Flux or trix for soldering old gibson shielded wire

[David King]

I was helping a friend rewire an old hollow body with new pots, toggle and 6 way rotary switch. We wanted to keep the original shielded wire coming out of the pickups but I had a heck of a time tinning the shield as it was so oxidized. I ended up combing out the last 1/2" of the shield and sanding it all down to bare copper before I could get any solder to stick. I just wonder if there's a liquid deoxidizer/cleaner or flux that can cut right through that muck.

I was tempted to dip the end in jeweler's flux but I've always heard that acid is a no-no in electrical solder connections. Is there an easier way to deal with this?

Thanks

[Spence]

It sounds like your iron just isn't hot enough.

[Joe Gwinn]

I was helping a friend rewire an old hollow body with new pots, toggle and 6 way rotary switch. We wanted to keep the original shielded wire coming out of the pickups but I had a heck of a time tinning the shield as it was so oxidized. I ended up combing out the last 1/2" of the shield and sanding it all down to bare copper before I could get any solder to stick. I just wonder if there's a liquid deoxidizer/cleaner or flux that can cut right through that muck.

The comb-and-sand approach is correct. Any fluid used on stranded wire or a braided shield will wick up into the wire or shield and become impossible to remove, so one must use something that need not be removed.

There are a number of rosin-based fluxes that are OK. In extreme cases, I've used plumbers grease flux (the stuff intended for lead-tin solder on copper pipe).

I was tempted to dip the end in jeweler's flux but I've always heard that acid is a no-no in electrical solder connections. Is there an easier way to deal with this?

If "jewler's flux" is what I think it is, it will badly corrode everything nearby.

[David King]

Thanks guys.
I know the newer plumbing fluxes are all water soluble but I doubt water is a good idea, perhaps a small jet of steam would work out.

[David Schwab]

I find it necessary to sand, scratch, or otherwise rough up the back of the pots a lot of the time.

I'm starting to not solder to the pots anymore. I use one of those solder lugs around the threaded shaft now.

[Spence]

There's no need to go sanding your pots. Gibson and Fender never did that so how could they manage in the dark ages of the 20 century? They just had irons that are hot enough. Just melt a quantity of solder with a flux core on the pot until it pools out. This will not damage the pot if you get it right. This isn't difficult to do

[Tom Phillips]

Some pot bodies don't take solder well.

There's no need to go sanding your pots. Gibson and Fender never did that so how could they manage in the dark ages of the 20 century? They just had irons that are hot enough. Just melt a quantity of solder with a flux core on the pot until it pools out. This will not damage the pot if you get it right. This isn't difficult to do

I understand but there is something on some brands of modern pots that will not accept solder very easily if at all. I can solder to the bodies of most old pots just fine. Even without redorting to the big iron that I use to solder to chassis. But even the big one will not allow me to solder to some modern pot bodies without sanding them. Anybody know what is on some new pots that causes the trouble?

[Joe Gwinn]

I understand but there is something on some brands of modern pots that will not accept solder very easily if at all. I can solder to the bodies of most old pots just fine. Even without redorting to the big iron that I use to solder to chassis. But even the big one will not allow me to solder to some modern pot bodies without sanding them. Anybody know what is on some new pots that causes the trouble?

The old pots were tinned or plain mild steel. Are some o0f the new ones aluminum? That would make it pretty hard to solder. What does work is to form a puddle of liquid solder on the metal, and then scrub the surface with a stainless steel brush right through the solder. This works even on aluminum. For steel, the equivalent is to scrub the steel surface with the soldering iron tip, but the tip probably isn't aggressive enough for aluminum. But it's probably too much trouble, so it may be better to use the big solder terminal, as David suggests.

[Spence]

It's probably some sort of lacquer that's causing the problem.

[David Schwab]

Some parts seem to be plated with something... like the chrome looking plating on some jacks. That stuff never holds solder without scraping to the bare metal, which often looks like a brass alloy.