# Soldering Oxidized and Corroded Copper Wire



## toddalin (Jan 4, 2008)

Anyone who uses direct burial, copper feed wires to power trains, lights, or whatever in the outdoor environment knows that regardless of how well you try to seal the wire, it oxidizes and corrodes within its insulation in the damp environment. The oxidation forms a dark/black film on the strands that will not take solder.

In the past, I would used sand paper or an X-acto on the wire to scrape off the film enough to get the wire to take solder.

I am now redoing my ground signals, changing the wooden stantions to concrete, and many of the wires going to the LEDs had corroded apart from their direct burial Malibu feed wires. All of the wires (even those still connected to the Malibu wire) had the oxidation film.

This wire to the LEDs is small gauge and sanding it for soldering would probably remove most of the strands. The connections at the LEDs were still good, and I really didn't want to replace the wires and deal with those again.

Having had such good luck cleaning the brass track with vinegar, Linda suggested that I try it on these wires. I put some vinegar on a paper towel and wiped the strands. This did a bit to remove the oxidation, but not enough.

So I stripped back some insulation and soaked the ends of the wires in a small cup of vinegar for two days. When I pulled it out, the copper was bright and shiny and the wire took solder like it was brand new.


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## Jerry McColgan (Feb 8, 2008)

Great information!!!

I have had that exact problem this past week and had not come up with any ideas to get those wires to accept solder.

Thanks,

Jerry


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## Mark_s (Jun 24, 2013)

Three things to try:
1) Use a liquid flux to clean the wires - something like: 
http://www.digikey.com/product-detail/en/SMD291ST2CC6/SMD291ST2CC6-ND/2350878

2) When burying the wires, take all of the joints or other areas where the insulation on the wire has been disturbed, and protect it in grease caps such as:
http://www.walmart.com/ip/19241464?...75637391&wl4=&wl5=pla&wl6=84457859111&veh=sem

3) Another thing that can help is to make certain that when selecting the wire to use outdoors, you select one which is designed and rated for buried, outdoor use, this will have a jacket on the cable which protects the copper from exposure to the environment.


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## Pete Thornton (Jan 2, 2008)

> you try to seal the wire, it oxidizes and corrodes within its insulation in the damp environment.


You actually described what happens in a boat. Think of those expensive marine objects with tons of wire on board supporting navigation, the generator, battery charging, lights, cooking, etc., etc. It's a small house and it's a damp marine environment, and not only do we have a 120V wiring system but we have a 12V system as well, with both high and low power needs. (I'd post a photo but it's not train related!)

Marine wiring is pre-tinned, and the 'tin' protects the wire from the elements inside the insulation. Go to your local West Marine store and buy some tinned copper wire.
Also read what their website says: http://www.westmarine.com/WestAdvisor/Marine-Wire-Terminal-Tech-Specs


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## John Carmichael (Jan 18, 2016)

Try this:

Put Tarnex liquid copper polish in a small cup. (Available at ACE and sometime at Walgreens)
Dip end of the the tarnished copper stranded cable in the Tarnex for twenty seconds and remove. Only cover the part you want to solder.
Immediately rinse away ALL the Tarnex with copious amounts of water.
Dry with cloth then let air dry completely.
Now solder as usual.


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## Greg Elmassian (Jan 3, 2008)

The problem with stranded wire, is that the acid will wick up into the wire, and just rinsing the outside will not remove the acid that has wicked up inside.

do the acid... rinse, then make a baking soda solution and soak it in that for a while, then rinse, then let dry.

Greg


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