Impossible to solder old wire

[SimonTHK]

UPDATED (I found 1 usefull way to do it. There is also alot of other possible ways to do it if you read through the thread):

-Take each single copper wire apart from each others.
-Put the wire 10-20 minutes in salt acid 30% which can be bought from local hardware store cheap.
-Use protection glasses.
-Use toilet paper or something and clean the rest of the salt acid away, you will also see alot of dirt coming off, get it all off.
-In my case, the tin wouldnt just float on, but when I applied solder flux it came on like if it was made for it, which it also am


I have this old wire from 1991 and it is from an old jetski. The wire are not to be changed.
I need solder on the end, but I find it impossible. I tried for two hours, I tried to use a knife and scratch the black colour off, I have no better tool for that. I also tried to place it in gas, no clue if that should help but it didnt. At last I put it in a glass of cola and dropped salt xD have to try something.
I have no flux, but my tin is with flux inside.

What can I do? I am going nuts to be held back in my project at this point because of something this annoying

 

[SimonTHK]

I do have professional solder iron from ERSA

 

[dknguyen]

Get some really active flux and use a LOT of it while trying to solder it. That might help. It makes take a bunch of flux and heating of the flux and adding more flux and more heating before the wire is clean enough for solder to adhere. The flux core of your solder is not going to be enough. Heck, it's barely enough for soldering to a nice clean surface!

 

[DirtyLude]

Ya, I had to do this for a sensor wire that the shielding had frayed on. The wire was so corroded solder would not stick. I had to use a load of flux on it and it managed to work.

There might be something else you can do that's better, maybe a light acid soak or something, but a load of flux will eventually work.

 

[SimonTHK]

I will try this thanks

I have heard that if I can heat the flux up with and old soldering iron then I can dip the wire in the boiling flux what ya think?

 

[SimonTHK]

Use some kind of small metal bath to have the solder in

 

[crutschow]

If it's not an electronics board you could use acid flux which is stronger than rosin flux. For electronics, you should only use rosin flux. Be sure to thoroughly wash acid flux off the joint after you finish soldering.

 

[Sceadwian]

There's nothing wrong with using acid flux for electronics if you can guarantee that you can rinse the flux residue off then again this isn't really an 'electronics' application so much as it is a general electrical one.
You need to physically clean the entire wire better, scraping won't cut it, use something like scotch bright pads, perhaps clearning it up more afterwards with rough cloth. It can't be simply 'clean to see' soldering requires 'clean' to a degree that you can't visually inspect for with older wires, there could easily be a basic oxide layer you're missing. Get yourself a small tube/bottle of mildly activated paste flux and try again. Soldering wires that have been in the real world for a bit requires extra cleaning steps and more activated fluxes than fresh solder joints.


Just to cover the bases, is this copper wire being soldered to a tinned or copper junction?

 

[BeeBop]

What works for me, and I've seen some badly corroded, oxidized, ugly things, is unrolling the strands, and laying the wire flat on the bench. Then scraping along the strands with the edge of a box-cutter - in one direction - away from the insulation - while rolling the wire back and forth slowly.

I've never been without flux, and apply liberally after a few seconds of the above action. I always get a small blob of fresh solder on the tip of my iron before trying to heat the wire, and make sure the flux stays fluid until the wire is hot enough to melt the solder (by applying more flus, if need be.)

If you really don't want to go and get some flux, then you can probably still do it, but you'll have to flux around with the scraping for a fluxing long time.

 

[Rescue1]

Whenever I have to wire things into my boat or trailer I dip the stripped end into some battery acid for about 10 seconds, then a quick water dip and the copper is like new. Just be careful as sulfuric acid is nasty stuff. Also, while on the water one time I had to redo a connection and pepsi worked. It was slow but worked, enough to get me back anyway...

 

[ericgibbs]

I have this old wire from 1991 and it is from an old jetski. The wire are not to be changed.
I need solder on the end, but I find it impossible. I tried for two hours, I tried to use a knife and scratch the black colour off, I have no better tool for that. I also tried to place it in gas, no clue if that should help but it didnt. At last I put it in a glass of cola and dropped salt xD have to try something.
I have no flux, but my tin is with flux inside.

What can I do? I am going nuts to be held back in my project at this point because of something this annoying

hi Simon,
From your local hardware shop get some 'plumbers paste', its usually a small tin about the size of shoe polish tin.

