Tech: Soldering guitar cables

Subject: RE: Tech: Soldering guitar cables
From: GUEST,Slickerbill
Date: 19 Nov 02 - 12:30 PM

Great help folks. Thanks very much. sb

Subject: RE: Tech: Soldering guitar cables
From: JohnInKansas
Date: 16 Nov 02 - 11:38 PM

Joe - Sorry to take so long. I wrote this up at about 04:30, but the 'cat wouldn't answer to let me post. Started a defrag - and it ended up at about 18 hours.

A brittle joint is usually due to too much heat, or a cold joint due to motion while the solder is cooling. It doesn't take much to get a copper wire hot enough to oxidize, and if you have a good flux, the oxide breaks up and mixes with the solder. Two bad things - the wire gets smaller, and the oxide makes the solder kind of like a wad of snot.

If you don't have the right "heat," you don't get the solder to "flow" into the joint on its own, and the tendency is to try to "push some more solder in," which makes it harder to get a good flow - and can also cause you to overheat the wire, insulation, plug, and sometimes fingers.

A soldering iron that's "just right" for a circuit board repair may be a little small to bring a cable wire up to temperature - because the wire "sucks" a lot of heat out of the joint area. On the other hand, too large an iron may get the joint so hot that it "burns" faster than the flux can work. Overheating the joint, while you're trying to "work it in" can also burn the tin out of the solder - making your good 60/40 low melting point stuff that you started with into something more like an 80/20 - that's like trying to melt cast iron. (a little exaggeration is permissible?).

If the contacts and wire are clean, and they're wrapped or crimped together so that everything comes up to temperature together, and if your iron (or gun) tip is tinned clean so that it makes good contact to transfer the heat, you should be able to press the iron against one spot, hold it there for two or three seconds, and then touch the solder to the joint and let it "flow" itself into the joint.

You only need enough solder to "wet" the joint, if you get it to flow in. Solder holds only by surface tension. More solder doesn't help - and usually will actually weaken the joint.

The right size soldering iron depends a lot on your technique. I've known some guys (experienced lab techs) who could assemble a brass auto radiator with a 15 Watt pencil. For most people of ordinary technique, a 35W or 47W would probably work on reasonably sized stranded wire, although if you've got one of those fancy "electronically controlled" irons a little smaller one may work.

A "clean" tip on the iron is important, and it's normal practice to "tin" the tip. The "liquid" tinned surface helps the heat transfer. Once you've scraped the tip clean (a fine-toothed file works well if it's rough - a wire brush if it's not too bad to start) you need to bring the tip up to temp and touch enough solder on it to coat it. (I'm assuming a flux-core solder. Flux before tin if not.) Excess solder here doesn't hurt, because just before you touch the tip to the joint, you wipe it across a damp (not soggy) sponge to take the excess off - so that the first contact with the joint is "fresh solder."

If the solder doesn't "suck in" within a couple of seconds (5 or 10 at the max) you probably need to make a better twist (better contact between parts of the joint), get a little bit bigger iron, and/or or use a smaller diameter solder wire. Once it "sucks," hold the iron on for just a couple of seconds, and then pull it off - but don't allow the joint to move until the whole surface "frosts" to indicate that the solder isn't liquid any longer. And resist the temptation to "push in a little more solder" once the joint "wets." More is not better.

One of the problems you'll run into is that a lot of "modern" cable isn't really "made to solder." The wire drawing lube frequently is left on, and additional or other lube may be added to make the cable more flexible. At the factory, they can "etch" clean, and probably use crimp (or spot welded) joints exclusively, before they vulcanize the whole thing.

"Tinning" both sides of the joint before you connect them will let you see if there's a problem, and will help once you're ready to make the joint. If the wire acts like it doesn't want to tin, then a little alcohol rinse (or ether if you're real brave and foolish?) may take the lubes off - let it drip off, to take the grease away, and air dry thoroughly, since wiping may just move more grease back. I've seen cases where there was so much lube left in a cable that sandpaper just pushed the grease around - you have to analyze each joint, I guess.

Clean - Clean - Clean.
Tin first, with a very thin application of solder
Just the right amount of heat.
Just enough solder (with a good flux).
Just the right (minimum) amount of heat to sweat it in.
And absolutely NO motion until its hard.

And of course - advice is easier to give than to use. That's why I mostly try to use crimp terminals when I can. (The bare ones can be "tinned" after they're crimped - if you're a belt and suspenders type.)

