apart and check it?
Terry.
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barriew

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Re: Black Wire Corrosion
« Reply #3 on: June 17, 2011, 04:29:08 PM »

Unless its got very wet, it is unlikely to affect the transmitter.

Also, I think it is normally the negative leads that suffer the effect.

Barrie
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dodgy geezer

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Re: Black Wire Corrosion
« Reply #4 on: June 17, 2011, 05:05:29 PM »

Look at all the battery wires coming out of any battery - mainly negative but some people report positive as well. I have had it on transmitter batteries kept inside a house, so it doesn't have to have got soaked to happen.

If you find wires which are black, junk the whole length. You will be surprised how far it can go up a wire, and there are reports of it jumping across connectors.

What it is seems to be shrouded in mystery. The wires have obviously oxidised, but in an unusual way. Current flow, battery vapours and damp are all possible culprits, and there was a rumour to the effect that it was colouring chemicals in black insulated wire that was causing it (hence the name Black Wire Disease). Once started, there seems to be some kind of catalytic reaction which enables it to proceed all the way up a wire inside the insulation. Google will give you lots of theories...

Only method I know of ensuring it doesn't happen is to disconnect batteries from all wiring when not being used. But it only seems to happen with really old batteries...

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unbuiltnautilus

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Re: Black Wire Corrosion
« Reply #5 on: June 17, 2011, 05:26:09 PM »

Copper wire seems to be more at risk than the other shiney stuff, ( my knowledge on this subject is vast!!), it only seems to effect older models, by that I mean it is unlikely to effect a new radio or model, but one that has been around a while. Try fitting new batteries in an old M Series Radio, you can track the black wire all the way back to Japan :}
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dodgy geezer

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Re: Black Wire Corrosion
« Reply #6 on: June 17, 2011, 07:32:54 PM »

This seems to be quite a good overview. I think perhaps that I ought to join this club...

http://www.barbadosrc.org/misc/blackwire.php

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Xtian29

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Re: Black Wire Corrosion
« Reply #7 on: June 17, 2011, 10:02:18 PM »

The problem can be reduced by good sealing of connections as already mentioned with heatshrink tube, especially the type that has a layer of glue inside.

In addition, it is a good idea to make the solder or crimp connection on the wire and then soak it in WD40, or thin oil and let that capillary up the wire for a few inches. (just like the salt water will do if it is given the chance) Then liberally coat the terminal/pin whatever in silicone grease, which is a bit like Vaselene to look at, but way better. Think of it as WD40 in grease form. Better still, if crimping, coat the bare wire end in silicone grease before you crimp the terminal, as well as all the above! Wire ends treated this way will be massively protected from corrosion and are generally hassle free in horrible environments for months if not years! (salt water/boats etc)

In all cases the copper starts corroding at any point that it is exposed. Even the usual PVC insulation is to some extent porous, so we are on a hiding to nothing if we run the boats in salt water or let batteries spill acid or puke out acidic fumes. Cheap equipment wire is only bare copper strands. One step better is tin plated copper wire, which is virtually the same price, followed by silver plated copper wire, which is ten times the price, and is usually insulated with PTFE into the bargain, which makes it very rugged indeed! (which is why it was used in missile (Polaris) wiring looms.) If you have the money, RS components stock it! (part no 726-7400 for some thin pink stuff at 8 for 25 metres). You can even chuck so much current down it that it glows red hot, and unless you actually blow it like a fuse it will still be intact, but the silver plating will have evaporated, but that is way better than being on fire and shorting out to it's surroundings like it's PVC counterpart would be doing. It is brilliant stuff. It comes in lots of colours and sizes, but costs the earth.....the pink stuff is cheaper because it is the main colour the military uses....almost all the wires they use are the same colour and are marked with slide on markers for identification......Oh, and if you do try the glowing wire trick, don't breathe the white smoke that belches out of each end of the wire.....it may shorten your life a tad.
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derekwarner

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Re: Black Wire Corrosion
« Reply #8 on: June 18, 2011, 02:16:24 AM »

No corrosion here  >>:-(..........this is the remains of a wiring loom from a Harpoon missile [just don't :police: ask where it came from]

It has approx 30 co-axial individual cores......silver plated copper multi core inner, teflon coated, aluminium shielded, teflon coated, silver plated multi core copper outer woven shielding + an  outer... outer teflon coating...the larger cores are still only 0.110" on the major outer teflon coating diameter

Each of the 30 cores also have individual colour striped codings.....so colour blind people need not apply for an assembly job at the FMC missile factory..... {-) .......

The loom by nature of it's design is expendable as it is blown away  <*< when the Harpoon missile strikes the chosen target.........but 30 years ago the loom had a replacement cost of $6,000.00 AUD...........Derek  :-X
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Derek Warner

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rockets

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Re: Black Wire Corrosion
« Reply #9 on: June 20, 2011, 08:37:06 PM »

I had it happen on a BSA motorbike, just about every bloody wire was knackered!

I use aircraft wiring in my models, haven't had any problems with corrosion as yet. Just like a previous post, don't ask where it comes from!

Rockets.
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Paul S

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Re: Black Wire Corrosion
« Reply #10 on: June 22, 2011, 11:31:14 AM »

Hi Guys.

Had this problem since I bought my first RC back in 1973.  'Black wire Blues' has probably occuppied more editorial space over the years than I care to remember.  Doesn't matter if it's a car, boat or aircraft it still accurs.   Never had it occur on power batteries only the RC, Transmitters, receiver installations etc.  Have tried all the tricks afore mentioned in the pass and it still occurs.  Yes, in older batteries and only on the negative side.  Just had to replace the negative wire all the way from the Battery to the receiver, inline socket as well, all consumed.  It's obviously a cemical reaction caused by some potential difference that exists even in an 'off' circuit.  Who knows!!!  I agree, if your not using the model of TX then take out the batteries.  Tell tale signs on batteries are white crystals around the positive pip, if you see these chuck-m.   Seen so many theories over the years, but no answer that works other than battery removal.  Be warned about WD40, it can make a very good insulator, better use Switch lubricant.

Cheers
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Colin Bishop

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Re: Black Wire Corrosion
« Reply #11 on: June 22, 2011, 11:45:46 AM »

The lighting wiring in my full size boat went that way too.

Colin
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