stranded wire vs solder wire?

[ashton8504]

bought a bunch of pedal parts etc. I am a noob and wondering which is better stranded wire or solder wire?

[EATyourGuitar]

You mean to say stranded or solid. Some people like things that look old. Solid cloth wire is one example of vintage correct wire. There may be functional uses for a stiff wire if it holds the pcb in place. All things being equal for the same mass per foot of copper, stranded has more surface area so it may be very slightly better but not by much and not at such low voltages.

[ashton8504]

whats the best wire to get used to?

[EATyourGuitar]

I prefer smallbear pre-bonded silver #24 stranded

[thelonious]

It kind of depends on your preferences or needs in a given situation. Solid wire stays where you bend it and is easier to fit through teeny PCB holes, IMO. Stranded is flexible. I tend to prefer solid because with stranded there's inevitably that one strand that won't go through the hole...

[ashton8504]

does solid wire coming in different colors?

[thelonious]

Sure, you can get either stranded or solid in all kinds of colors. Also, the pre-bonded stranded that EATyourGuitar mentioned sounds like the best of both worlds - flexible, but bonded so you won't have stray strands. http://www.smallbearelec.com/servlet/Detail?no=903

[tyzjames]

I have used solid for a long time but after a while i realised that it has reliability issues. The wire seem to be able to detach itself more easily over time. I like to it holds its position though. I now use standard 22awg teflon wire. Feels very very solid, but bad thing is that its flexible.

[EATyourGuitar]

I have used solid for a long time but after a while i realised that it has reliability issues. The wire seem to be able to detach itself more easily over time. I like to it holds its position though. I now use standard 22awg teflon wire. Feels very very solid, but bad thing is that its flexible.

teflon jacket is great if you are trying to spend some money. it takes a lot more heat to melt the teflon jacket. it is closer to being milspec than standard PVC jacket. it also resists some chemicals better than PVC but thats more for industrial, medical, military etc... we don't spray chemicals on the wires daily so it is not like that is even a concern.

[Kesh]

i dislike solid as it is easy to weaken it while stripping it, meaning it later breaks. It's also more fiddly to solder.

I wish you could get prebonded in UK.

[Thecomedian]

I dont recall if it's factual or not, but electrical current prefers to travel on the outside of wire, so stranded wire, with it's many individual roads, can pass more current. It's why you go up (or is it down?) a gauge or two (thicker wire) if it's the same circuit with the voltages and current.

Solid wire can be better for staying in place, as long as care is taken not to weaken it with excessive bending. If it was completely exposed copper wire, you could theoretically anneal it again. Solid wire gets stiffer when bent because the rows of perfectly aligned atoms are getting smashed together, creating a stiffer, but also more brittle, section of wire.

when stripping, it's possible to nick the wire, creating a weak spot. if it's stranded, you'll just lose a strand or two.

in a vibration heavy environment, stranded wire holds up better over time. How much so depends on all the obvious factors. Is it a free floating wire connecting to separate areas, or is it a tiny wire that connects to two spots on a single device, like pcb, vero, or switch (for instance). I'd say always use stranded when you are leading from the circuit board to the switches and pots. On board, you can go nuts with solid if you like. It also makes things cleaner and easier to work with. do NOT try to support a board using the inherent rigidity of solid core wire. Recipe for disaster, or at least headaches soon down the road. If the board and/or pedal has some vibration absorption parts (pad, spring, etc), then solid wire and GOOD solder technique should last longer than you, provided you don't throw the thing in a garbage disposal or down some stairs.

For working around the fiddliness of tinning copper wire, hold the iron under the wire's exposed end, and place the rosin-core solder above the wire. Since heat rises and liquids are pulled down by gravity, easy tinning achieved. Add flux paste where needed for solder without any inside it.

[Mark Hammer]

If you are making something for the umpteenth time, and know exactly how long each wire has to be and where it has to go, you can opt for the sturdiness, neatness, and predictability of solid core.  If you make one pedal for yourself, and maybe a second one for a buddy, you'll want the flexibility, twistability, and bendability, of stranded.

I'm a big fan of the Smallbear pre-bonded stuff.  Strip it and it still slides neatly through the hole.  Tins more readily than solid core too.

[Thecomedian]

If you are making something for the umpteenth time, and know exactly how long each wire has to be and where it has to go, you can opt for the sturdiness, neatness, and predictability of solid core.  If you make one pedal for yourself, and maybe a second one for a buddy, you'll want the flexibility, twistability, and bendability, of stranded.