John

Subject: RE: Tech: Soldering guitar cables
From: Joe Offer
Date: 16 Nov 02 - 02:46 AM

It seems that whenever I solder onto a plug, the wire gets brittle and the junction rigid, and my solder job seems to break after a fairly short time. Any idea what I'm doing wrong?
-Joe Offer-

Subject: RE: Tech: Soldering guitar cables
From: JohnInKansas
Date: 16 Nov 02 - 01:34 AM

Yet another: Since the question was about soldering, the simplest thing to discuss is "soldering a wire" - whether to another wire or to a terminal, the principle's the same.

You can get jackplugs with screw terminals and/or with solder terminals. If you're using the screw, it's still a good idea to "tin" the strands before you screw them down, and most of the "old hands" I've known consider it best to throw the screw away and solder them - regardless. IF you can find a decent crimp-on ring terminal small enough, I'd personally go that way, with the screw, but good ones small enough to go in a jack are hard to find.

The principal that the wire needs to be as clean as you can get it is the "governing" one, since the jack terminals usually are fairly clean. The individual wire strands are often "drawn" with a lube that has "always been there," and it can be pretty tough to get it off to the point that the solder will wet the joint, especially on an old cable.

The "twist them together" also applies: you should always try to "wrap" the wire "into or around" the terminal (or the mating wire) so that it will hold itself in place before you apply the solder - since otherwise it's almost impossible to avoid some movement while the solder is cooling, which will cause a cold (high resistance) joint.

Most cable breaks are at, or very near the terminals, so if you can figure out a magic way to decide which end is bad, you can usually make a 19.5 footer out of a 20 - or a 19 if you guess wrong when you cut the first jack off (assuming molded-on "factory" cables).

To first Guest - no, it won't stay in tune unless you've got a glass (or better, steel) bodied guitar. And the best solution for Spaw might be that "foam-in-place" insulation stuff, squirted into the soundhole till it bubbles up over the strings. Won't keep it in tune, but makes some of them sound a lot better. (And those plastic wire ties make good spoon capos too, as long as you get them tight around both spoons.)

John

Subject: RE: Tech: Soldering guitar cables
From: GUEST,Yet another guest
Date: 15 Nov 02 - 08:33 PM

Another guest,

Superglue would be better for the task you suggested.

Much of this thread seems devoted to the task of joining wires together but the original post says: "slice these up to see if I can get em working again, make two 10's out of a 20, that kind of thing".

I may not be reading correctly but my interpretation is that the originator is looking to fit jack plugs rather than join wires.

Subject: RE: Tech: Soldering guitar cables
From: GUEST,Another guest
Date: 15 Nov 02 - 08:00 PM

No, guest. But if you are serious I would suggest soldering your hands together.

Subject: RE: Tech: Soldering guitar cables
From: catspaw49
Date: 15 Nov 02 - 07:50 PM

It's been suggested that I would sound better if I soldered the strings together........

Spaw

Subject: RE: Tech: Soldering guitar cables
From: GUEST
Date: 15 Nov 02 - 07:21 PM

I have a question. Do you think my guitar would STAY in tune if I soldered the tuners after tuning the strings?

Subject: RE: Tech: Soldering guitar cables
From: catspaw49
Date: 15 Nov 02 - 06:51 PM

The only thing I'd add here is to "tin" the wires first. That is to apply a coat of solder (use higher quality as John said) after you clean and flux them...Then carefully wrap the two. Heating the joint now will probably require no more solder and provide a better joint, much cleaner looking too! This is even more important when you solder multiple strand wire but it is always the best way to go.

Spaw

Subject: RE: Tech: Soldering guitar cables
From: JohnInKansas
Date: 15 Nov 02 - 06:00 PM

Radio Shack - if you find one that's reasonably stocked - has a good selection of heat sink clamps, clips, "third-hand" vises and such that work quite well, although they're mainly intended for circuit board work. Something heavier works better on cables. I've used a pair of slip-joint pliers with a rubber band on the handles when I needed something with a little more "sink" to it.

Anyone with a strong enough resistance to "might-need-its" might benefit from a visit to a well stocked Sh*tShack before getting started, since they usually have a fair selection of splices, connectors, crimpers, etc - that might give you a better way. You might also find one of their "how to" guides to soldering.

The real problem is that, as independently owned franchise stores, individual ones often stock only what the operator is interested in. You have to look for the good one in your area.

John

Subject: RE: Tech: Soldering guitar cables
From: GUEST,Q
Date: 15 Nov 02 - 05:18 PM

Somewhere I found some spring metal clips. They work as small heat sinks.

