Is anyone still using wire wrap for prototypes?

[e100]

Everything that I build is a one-off design that starts life on a breadboard and when that gets too frustrating because of unreliable connections I pull everything off and do a point to point soldered construction on a protoboard which unfortunately takes 20x as long and is a pain to modify.

I see lots of hobbyists doing PCBs but I really cannot justify the time cost of laying out a board that will take a week or three to come back and will most likely require multiple bodge wires.
Various documentation talks about gas tight connections and reliability. How do these perform in the real world outside of humidity and temperature controlled environments?
Can a post be rewrapped or does the wrapping process flatten the edges making subsequent wraps less reliable? 
Once a design has shown to work reliably do you go back and solder the connections or give it a coat of PCB lacquer or is that unnecessary?

Mike

[Kappes Buur]

That certainly brings back menories.
Wirewrapping is still a viable option, but it takes the right tool and feel to have a
good result. The best tool is a powered wrapping tool, when used with the correct
bit for the wire gauge. A manual hand tool is for unwrapping a bad connection.

Rewrapping is not a problem since it is the wire which gets deformed and not the post.
Over on Nuts and Volts is a good article abouit the subject:
http://www.nutsvolts.com/magazine/article/wire_wrap_is_alive_and_well

[ataradov]

Components ready for wire wrapping are not manufactured for at least 20 years, what are you prototyping there?

Properly done wire wrapped connection is more reliable than a soldered one, no need for additional solder or conformal coating (unless you are really working in a harsh environments).

I'd say, figure out how to be more efficient with protoboards, it will be better in a long run.

[rob77]

I see lots of hobbyists doing PCBs but I really cannot justify the time cost of laying out a board that will take a week or three to come back and will most likely require multiple bodge wires.

and that's why i'm making my boards at home. 2 layer with soldermask and riveted vias in 1 hour if you work fast then 30 minutes. raw materials are cheap, so spinning a board 2-3 times to fix issues is not a problem... basically the time spent on making the PCBs is far less than troubleshooting "nonexistent problems" coming from breadboarding or hours spent on vero/proto-board prototype construction.

[e100]

I see lots of hobbyists doing PCBs but I really cannot justify the time cost of laying out a board that will take a week or three to come back and will most likely require multiple bodge wires.

and that's why i'm making my boards at home. 2 layer with soldermask and riveted vias in 1 hour if you work fast then 30 minutes. raw materials are cheap, so spinning a board 2-3 times to fix issues is not a problem... basically the time spent on making the PCBs is far less than troubleshooting "nonexistent problems" coming from breadboarding or hours spent on vero/proto-board prototype construction.

Do you drill the holes by hand, using a drill press or CNC?
In my experience this is the least fun part of the process, 0.5mm error here and there and it soon ends up looking like a mess.

[e100]

Components ready for wire wrapping are not manufactured for at least 20 years, what are you prototyping there?

Typical collection of DIP op amps, axial resistors, LEDs, Micros with 0.1" headers. Nothing surface mount.
Wire wrap DIP sockets are still available, so I'll be using carrier boards like this http://www.nutsvolts.com/uploads/wygwam/NV_1201_Schumaker_Figure11.jpg

[ataradov]

Wire wrap DIP sockets are still available, so I'll be using carrier boards like this

While sockets are available (for some really mysterious reason), where will you get those carrier things?

Also, wire wrapping requires skill and time to prepare wires. I doubt it is faster than doing things on a protoboard, unless you spend a lot of time training. You might as well train soldering, because it does not take all that much time, if you do it right.

[kripton2035]

I almost stopped doing pcb at home because of the time it takes to lay down the pcb layout.
It's ok if you have 10 pcb to do, but not for one. You've better make a protoboard, it will use the same amount of time to think of the layout and do it.
then if you have 10 pcb to do, use a pcb fab house will be easier than do yourself 10 times the same (boring) board.
protoboard and small smd pcb adapters are the way to go.

[e100]

Wire wrap DIP sockets are still available, so I'll be using carrier boards like this

While sockets are available (for some really mysterious reason), where will you get those carrier things?

Also, wire wrapping requires skill and time to prepare wires. I doubt it is faster than doing things on a protoboard, unless you spend a lot of time training. You might as well train soldering, because it does not take all that much time, if you do it right.

Turned pin dip sockets are still available. You can solder directly to the top.

[ataradov]

Turned pin dip sockets are still available. You can solder directly to the top.

How is this different to soldering things to a protoboard? Remember, you will also need to fix this sub-assembly to the board before wiring. And wires for wire wrapping need to be stripped to a very specific length and then wrapped. I don't see how this is faster than stripping the same length of wire for soldering and applying solder.

