Clive 13 Posted April 12, 2016 Share Posted April 12, 2016 One for Wheels - I hope! I tried the vinegar/salt wash and bicarb rinse yesterday on some wires that were badly tarnished. It worked really well on the positive which came up clean but the negative was still badly tarnished. Is my only option to run a positive current down the negative line and have a negative in the vinegar/salt bath? I have tried other stuff like Silver Dip with little success. Flux also doesn't cut the mustard. Quote Link to post Share on other sites
Vorpal Blade 89 Posted April 12, 2016 Share Posted April 12, 2016 It maybe better to replace the buggered copper wire with shiny new tinned copper and start again. Quote Link to post Share on other sites
Clive 13 Posted April 12, 2016 Author Share Posted April 12, 2016 Agreed only I am not up to that 2/3 day exercise yet!! Quote Link to post Share on other sites
SloopJohnB 322 Posted April 12, 2016 Share Posted April 12, 2016 Have you tried coke it works on everything else. I have scraped the black off with a knife but you don't get a prefect soldered joint. Quote Link to post Share on other sites
Vorpal Blade 89 Posted April 12, 2016 Share Posted April 12, 2016 Either way its still crappy old corroded copper wire and its only going to corrode more no matter how well you solder. Ive just been through this exersize on VB with a bunch of old existing wiring and have found its much less problematic to just pull out the old sh*t and replace it with good stuff, particularly so if the wiring has been exposed to a salt water bath as might be the case on DD. Quote Link to post Share on other sites
wheels 543 Posted April 12, 2016 Share Posted April 12, 2016 Both Sulphates and Chlorides can cause the black oxide to form on copper wire. In our case, being marine and thus Sodium Chloride present, I expect it will be a Chloride. Just why it creeps along the negative wire? I have not yet come across any one that really can answer that in anyway convincing. Lots of guesses. However, I expect it has something to do with an electrolytic action taking place.This is the very reason why Tinned copper is used. I have used pure copper myself, but the terminations need to be fully sealed and making such connections takes time. Failure of that connection results in the wire going black. In the end, that black will cause the wire to fail. It is often called "Black Rot" in the electrical world, because it does eventually rot the wire.Cleaning the end of the wire does not clean the entire length of course. However, addressing the cleaning part. You are on the right track. I suggest you heat the Vinegar/Salt solution which will cause it to be a little more aggressive. Or you could try Lemon Juice which is a stronger Acid. Other things are.......Solder paste used for Silver solder used in Plumbing, which is Borax.Ferric iii Chloride, which is used to etch copper PCB's.Sulfamic Acid(CLR) ,. Hydrochloric Acid is the best, especially for Chloride based corrosion, but will be far too aggressive in this case. It would have to be heavily diluted. This is what used to be used in the old days for soldering spouting etc. Quote Link to post Share on other sites
erice 732 Posted April 12, 2016 Share Posted April 12, 2016 . Hydrochloric Acid is the best, especially for Chloride based corrosion, but will be far too aggressive in this case. It would have to be heavily diluted. This is what used to be used in the old days for soldering spouting etc. just an fyi sold as "killed spirits" as the acid was killed by dropping in blocks of zinc great for soldering galvanised guttering not recommended for soldering cat gut In an emergency you can take a small amount of battery acid and a zinc coated bolt to get a flux. http://www.willingtons.com/mymac/soldering.htm all usual legal disclaimers apply Quote Link to post Share on other sites
Clive 13 Posted April 12, 2016 Author Share Posted April 12, 2016 Thanks Wheels - "Black Rot" I didn't realise that, I assumed that as long as then ends were good it wouldn't make a lot of difference. Quote Link to post Share on other sites
wheels 543 Posted April 12, 2016 Share Posted April 12, 2016 How many metres do you need and what conductor size. I am not sure if I have any at the mo, be we often get tinned wire dropped off. I can have a look and see what we have. I know a huge heap of it went to scrap a few weeks ago, which annoyed me. I said to the guy handling that side to hold into Tinned cable in any decent length.By the way everyone, I do currently have a heap of Battery cable. Not tinned.Also, stacks of 2+ m lengths of aluminium extrusion they use for mounting solar panels on House roofs.We get so much stuff that I almost cry when I see it going to be scrapped. I have this problem of wanting to save it all. But I just can't. Quote Link to post Share on other sites
Island Time 1,239 Posted April 13, 2016 Share Posted April 13, 2016 Yep, cables with black rot are stuffed. Replace them. They are not good conductors, and waste your battery power. Cleaning the ends by soaking in various substances as above, or liquid soldering flux is a temporary solution at best. I usually have reels of the common sizes (1mm, 2mm, 4mm at least) and some others if anyone wants some. All proper marine grade, tinned cable.... Quote Link to post Share on other sites
Clive 13 Posted April 13, 2016 Author Share Posted April 13, 2016 thanks for the offer guys - max length is 6m and highest amps is only 0.5 - 2 core. Would that make it 4.0 conductor size? Quote Link to post Share on other sites
Island Time 1,239 Posted April 13, 2016 Share Posted April 13, 2016 Clive, is that 6m to the power source or 3 (have to measure both the + and the - side of the circuit, so 3m to the batt is a 6 m circuit).Wire sizes are normally expressed in AWG, or metric. As a 4.0 in one is completely different to a 4.0 in the other, it's critical to state which one you are referring to. Also, I don't normally use anything less than 1mm2 just because of structural integrity. Really small cables are easily broken while running them through the often difficult/convoluted routes taken by boat wiring... Quote Link to post Share on other sites
Island Time 1,239 Posted April 13, 2016 Share Posted April 13, 2016 And for your example, for a 6m return length, I'd use 1mm2 or 1.5mm2, which is AWG 15-17. In AWG, the lower the number, the bigger the cable... 1 Quote Link to post Share on other sites
Beccara 25 Posted April 13, 2016 Share Posted April 13, 2016 Yeah assuming worst case of 6m length either 1mm2 or 1.5mm2 would work just fine. Normally you size the cable for the current to maintain less than 3% voltage drop which you can calc here http://www.calculator.net/voltage-drop-calculator.html 0.5amp on 1mm2 for 6m gives you a drop of 1.67% however if that load is 1amp the 1mm2 cable will give you 3.33% drop so you'd need to goto 1.5mm2 cable. As a personal preference i try to keep the number of different sized cables on board low so i have wired for 2mm/6mm/25mm/50mm Quote Link to post Share on other sites
Island Time 1,239 Posted April 13, 2016 Share Posted April 13, 2016 That's not a bad calculator Beccara, but after my notes above, just be aware that to confuse the issue, that particular calculator DOES NOT use full circuit length, only the one side. Just a heads up, that's all 1 Quote Link to post Share on other sites
Clive 13 Posted April 14, 2016 Author Share Posted April 14, 2016 Thanks for the info. 6m return length - fortunately the 6 core cable running across the boat is still good so it's just the 2 core to the lights/etc that have gone bad.. Quote Link to post Share on other sites
waikiore 400 Posted April 14, 2016 Share Posted April 14, 2016 monohulls are drier, just saying Quote Link to post Share on other sites
Ed 143 Posted April 14, 2016 Share Posted April 14, 2016 ...and slower, just saying???? Quote Link to post Share on other sites
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