Date: Sun, 31 Jan 1999 09:58:38 -0800
Reply-To: Davidson <wdavidson@THEGRID.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Davidson <wdavidson@THEGRID.NET>
Subject: Re: Soldered Connections...Not!
Content-Type: text/plain; charset="iso-8859-1"
So where do you get copper crimp on connectors? I think the only ones I've
ever seen for sale are aluminum (?). And many that came stock on vehicles
appear to be aluminum. But they don't seem to corrode.
Bill
90 Westy Syncro
-----Original Message-----
From: Carl Turner <CarlMarin@AOL.COM>
To: vanagon@GERRY.VANAGON.COM <vanagon@GERRY.VANAGON.COM>
Date: Sunday, January 31, 1999 9:43 AM
Subject: Re: Soldered Connections...Not!
>David Writes:
><<<<<<<
>Subject:Soldered Connections
>I think you are missing the point with soldering - or you have never seen
>it done correctly. Your examples of failing solders are not from a wire to
>wire connection but a wire to a component / circuit board connection. If
>you are soldering two wires together you must do what is called a "western
>union" connection first. This is where you strip the wires say 1.5 to
>2.0cm and put them parallel to each other so the cut end of one wire is
>next to the begining of the plastic covering of the other. Then twist the
>wires so they make a mechanical connection first. The wires should be able
>to hold together without solder. The next step is to do a propper
>soldering job where you heat the wire and not the solder thus advoiding a
>cold solder. Use decent solder that contains a very small amount of flux.
>I use the Radio Shack stuff. After you make this connection I will bet
>anyone one hundred bucks that it will NOT break. If you waterproof it with
>lithium greese and seal it with very snug heat shrink it is almost as good
>as an uncut wire - just a little stiffer where the connection is made.
>
>Crimps do have their place and work well when done with the right tools.
>They do tend to leave some part of the connection open to the atmosphere
>which makes it prone to rust and eventually failure.
><<<<<<<<<
>
>I'm afraid you'd loose that 100 dollars David! Soldered connections used
on
>equipment subject to vibration, cars, airplanes, rockets are especially
prone
>to fatique failure. The type of soldered joints used on connectors and
>splices in the mil-spec environment are highly speciallized and the specs
for
>how these wires are then harnessed and strain relieved are very specific.
The
>wiring on our Vanagons doesn't even come close to this standard. Most
wiring
>on General Aviation aircraft and most experimental homebuilt aircraft (as
Ken
>W. alluded to) is done with proper solderless crimp connections.
>
>A proper solderless crimp connection fits a proper size crimp fitting to
the
>gage wire, is compatible in material, ie copper on copper wire, aluminum on
>aluminum wire and so on. The joint is then "sealed" as it were with a
>generous length of shrink wrap that not only keeps out corrosive
environment
>but also serves to strain relieve the joint. One problem common to us all
I'm
>sure is working with the crappy crimp connectors they sell down at the
local
>flaps. They usually have some plastic cover with huge water catching cups
on
>the ends. I never really figured out what the point of those were. I
often
>just cut the plastic cover on these type of crimps off, slide one or two
>lengths of shrink wrap on the wire before crimping, do the crimp thing,
slide
>the heat shrink over the joint and warm it up ( proper heat gun, not a hair
>drier or a match please!) Resulting joints stay dry, and maintain the
>ductility of the base wire and should not corrode if you used the proper
>material crimp (remember dissimilar metals corrosion?) If the wire you are
>connecting is grubby, it should be cleaned with some scotchbrite before
>crimping. Really, the key to neat and tidy crimp connections is using
shrink
>wrap over top of them. Those blue and yellow plastic covered things they
sell
>at the auto parts store do not make for neat connections unless modified as
I
>described above .
>
>Now to the problems with soldering. Soldering can be used to solve
connection
>problems certainly. For example, you can't get a good fit for a crimp
>connection or you are joining wires of different gage or you can't get the
the
>store to buy the right crimp connections (I've been there, believe me!).
So
>what you want to do is try and create a solid mechanical connection before
you
>solder by twisting the wires together or whatever (or dare I say...use a
crimp
>sleeve) You then want to use a minumum amount of solder, not so much that
you
>coat the joint with a shiny blob of metal (I know, it looks good but its a
bad
>idea). What happens is the multistranded wire wicks the solder up along
the
>length of wire well away from the joint making that length of wire very
>brittle and prone to fatigue failure. The flux gets wicked up even further
>into the wire where it can have a corrosive effect over time (even rosen
>flux). Just take a bit of wire scrap and solder a really big blob of
solder
>to the end and really burn that baby in. When cool you'll be able to
actually
>feel how the wire has been stiffened under the insulation where the solder
>wicked up. So if solder you must, practice on some scraps till you can get
>the 1/4 inch at the end soldered but can still flex the wire beyond the
>soldered bit. You're on the right track now for an acceptable soldered
>connection. The joint should now be shrink wrapped, maybe a couple of
layers,
>each a little longer than the one underneath, to give a nice strain relief
to
>the wire. The wire should now be strain relieved with proper clamp in the
>installation so it isn't buzzing as you roll down the road or fly through
the
>wild blue yonder (depending on your personal conveyance of choice). As
>further argument in favor of my assertion, notice that all automotive
wiring
>used multistranded wire rather than single solid wire conductors. This is
for
>flexiblility and thus longer fatique life. By soldering your multistranded
>wire and binding up the strands for a significant length you are creating
>something that looks like solid single conductor wire. Anybody wiring
their
>cars with Romex?
>
>Carl Turner
>
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