BoatBanter.com - If you have to solder

There seems to be differences of opinion regarding soldered
vs crimped terminals in a marine environment.

As others have pointed out, ABYC allows soldering, but only
in conjunction with a mechanical means of securing the wire
to the terminal. The only practical mechanical means of course
is a crimp connection.
One poster suggested the ABYC is changing this. Be interesting
to see the new rules.
A google search on this topic reveals about equal numbers of
those for and against soldering.

Based on my electronics experience (50 years, plus a NASA
course in soldering, for whatever that's worth), I'd recommend
the following procedures...for smaller guage wire, that is...

1. Buy proper marine wire. The cheapo wire packs sold in
auto parts stores (and I'd suspect in some marine stores
as well), are junk. Look at any utility trailer home-wired for
lights, and you'll notice the insulation falling off. Make sure the
wire construction is tinned copper conductors, at least 7 strands,
19 strands is better, and an insulation temp rating of at least 75C.
I buy nothing less than 105C wire myself. A nylon jacket over the
primary insulation is prefered. Use your soldering iron to "tin"
a few samples. If the solder doesn't immediatly flow, and just
beads up, the wire conductor is oxidized. Don't use it, even if you
intend to crimp and not solder.

2. Buy the proper crimp tool. A good one is expensive, but should
last a lifetime. I like crimpers which make double "elliptical" crimps
as opposed to the "indent" type. If you do use the indent style, make
sure the indent is opposite the barrel seam.

3. Use proper terminals. As in the case of wire, beware of the
cheap ones. The metal part should be tinned heavy-guage copper,
(solder test the terminal just as you did the wire), the barrel should
be seamless...actually the seams are usually brazed.
The rear of the barrel should include a insulation grip as well.
The terminal insulation should be temp rated equal to the wire,
but often isn't.

4. Try it out. Cut some new wire into a few 6" to 12" samples. Use
your new strippers to strip a bit of insulation from the ends. Inspect
the stripped end very closely, under a glass if you're not 21 or
younger, and verify that the insulation was cut cleanly, and that no
strands were nicked, not even a little. Why? Because nicks will
expose bare copper, which will oxidize pretty quickly. You may
have to strip off a bit more to see the area of the original strip.

5. Crimp a few terminals on your wire samples. Try to pull the
terminal from the wire. You shouldn't be able to. The wire should
break first.
Use a Exacto knife (or equiv) to remove the terminal insulation.
Inspect the crimp area for signs of over crimping...exposed copper,
tears, etc.

6. If you're the belt-and-suspenders type, and you just have to
solder the terminal, here's how. After the terminal has been
properly crimped, you should see the end of the wire exposed
at the ring end of the terminal, if that makes sense. If the end of
the wire is not even with, or slightly protruding (.020"), from the barrel,
you're not stripping quite enough insulation.
Then buy, beg, or steal from your electronics buddy some very
small diameter (no larger than 18 guage, and new!!) rosin-core solder.
Organic flux solder is better if you can find it.
Use a fine tip soldering iron (I use a 15W pencil iron) to heat the
junction of the wire and terminal, then touch the solder to the exposed
wire. The goal is to just "paint" the end of the wire. Resist the temptation
to make another "pass".
If properly done, a glass should reveal the indivdual strands, and
a very tiny fillet of solder between the wire and the terminal.
NASA has shown over and over this is sufficient to make a proper
solder connection, even if it doesn't look like it.
If the solder joint looks like a blob, and hides the wire strands, you've used
too much solder. A bit of practice will be invaluable before doing
it for real on the boat.

A "2-bits worth" observation while I'm on my soapbox....
A lot of power distribution panels are
works of art. Labels, wire ties, neat routing, etc. But one thing I've see
missing most often are drip loops and service loops. Drip loops
ensure that water does not run onto the terminal if the wire is wetted.
Service loops are an extra bit of wire (can be combined with
drip loops), so that if a terminal does need to be replaced,
you can cut back to fresh copper, and install a new terminal.
On terminal blocks and bus bars, I tie wrap the "bundle" at
every wire, and the bundle to something solid every 2" or so.
(I still use nylon lacing cord...old habit I guess). The idea is to
make the natural frequency of the unsupported portion of the
wire much higher than any vibration likely to be encountered on
a boat.
If you choose to use this method, do not tie the bundle to metal.
Reason? Most PVC insulation materials will "cold flow" and
eventually allow the conductor to contact the metal. A nylon
jacket is helpful in this regard.

As always,double (heavy) wall heat shrink tubing is a good idea.
(Again, don't use the cheap stuff from Radio Shack)

Hope the above is somewhat useful to you.
Norm B