I'm a big fan of the Smallbear pre-bonded stuff.  Strip it and it still slides neatly through the hole.  Tins more readily than solid core too.

When using stranded, just strip, twist the end a little so there are no stray wires, and tin it. Tinning will bind them all together when done right...

[reverberation66]

I hope what you get from this is it doesn't matter too much either way...they both work fine, it's really just a matter of personal preference. 

[Tony Forestiere]

I am going to weigh in with a stupid "aside" note.  For breadboarding, (as opposed to PCB population), solid core is the way to go. You don't want to be cramming strands into your breadboard contacts.
Carry on.

[Jdansti]

Just take 5 strands of solid, strip off all of the insulation, braid them together and put heat shrink on them. That way you get the benefits of solid and stranded.  

Edit: I apologize. The other John that lives in my head hacked my DIYSB account and posted the stupid suggestion above. Please disregard.

[R.G.]

I dont recall if it's factual or not, but electrical current prefers to travel on the outside of wire, so stranded wire, with it's many individual roads, can pass more current. It's why you go up (or is it down?) a gauge or two (thicker wire) if it's the same circuit with the voltages and current.

You're referring to the "skin effect". As the frequency of electrical current increases, electric and magnetic field interactions force the current progressively toward the outside of a wire. This bit of fact is used by huxters to sell you very expensive wires with many strands. At DC, there is no difference between a single wire and the same cross sectional area of however many finer strands added together. At radio frequencies, the current may travel only on the outside surface. However, within the almost-DC frequencies of the audio band, skin effect is not a consideration for wires any of us are likely to use. The skin effect is simply too small at audio frequencies to matter much.

As Alexander Pope wrote:

A little learning is a dangerous thing;
drink deep, or taste not the Pierian spring:
there shallow draughts intoxicate the brain,
and drinking largely sobers us again.

when stripping, it's possible to nick the wire, creating a weak spot. if it's stranded, you'll just lose a strand or two.

Nicking wire when stripping is a Big Deal. Solid breaks faster, but the concentration of stress where fewer strands join more strands also forces flex-hardening to locate there, as well. The real answer is to not nick the wire. Thermal stripping is the only easy way to avoid this.

[PRR]

> current prefers to travel on the outside of wire

HIGH frequency current, true.

For reasonable wire sizes (like in a pedal) this effect matters above 100KHz.

And only if resistance is significant. You can't put enough wire in a pedal to make enough resistance to matter.

Stranded wire has almost no effect on skin effect.

Skin effect in 455KHz-1MHz radio coils that older radios used Litz Wire for maximum selectivity. But that is expensive. And interestingly, above 10MHz there is no advantage, and the usual approach is a larger gauge (even tubing for high-power work).

Anyway: pedal-wire is "never" picked for its resistance. The "minimum size" for most of this stuff is hair-strand or smaller.

Fat fingers and bad roads are why we use gauges in the 20s instead of 40.

> you go up (or is it down?) a gauge or two (thicker wire) if it's the same circuit with the voltages and current.

No. Or I've never seen that.

Common wire is specified as if it were solid. The same gauge of stranded will be a little bit larger overall due to the inter-strand gaps. Both are rated for the same current (the surface area increase does not improve heat dissipation enough to matter). Wire is stranded mostly when solid wire would be too stiff. In small boxes on bad roads, stranded may handle the vibration better. In large power systems, stranded can be bent by hand or simple tools, bending the 1/4" stuff in my meter would require jigs and levers if solid.

And of course, for all sane voltages, conductor diameter has nothing to do with voltage. (Yes, above 10,000V corona favors larger diameter, but also elaborate tapered insulation, which is another reason we don't use 10,000V in pedals.)

[Jdansti]

I did this as an exercise to see if it would be feasible to make a DIY thermal insulation stripper. It uses 3in. of 40ga nichrome C wire looped around two screws as a heater. The idea is for the wire wedge shown below to come together close enough at one side to slide the wire toward the smaller diameter screw and melt through the insulation.



40 ga NiCr-C wire can be found all over the Internet for about $2.25/10ft. 

Other NiCr gauges and supply voltages can be used if you make the appropriate change to R1.  For example:

3 in. 40 ga/9V (500mA rating)>>> R1 = 18R/2W+
3 in. 32 ga/9V (1A rating)>>> R1 = 10R/7W+

See http://hotwirefoamcutterinfo.com/_NiChromeData.html for NiCr resistance and heating data.

I think this should work, but please let me know if anyone sees any fatal flaws.

[Thecomedian]

which is why Im glad there are people who can bring the facts out. I wasn't aware that the skin effect was only extremely high frequencies.