Connecting wire to boards

[matmosphere]

Noob problem here. I've built about ten pedals now, but the weak point in my builds seem to be connecting wires to the circuit board. I've been building on veroboard using 22AWG stranded wire. I generally put a twist in the wire after i strip it, but have been wondering if it is better to avoid twisting it. I've also considered using solid wire, it would be easier to solder, but am worried that it might not be durable enough.

[tombaker]

I use stranded sometimes and twist after stripping, also tin them before you solder them in, that way you won't overheat the wire.
But what is your actual problem? That the wires don't connect or are noisey?
I'm not trying to sound rude, even if it read that way.

There was a thread a while back about stranded vs solid core wiring, if you use the search tool that'll give you some light reading re: the pros and cons

[greaser_au]

Molex-style connectors (a la Steve's Bare Box concept), or pins interference fitted (snale) or swaged (turret) into the board really are the *ultimate* in flyinglead-to-board connection.    Even Boss use an eyelet/rivet to solder to.

Do you find wires break off?   if so, design your PCB/vero so that you can have a suitable hole (sized to suit the insulation size) somewhere near the wire hole. Thread the wire end from the solder side and insert the stripped/tinned end where it needs to go.  Better still, add 3 rows/columns  at the 'pot end' of the vero and thread ALL the wires out here (even if you do not design with all wires terminated on one edge).  

DEFINITELY strip, twist (preferably at the same rate and direction it already has)  & tin stranded wires. if you're boxing it up forever and everything is well secured, solid wires are fine. if you are likely to be doing repetitive work like mods or there will be any flexing or movement, stick to stranded (there is a reason for stranded wire to exist - for a perfect example look at a 9V battery snap ).

david

[matmosphere]

Awesome, thanks guys. I wasn't tinning the wires. It makes a lot of sense and I suspect it will help a lot.

tombaker (nice by the way, what do you think of Capaldi?) i put one of my projects in a new box recently and had a lot of the pot wires break at the board. Probably will need to replace them all.

David are you suggesting leaving the extra room so that the wholes can be enlarged and wire threaded through and then stripped and back through to the solder side to be connected? It does seem like it would be very secure. Those Molex connectors look like they would be very nice to work with. Can the wires be over twisted?

[KazooMan]

The comment about threading the wire through a second hole is a good one.  It really takes all of the potential strain off the connection.

I suspect that you are nicking the wire when you strip it.  It is hard not to when using simple pliers style strippers.  The nicked portion ends up right at board level where the flexing occurs and it provides a start for the wire to eventually fail.  The best solution for this is to use a thermal wire stripper.  They work great and will not nick the wire, but they are not cheap. 

[karbomusic]

The only time I've ever had a problem is what I might call extreme and excessive handling after soldering. As in troubleshooting or modifying for hours. When I do that, which is rare, I consider it good practice to redo them anyway. However, the normal wire it up and make a few changes here and there has never caused me a problem at all so I'm interested in how it happens for you. I never run them through a second hole, never had to.

[greaser_au]

David are you suggesting leaving the extra room so that the wholes can be enlarged and wire threaded through and then stripped and back through to the solder side to be connected? It does seem like it would be very secure.

yes, exactly. if you are experiencing breakage, this will take the strain off the soldered ends. Like anti-static precautions,  people say they've never had to do thngs like this, but everybody (and their environment or skillset) is different - horses for courses and all that. This is only a suggestion,  you might give it a try & see if it helps. If not - no biggy!

Can the wires be over twisted?

Definitely. if you take an offcut of the stranded wire you are using and strip 10-15mm, you will see it has a natural 'lay'. Look down the end of the stripped piece of insulation and you will see  the 'rifling' - cut it lengthwise if you need to, you will be able to see the twist rate.  Make sure you maintain the direction of the twist, and try to maintain something near the twist rate (or a little more maybe - not important, just don't overdo it)  before tinning.

Here is me both using and breaking my own rules!!!  0.1" pins and connectors. wires straight into the board (the big black loom of shielded cables are tied down with 24g solid wire (after the photo). I've glued similar constructions down with epoxy more than once.

david

[matmosphere]

Thanks all.

Kazooman, I am actually using automatic wire strippers. They work well but unfortunately strip more length than I would like.

With my earlier projects there was definitely a lot of troubleshooting and adjustments made. That is probably the source of most of these problems. I was just wondering if there was a better way. I figured if it couldn't handle the troubleshooting process it might not hold up well over time.

[vigilante397]

 Better still, add 3 rows/columns  at the 'pot end' of the vero and thread ALL the wires out here

I don't know why I've never thought of this. Brilliant suggestion. I use solid core and while I don't move the wires enough to make them snap often it still is a concern of mine. I will definitely try this out. Seems like it would make soldering a lot easier as well as you don't have to worry about the wires flying about.

[KazooMan]

Thanks all.