[e100]

That certainly brings back menories.
Wirewrapping is still a viable option, but it takes the right tool and feel to have a
good result. The best tool is a powered wrapping tool, when used with the correct
bit for the wire gauge. A manual hand tool is for unwrapping a bad connection.

When wrapping, if there any difference in the quality of the connection when using an electric, hand powered trigger, or twist with the fingers type?
Does the electric type provide more consistent torque control?

[e100]

Turned pin dip sockets are still available. You can solder directly to the top.

How is this different to soldering things to a protoboard? Remember, you will also need to fix this sub-assembly to the board before wiring. And wires for wire wrapping need to be stripped to a very specific length and then wrapped. I don't see how this is faster than stripping the same length of wire for soldering and applying solder.

Have you used wire wrapping for any of your projects?

[ataradov]

No,  I'm not crazy.  I used to recycle electronics for extra cash,  and some of it was wire wrapped,  so I had to remove that to get better prices on recycled metals.  I tried to play with actual wiring at a time,  since technology was somewhat interesting.

[SeanB]

You get better torque control with the power tool, and a consistent tension in each turn with less training. However the hand tool can do the same job, albiet slower, with practise.

You also get wire wrap wire spools that are no strip, the act of wrapping it around the post displaces the insulation and the metal to metal contact is protected as well by the insulation from corrosion.

[Kjelt]

I use wirewrap teflon wire for my one or two off proto boards but do not use wirewrap components.
I use regular components strip the wirewrap wire put it in the "hole" next to the components pin and then turn it twice around the pin and then solder the connection.
I was always taught that a good soldering connection starts with a solid mechanical connection.
My prototypes from the 80s and 90s still work today although some connections could use a resoldering.
BTW if you do it like this make sure you have enough colours and use them wisely, for instance black for ground and red or purple for Vcc etc. Do not use only a single colour as those pro wirewrappers did in the old days wrapping computer backpanels which makes  it a nightmare to figure out after a few years 

[jonovid]

i have more than one breadboard. so you can have lots of circuits / projects made up at one time.
when i know circuit works the way I like it to. it goes on to perfboard .
Wire wrap is a way to hold wires before adding solder.
I have seen an 1980s audio amp  with lots of Wire wrap inside it, I wonder if it had any dry joints. 
only the most serious of projects get the full PCB works.

[Gyro]

One of the wiremen in our lab (that takes you back  ) taught me to operate one of the Vero 'cut strip and wrap' guns. More difficult to master than the ordinary ones where you stripped a length and poked it up the hole in the end of the tool, but SO much faster when you did. The wire was channelled through a hook up the outside of the bit and it did the whole thing in one operation, automatically leaving the 1 1/2 turns unstripped at the bottom for vibration relief (critical for reliability) and always wrapping the correct length. It also had a rotating cutter near the top of the shaft and depending whether you routed the wire through this or not, it would either do single runs or daisychain connections. A magic tool, I used to borrow one at the weekends on threat of death if I broke it or forgot to return in on Monday morning. It was the fastest prototyping method you ever saw.

[rob77]

I see lots of hobbyists doing PCBs but I really cannot justify the time cost of laying out a board that will take a week or three to come back and will most likely require multiple bodge wires.

and that's why i'm making my boards at home. 2 layer with soldermask and riveted vias in 1 hour if you work fast then 30 minutes. raw materials are cheap, so spinning a board 2-3 times to fix issues is not a problem... basically the time spent on making the PCBs is far less than troubleshooting "nonexistent problems" coming from breadboarding or hours spent on vero/proto-board prototype construction.

Do you drill the holes by hand, using a drill press or CNC?
In my experience this is the least fun part of the process, 0.5mm error here and there and it soon ends up looking like a mess.

proxxon drill drillpress with a cross table for sizes down to 0.6 mm in diameter, but most of the time not using the cross-table just hand positioning the board under the bit... with a little of practice you can be consistent with a error less than 0.2mm while hand positioning the board under the bit (holes etched into pads are helping a lot with positioning). smaller diameters downto 0.2mm i'm always drilling with a micro mill (proxxon MF70 - no cnc, hand cranked cross table). but mainly doing smt so the drilling is for vias and sometimes few holes for tht connectors or pin headers.

considering end-to-end effort + time still much better than protoboard.

and regarding wire-wrap... i think that's pointless nowadays except some very rare cases.

[e100]

No,  I'm not crazy.  I used to recycle electronics for extra cash,  and some of it was wire wrapped,  so I had to remove that to get better prices on recycled metals.  I tried to play with actual wiring at a time,  since technology was somewhat interesting.