Use a rag to smear a light coating onto the wire, I have used this paste method successfully many times on marine applications when other methods have failed.

Its important to remove any residual paste from the work piece after soldering, a wipe with a rag moistened with methylated spirit is OK.

You will find the paste handy to clean the tip of your solder iron when it gets covered in crud, wipe the tip after dipping.

 

[SimonTHK]

There's nothing wrong with using acid flux for electronics if you can guarantee that you can rinse the flux residue off then again this isn't really an 'electronics' application so much as it is a general electrical one.
You need to physically clean the entire wire better, scraping won't cut it, use something like scotch bright pads, perhaps clearning it up more afterwards with rough cloth. It can't be simply 'clean to see' soldering requires 'clean' to a degree that you can't visually inspect for with older wires, there could easily be a basic oxide layer you're missing. Get yourself a small tube/bottle of mildly activated paste flux and try again. Soldering wires that have been in the real world for a bit requires extra cleaning steps and more activated fluxes than fresh solder joints.


Just to cover the bases, is this copper wire being soldered to a tinned or copper junction?

It has to be soldered to another copper wire

 

[SimonTHK]

hi Simon,
From your local hardware shop get some 'plumbers paste', its usually a small tin about the size of shoe polish tin.

Use a rag to smear a light coating onto the wire, I have used this paste method successfully many times on marine applications when other methods have failed.

Its important to remove any residual paste from the work piece after soldering, a wipe with a rag moistened with methylated spirit is OK.

You will find the paste handy to clean the tip of your solder iron when it gets covered in crud, wipe the tip after dipping.

YouTube - Plumber's Hemp and Paste

I guess it is this paste in the video, paste I have worked with alot But how exactly do you use it for this purpose? Only to clean the wire or do you put it on and then solder on it? How much heat you apply, and do you use flux in the process aswell.
I have found every answear from you helpfull so I want to try this out aswell.

 

[ericgibbs]

YouTube - Plumber's Hemp and Paste

I guess it is this paste in the video, paste I have worked with alot But how exactly do you use it for this purpose? Only to clean the wire or do you put it on and then solder on it? How much heat you apply, and do you use flux in the process aswell.
I have found every answear from you helpfull so I want to try this out aswell.

hi Simon.
Not that sort of plumbers paste in the video , thats for sealing pipe threads.!!!

Its the flux type plumbers paste, apply very lightly to the wire with a rag and then solder as normal with your solder..

 

[Mosaic]

If it's copper to copper, clean it, flux it, solder it. Use 60/40 Lead based solder for better wettability than lead free.

Copper oxide is black.

If the wire is not copper, eg Aluminum, then u gonna have to crimp it.

Aluminum corrosion is white.

I had to solder an aluminum wire once. I electroplated it first with copper then soldered it...10 years now and it still works.


Edit:
One other possibility is if the wire is heavy gauge, you aren't getting enough heat into the joint. Then u need to get a higher wattage iron!

 

[SimonTHK]

im trying with salt acid now, since this was easy to try The salt acid 30% is bobling and stuff making noise I can hear from 2 meters away. I cant wait to see the wire in 20 minutes

 

[SimonTHK]

So nice this salt acid 30% just completely owned that bad black corrosion. So my guide that works on a very bad wire would be like this:

-Take each single copper wire apart from each others.
-Put the wire 10-20 minutes in salt acid 30% which can be bought from local hardware store cheap.
-Use protection glasses.
-Use toilet paper or something and clean the rest of the salt acid away, you will also see alot of dirt coming off, get it all off.
-In my case, the tin wouldnt just float on, but when I applied solder flux it came on like if it was made for it, which it also am

So ok I had to buy solder flux and salt acid, but this stuff last for years

 

[SimonTHK]

hi Simon.
Not that sort of plumbers paste in the video , thats for sealing pipe threads.!!!

Its the flux type plumbers paste, apply very lightly to the wire with a rag and then solder as normal with your solder..

Hi Eric, I was not able to find this plummers paste but as you see I figured something else out

 

[SimonTHK]

I just tried with 1 of the other wires that was black. This wire only needed 2 minutes in acid and didnt need flux to add the tin.

 

[Sceadwian]

You should use flux anyway if you have any avaialble, you may have soldered but if there isn't good fluxing it'll be a weak joint.