Kazooman, I am actually using automatic wire strippers. They work well but unfortunately strip more length than I would like.

Automatic wire strippers!  That's above my pay grade!  I assume that there is some sort of depth adjustment on your gear.  I would still recommend having a really close look to see if the stripper is nicking the wire. 

[PRR]

> Automatic wire strippers!

There are "auto strippers" for any pay grade.

I once got three for 5 bucks here: Ecdysiast.

But AmSciPlus is out-o-stock. Here's another low-price www.galco.com/buy/Michigan-Industrial-Tool/3792

Quality varies a LOT. I wonder if this may be part of matmosphere's struggle?

Finding wire-strippers you like can be a life-time hunt. Moreso because what works for small wire or soft plastic may fail on large or tough plastic. I have a drawer-full that I turn to for different jobs.

One that does NOT! nick the strands is the thermal wire stripper. Some are modified soldering irons, and a bit likely to burn you. I like the PATCO: http://patcoinc.net/PTS-10.html , however it IS extravagant for a few pedals.

[CodeMonk]

I've been using these since the 80's:


They are (or were in the 80's, dunno how popular they still are, along with thermal strippers) widely used in the electronics industry.
Kind of expensive though:
http://www.amazon.com/12-21-180-SB-Automatic/dp/B005EXNX0M
Although they can be had for less : http://www.amazon.com/gp/product/B00BC39YFQ/ref=pd_lpo_sbs_dp_ss_1?pf_rd_p=1944687442&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B005EXNX0M&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=0BPK3KF9BAYGSY3GNVY6

I've been using the same pair for 25+ years.


Same model as mine:
http://www.amazon.com/Ideal-Industries-Stripmaster-Wire-Stripper/dp/B000RFSWF8/ref=pd_sim_indust_1?ie=UTF8&refRID=10FY8R5FPBW4S75BYPBH

[PRR]

> I've been using these...

Those can be excellent (or not).

However I'd call them "one handed" strippers. You still have to get the wire in the notch, the right notch.

The type I linked to, you do not have to know what size your wire is, or hit a notch. The jaw is a half inch wide, get the wire anywhere in there. When you squeeze, a ribbed area grips the plastic and a sharp blade bites the plastic. When the bite-force increases (as when you hit copper) a slip toggle changes your squeeze from biting to yanking the grip-blade apart.

If it likes your wire, it is bl**dy amazing how it strips without fuss.

If it don't like your wire it just scrapes it, or cuts it off, or chews the end to a pulp.

I will usually use a notched stripper or a very sharp blade (PATCO is best for extended bench sessions). But working overhead in the tractor, the one-hand no-notch features can be very compelling.

[CodeMonk]

> I've been using these...

Those can be excellent (or not).

However I'd call them "one handed" strippers. You still have to get the wire in the notch, the right notch.

The type I linked to, you do not have to know what size your wire is, or hit a notch. The jaw is a half inch wide, get the wire anywhere in there. When you squeeze, a ribbed area grips the plastic and a sharp blade bites the plastic. When the bite-force increases (as when you hit copper) a slip toggle changes your squeeze from biting to yanking the grip-blade apart.

If it likes your wire, it is bl**dy amazing how it strips without fuss.

If it don't like your wire it just scrapes it, or cuts it off, or chews the end to a pulp.

I will usually use a notched stripper or a very sharp blade (PATCO is best for extended bench sessions). But working overhead in the tractor, the one-hand no-notch features can be very compelling.

I guess its just what I am most comfortable with.
My first job in the electronics industry was at Litton Data Systems and those are the ones I used.
And at most of the other jobs I had as well.
Southern California, a lot of Military and Aerospace, spending $100+ for a pair of wire strippers was like a drop of water in them ocean to them.
The nice thing about these are that as it pulls the insulation off, it doesn't disturb the twist in the wire.
I got mine for free though. Company I worked for moved into a smaller building, auctioned off the excess furniture and such including "surprise boxes".
No one knew what was in any of the boxes. I just bid on the right box (Ok, I'm guilty, I was also the one that packed all the boxes   (Hey I was 24 and never claimed to be an angel in my youth))


> You still have to get the wire in the notch, the right notch.
True.
You know how it is sometimes, after so many years you sometimes forget how awkward something may be to someone that has never done it before.

[amptramp]

I have used AWG30 wire-wrap wire for off board connections.  It is solid conductor (not stranded) and fairly flexible and it has minimal capacitance to anything else.  There are cheap strippers for it and the kynar insulation is resistant to abrasion, something you won't find with Teflon insulation.  When I worked on spacecraft and avionics, Teflon wire was the norm inside the box and thermal strippers were used.  They never nicked the wire.  But in the airframe, we used more abrasion-resistant and cold-creep resistant wire because you could not bend a Teflon wire around a sharp edge without it cutting through eventually.