Homebrew PCBs

On Sat, 21 Apr 2007 11:05:19 +0200, Peter Harrison  
<peter.harrison@...> wrote:

> Hi
> When I need to use a bit or wirewrap wire to patch a board, I find it
> really hard to strip the ends without nicking the wire. Once nicked, it
> is only a matter of time before the wire fails at that point.
> Not only that, the insulation is tough and stripping back just 1mm from
> a 1inch length is a bit taxing.
> Anyone got any good tips or tool suggestions for this job? Or perhaps
> you use a different/better kind of wire for the task.
> Pete


Which isolation does your wire have?
There is usually a stripping tool on a manual wirewrapping tool, which  
should do the job. But they seemed way too much work to me and i always  
used the electrical tool so i have no experience how well/bad it works.

There is however something simple i made for a similar application.  
Commercial strippers often don't work very well for thin wires. So i  
started with a pair of miniature side-cutting pliers, and ground the flat  
side down so that they resemble electronics cutters like these:  
<http://www.minute-man.com/acatalog/ECLIPSE200-002.jpg> (you can skip the  
step alltogether, either buy electronics cutters to start with or the  
miniature side cutting pliers will probably still work even with the wider  
cutting edge. My tools shop does not carry electronics cutters and the  
small side cutting pliers are cheaper).

Now comes the important part: grind a notch in each side of the mouth with  
a proxxon (or dremel if you must) cutoff wheel. The notch must be small,  
just the diameter of the wire, and of course in the same place on both  
sides. If you grind the notch at an angle, so that a sharp blade results  
all-round, you will get the best result.

I made this custom/homemade wire stripper for a very special wire, it is  
triple isolated with a laquer layer over the wire then a layer of either  
silk or a synthetic fiber spun around it and then another layer of laquer.  
I have a great bunch of 2 meter pieces of that wire in many colors and  
color combinations. Somehow i got it into my head that i must use this  
wire for solderless breadboard links. You guess it: about a zillion ends  
to strip. We could discuss the sanity of using such a tricky wire for  
breadboard use, but i'd rather not.
Anyway, as you can guess, nicking the wire is not an option for  
breadboards. None of the strippers in my sizeable collection could deal  
with it, either it would leave the innermost laquer layer, or it would  
nick it, or it would badly fray the silk. The modified side cutting pliers  
with a notch of just the right size do a great job.

There is one special reason why i like the wire. If you put too much  
current across it (as in a short) the outer layer of isolation will  
blister/bubble up. This will show the path a short took without any real  
damage.

ST