As recently as 2001 NASA allowed wire wraps on space flight hardware.
http://workmanship.nasa.gov/lib/insp/2%20books/links/sections/301_discrete%20wiring.html

There's also a MIL spec updated for 2010
http://everyspec.com/MIL-STD/MIL-STD-1100-1299/download.php?spec=MIL-STD-1130C.040655.pdf

Just because something is non intuitive doesn't mean it should be ignored.
Much of the world's telecoms wiring uses solderless connections that rely on spring pressure or tension to create reliable "cold welds".

[BurningTantalum]

Gyro's post brought back happy memories- I too was taught how to wrap with the Vero cut and wrap gun; in fact I still have one somewhere. We also used a plain hand triggered gun but I cannot recall the manufacturer- I still have that somewhere too in a drawer marked O/S. I must have wrapped 10s of thousands of joints and I don't recall one bad one.
For prototyping we used a green plastic 'pen' that held a reel of fine wire on the end which had an insulating 'varnish' that melted away when soldered. It was so quick to wizz it round pins and even components and turned pin chip sockets (which I think it was designed for.) It may have also been a Vero product. It was, however, a bit of a nightmare to fault find and I recall my guru on more than one occasion shouting a vile obscenity and ripping the whole lot off the PCB and starting again.
BT

[Gyro]

Ugh, That was 'penwire', yes another Vero product. Horrible stuff! It had those plastic combs to 'organise' the wires through. One hot soldering iron jab in the wrong place and the whole thing would turn into a molten and probably shorted mess, nasty crosstalk too. They didn't tell you that you were breathing Cyanide fumes either!  I remeber quite a few ''outbursts' of frustration!

[PartialDischarge]

All of my prototypes are in proto PCBs with direct connections. The schematic is either in my head or handwritten in a piece of paper. Only when its stable I go to CAD.
This method is the fastest and allows me changes on the go. I understand this method is not for everyone though. Now I use a thin enameled magnet wire from belden that can be soldered easily.
In one of the pics note a bunch of epoxy that covers a tiny hand-soldered deadbug QFN

[RoGeorge]

Yes, I am still using wire wrap sometimes, for TH (Through Holes) only, but I am not wrapping the wire, I solder it on a prototype board. The advantage of soldering the wrap wire is that there is no need for wrap sockets, which are expensive and hard to find.

Here is a whole Z80 CPM/Spectrum computer (vintage) made with soldered wrapping wire:







https://hackaday.io/project/1411-xor-hobby-a-vintage-z80-computer-prototype



and a recent prototype for a DMX board with an ATmega8 MCU:





Since I don't have wrap sockets, I didn't actually wrapped a wire wrap for decades now.

[rstofer]

When wrapping, if there any difference in the quality of the connection when using an electric, hand powered trigger, or twist with the fingers type?
Does the electric type provide more consistent torque control?

Electrical cut-strip-wrap guns will provide a very uniform connection.
The sharp corners on gold plated wire-wrap pins work very well - in a conditioned environment.  Mainframe computers were mostly wire-wrapped but they lived in a favorable environment.

Part of the problem with hand wrapping is the need to strip the wire.  This is a PITA no matter what kind of stripper you have and I've had several.  I bought the cut-strip-wrap gun back in the early '80s and it still works today.  OTOH, I haven't used it lately.

If I'm doing logic, I'm going to do it in code on an FPGA.

Another gotcha is forming the wirellist from the netlist.  You absolutely want the ends of each wire placed at the same level.  Example:  If you are connecting pins 'a','b','c','d' then you want to wire 'a' to 'b' and 'c' to 'd' on the bottom level and then wire 'b' to 'c' on the top level.  This makes it possible to do some amount of rework without having to unwrap the entire net.  Of course this also implies that you minimize the wire lengths.  So, you need a simple program to accept the location of all the sockets (it can calculate the coordinates of the pins) and the netlist while figuring out the wirelist.  Decades ago, a friend wrote something like this in FORTRAN.

[coppice]

When wrapping, if there any difference in the quality of the connection when using an electric, hand powered trigger, or twist with the fingers type?
Does the electric type provide more consistent torque control?

A good wrap requires enough tension in the wire to make the corners of the pin bite into the wire and form a cold weld. If you unwrap a good wrap you can fell the cold welds breaking. Electric tools are generally really good at controlling the tension, and producing highly consistent wraps. The pistol style manual tools are pretty good, once you learn to hold them consistently as you pull in the grip. Its really hard to get consistent results with the simple stick type manual tools.