In a message dated 11/29/2004 2:58:49 AM Eastern Standard Time,
europa-list-digest@matronics.com writes:
> So my answer would be to solder on your extensions and then, yes, apply
> heat
> shrink.
>
> Hi all,
>
> Being that my chosen profession is that of an Electrical Engineer and being
> that my specialty is audio, telecom and radio frequency applications with
> roughly 7,000 cellular telephone and microwave site installations under my
> belt,
> I thought I'd chime in here with my experiences FWIW.
>
> Based on what I've experienced in the past 16 years of field work, I would
> agree with Richard that you should indeed solder connections, including those
> crimped "solderless" fittings, provided that they are copper or tinned copper
> and particularly those which are low current applications. I would not
> bother soldering battery leads as there is a better way to harness that beast.
Over time, unsoldered, unprotected crimped fittings will eventually corrode.
I've seen it over and over in the field. While > this may not be a huge
> problem in the long haul for battery leads or other high current circuits,
> smaller
> connections which corrode over time will, without a doubt, cause problems. I
> would recommend that for audio and other low voltage, low current circuits,
> i.e., headset leads, data leads, etc., be crimped using the proper tool, then
> soldered and covered with heat shrink whenever possible. Also, use high
> quality connectors with gold plated pins for the best results on audio, data
and
> other low voltage, low current applications. I like Amp connectors and a wide
> selection is available from www.digikey.com.
Battery lead crimps are better protected over the long run if the stripped
ends are
> dipped in "copper coat," "copper-ox" or "al-ox" or other similar
> anticorrosion medium prior to crimping. This stuff is available from any
> electrical
> supply house. For copper to copper connections I like a product called
> "Penetrox". This stuff is a paste made from conductive grease mixed with
> copper
> powder. Nothing I've seen works better for corrosion protection of large
> crimped
> leads, (welding wire, battery leads, etc.) even outside right next to the
> ocean. Simply dip the stripped cable end into the anticorrosion medium, then
> insert the wire in the connector and crimp as usual. Wipe off any excess
> Penetrox
> and cover the crimp and about 3/4" of the cable end with heat shrink for best
> results. Don't get this stuff on your clothes, though. Penetrox stains are
> permanent.
>
> Perhaps as important as soldering is using the right crimp tool for the job.
> By and large, from my experience, the crimper/stripper tools that come in
> the kits with the solderless connectors are junk. They make good paperweights,
> but that's about where their usefulness ends. They simply mash the connector
> flat over the wire and provide neither a good electrical bond, nor a good
> mechanical bond. Klein tools makes an excellent crimping tool, commonly
> referred
> to as a "Stay-con" tool. This tool uses a two sided die, one side being "U"
> shaped and the other having a pin that squeezes the fitting and wire together
> inside the "U" shaped die. These are available at most electrical supply
> stores and larger home improvement centers and are excellent for crimping AWG
10
> - 22 sized wires to insulated or non-insulated barrel type terminals.
> Another source we frequently use is Techni-Tool. www.techni-tool.com. They
> have a
> lot of specialty electronic tools and supplies. The Techni-Tool part number
> for the Klein tool I describe here is 490ST016. Once wires and barrel type
> connectors are crimped with this tool they do not come apart.
Audio and data pins (open barrel type) should only be crimped with an open
barrel type crimping tool. This is called an "F" type crimp and also uses a
two sided die. Techni-Tool carries a decent, relatively cheap ($25) version of
this tool. (Part # 694ST128) You can probably source this at any decent
electrical supply house that caters to audio installers too. "F" type connectors
usually have two sets of tabs which need to be crimped, one set for the bare
wire
providing the electrical connection and one set for providing a mechanical
connection to the wire jacket. This tool "rolls" the tabs of the connector
inward back onto the wire in one, easy motion. A second crimp will "roll" the
longer holding tabs onto the insulation jacket, generally using the next size
larger from the wire crimp. Open barrel connectors should be lightly soldered
after
crimping taking great care to not overheat the connector. Overheating the
connector pin will weaken it. On small wires (AWG18 or smaller) solder using a
small iron, 15w -25w, and keep a wet sponge handy to keep the tip clean. Re-tin
the tip often. Remember, you're not welding here. A little bit of solder goes
a long way.
My preferred method of joining two stranded wires is to strip back about 1/2"
on each wire. Be sure to use the right sized stripping tool or you will
weaken the wire. Slide the appropriate sized piece of heat shrink over one wire.
The shrink should be long enough so that it will cover the splice, plus about
1/2" onto each wire. Push the ends of the wires together so that the cut end
pushes into the other wire up to the point where it was stripped, then give it
a
slight twist. The idea here is to "weave" the two ends together. Lightly
solder the ends together and cover with heat shrink. This makes a neat, strong
connection.
Anyway, this is what I've found over the years that works. Hope it helps!
Regards,
John Lawton
Dunlap, TN
A-245 (Wet sanding my bottom (fuselage, that is))
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