Subject: RE: Tech: Soldering guitar cables
From: JohnInKansas
Date: 15 Nov 02 - 04:59 PM

A small caution - While you can get "electrical" solder at the local lumber yard, the stuff that comes in big spools is usually intended for soldering house wiring and such. It is likely to be a 70/30 or worse, and may have a "core" of pretty low-grade "resin" flux.

For soldering "electronic" stuff - like cables, you want to be sure that you get a true 60/40 solder with "electronic" grade flux core - or solid wire with some good brush-on flux that you can apply separately.

Be sure you do your soldering in a reasonably well ventilated area, especially if you're using normal 60/40 tin-lead solder. The fumes should be minor, but there is always some lead (and flux) smoke.

There are also "lead free" solders on the market now, but I haven't tried them.

Especially on stuff like shielded cables, there are times when solder is the way to do it, but if you look around you can probably find crimp-on connectors for almost any kind of connection you need. They're the "modern way," and if properly crimped are generally much more durable and reliable than a soldered joint.

A common "error" when working with shielded cable is "cutting the shield" down to a few wires. If you strip the insulation off the outside of the braided shield, and push it back so that the braid "opens" a little, you can use any "small pointy tool" to open a hole through the side of the braid - about a half-inch back from the end, and pull the center wire(s) through the hole. Then when you pull on the (now empty) braid, it collapses down to a "wire" that you can "tin" and solder, without loosing pieces of wire from the braid (and without having a lot of "little pointies" sticking out of the solder.)

As Guest Q said, the critical thing is to get the wire clean enough (and use an appropriate flux) so that the solder "wets" the wire when it melts, get the solder melted fully, and I would add, once you remove the heat - don't move anything until its fully cooled. Clamps help sometimes.

With some cable, it's almost impossible to get the wire hot enough to solder without "melting" the insulation for a ways back from the joint. A clothespin (spring type) on the insulation near the joint can help keep it from overheating - if you encounter that problem.

If you're splicing in the middle of a cable, be sure that you tape it enough (or put a short "shrink-tube" on) so that the cable is a little "stiffer" around the joint than the rest of the cable. It'll last a lot longer if the solder joint isn't flexed.

John

Subject: RE: Tech: Soldering guitar cables
From: Jacob B
Date: 15 Nov 02 - 04:58 PM

Let me tell you what NOT to do, so you can avoid it.

DO NOT melt the solder with the soldering iron and drip it onto the wire. This is called a cold solder joint. It will hold the wires together, but it won't conduct electricity.

I disagree with Guest Q's advice to "Apply the solder wire end to the area to be joined, and the hot iron tip to that same point." My advice is to hold the solder to the top of the joint, and bring the soldering iron to the bottom of the joint. You want the hot wire to melt the solder, not the soldering iron.

Since you're just soldering cables, you don't need to worry about excessive heat ruining delicate electronic components. If you get ambitious and want to solder electronic components, come back and ask about heat sinks first.

Good luck.

Subject: RE: Tech: Soldering guitar cables
From: GUEST,Q
Date: 15 Nov 02 - 03:19 PM

General- Expose and clean the ends to be joined for 1/2 to 1 inch with fine sandpaper. You need a small soldering iron and electrical or silver solder wire. Twine the two ends together. Do not break the fine, individual wires. With one hand Apply the solder wire end to the area to be joined, and the hot iron tip to that same point with the other hand. When the solder liquifies, dress the twined wires with the solder as neatly as possible. moving the iron up and down and on all sides of the joined wires. W.when the join cools, wrap with electrical tape.
May take a little practice. Try it with scrap multistrand wire of about the same gauge first.
A more technical treatment is here: Soldering

If this link doesn't work, put "soldering wire" in Google. It was the first item. Acrobat needed.
www.mil.ufl.edu/4744/labs/lab2_f02.pdf

Subject: RE: Tech: Soldering guitar cables
From: Bert
Date: 15 Nov 02 - 03:03 PM

There are two rules of soldering.

Get it clean
and Get it hot.

Subject: Tech: Soldering guitar cables
From: GUEST,Slickerbill
Date: 15 Nov 02 - 02:27 PM

I've had a couple of cables go bad on me recently, and thought this might be a good time to acquire some soldering skills; you know, slice these up to see if I can get em working again, make two 10's out of a 20, that kind of thing. Any instruction out there on the do's, don'ts and how-to's of cable soldering? Web sites on the subject are very welcome.   sb