[Milsurplus] Wire harness questions

[Michael Hanz]

On 5/27/2018 6:16 PM, Jim Whartenby wrote:
> Plan to use some white PVC 18 AWG wire to make up several wire 
> harnesses for various mil-radio projects.  The wire more or less chose 
> me since a spool of about 4000 feet was just about free.  The wire is 
> marked Style 1007 or 1569 which is rated at 105 deg C and is 16 
> strands of 30 AWG.
>
> Can I use the Ideal "T" Stripper tool or should I go with a thermal 
> wire stripper?  Both are available but mechanical stripping seems so 
> much faster.  The T-Stripper does an excellent job, I see no wire 
> nicks where the tool cuts the insulation.

I think you just answered the question, Jim - whatever works! :-)

> Plan to use braided insulation to protect the wire harness.  Do I need 
> to lace the wire bundle before I put the braid weave over the 
> completed harness?  I still have most of the roll of waxed nylon 
> lacing that I got some 50 years ago when I was a member of USAF.  The 
> stuff never seems to go bad!

I'm not sure why you would need to lace it if you are using sleeving.  
Lacing it _will_ make the wire bundle more stiff to route around the 
equipment if that's what you want, but I just slide the bundle into the 
sleeving/conduit/whatever and forget it. Heh...when you're upside down 
under the equipment you might appreciate a bit of flexibility.

> Plan to use a solder pot to tin the wire.  How often does one replace 
> the solder?  I know that tinning gold plated parts contaminates the 
> solder pot but is there any issue with standard tinned wire?

I've used both, but frankly the solder pot is more trouble than it's 
worth.  You have to keep cleaning the oxidation dross off of the 
surface, and for me it's easier to tin the wire with the iron just 
before insertion, or even not to tin it at all unless the wire is 
oxidized - just shove it into the solder cup and hold it there with some 
kind of tweezer assembly, then solder it in place.  Pretinning may add 
enough diameter to make it difficult to get the wire in the solder pot.  
Using PVC, you'll find the insulation melts _very_ quickly, so any heat 
you can keep away from it earlier will help. If the cable isn't going to 
be an open wire version with original WWII aircraft wire (i.e. using a 
cover or conduit,) I have tended to use teflon insulated wire to avoid 
the melting problem.  Using a 2%-3% silver bearing solder will help.  
(Tektronix was right...) Also, using some 1/2"-3/4"pieces of fiberglass 
or teflon sleeving over each wire will keep the chance of later contact 
between melted insulation on wires down to a minimum.  (Shrink tubing 
can also be used but interferes with your plan to keep later options 
open...it's tough to cut off after shrinking.)

> The connectors I have for the project are crimp contact mainly because 
> they were available.  But I plan to solder them so I can make any 
> needed changes as the project progresses.  I think I have the proper 
> tools to insert and remove the contacts from the connector shell.  Any 
> issues doing it this way?

Seems entirely reasonable.

      73,
  - Mike  KC4TOS
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