Listers,
Here's my 2 cents worth on this subject:
SOLDERED VERSUS CRIMPED CONNECTIONS
There is a lot of contention among the experts over this subject. Some people
swear by soldered joints, and others won't use them at all. My opinion is
that EITHER soldered or crimped joints are perfectly OK, provided they are
made correctly, and the rest of the wiring installation is correct. Vibration
is a problem only if there is a sufficient length of unsupported wire which
is allowed to move with respect to the connection. In other words, it is the
flexing of the wire that causes the wire to work harden and break.
Proponents of crimping say that solder wicks up the wire for a short length,
causing it to be stiff. This is true, and the problem area is the point where
the stiff portion of the wire meets the portion that is still flexible. This
is also a problem with crimped joints. The joint itself is very stiff,
exactly like the soldered joint. If the wire is allowed to flex, it will
break just the same as it would for a soldered joint. The one real
disadvantage of the solder joint is that the extra length of stiffening makes
it harder to route the wire, as the bend radius is larger.
SIMPLE RULES FOR MAKING GOOD TERMINATIONS
RULE # 1:
Never allow the connector to be the support for any appreciable length of
wire. The wire must be supported so there is no movement relative to the
connection. This is true even if you are wiring bewteen two components that
must move with respect to each other. The wire must be supported so there is
no movement AT THE TERMINAL!
RULE # 2:
A GOOD type X connection is better than a POOR type Y connection. Insert your
choice for X and Y. If I could get a good crimping tool, and good crimping
terminals, I would never make another soldered connection. The joints made by
the factory, using automated crimping tools, are unbeatable. The tools that
are available for the average person are only OK at best, and terrible if not
used properly. If you notice, the jaws on most crimping tools do not close
completely. If you use the correct size terminal, the correct size wire, and
the correct crimping tool opening, and squeeze till the tool stops, you will
produce a good crimp. Otherwise, it is possible to crimp too hard, and weaken
the wire and the terminal, or not hard enough, and get a weak connection. The
thing that bothers me the most about standard crimping tools is that they
crimp "across" the wire. This places a great deal of stress over a very small
area, making it very susceptable to breaking due to flex stressing. A "good"
crimping tool will make the crimp along the length of the wire, distributing
the stress over a larger area.
RULE # 3:
The material you are soldering must be hot enough to melt the solder. It
isn't good enough that the soldering iron melts the solder. If you touch the
solder to the iron till it melts, and let it flow around the wire, it will
produce a glob, and the solder will not stick to the wire. It may look like
it did, but it didn't. Unless the solder flows when touched to the wire, but
not touching the iron, the wire isn't hot enough. Unfortunately, if you hold
the solder to the wire, and wait til it is hot enough, the lenght of time
that takes may melt the insulation. A good technique to use is to melt a glob
of solder on the iron, where it touches the connection, and let it flow
around the connector. When the connector and the wire are hot enough to melt
the solder, you will see the blob of solder flow and smooth out. At this
time, the joint is hot enough to complete the soldering by adding more solder
to the joint. The glob of molten solder acts as a heat sink, transfering the
heat to the joint better than just the contact of the tip of the iron. When a
solder connection is made well, the solder flows smoothly, and basically
becomes one with the joint. If there is any abruptness in the solder flow, it
is probably a cold joint. In other words, if it looks like the solder is just
sticking on, it probably is just sticking on. A little practice with some
scrap wire and connectors will make this all clear.
RULE # 4:
Use the right heat range soldering iron/gun. Too big is better than too small
for our usage. A hot iron will get the joint to the proper temperature
quickly, so you can make the connection and get away before the heat has had
time to flow to adjacent areas, or up the wire. An iron that is too small
will take so long to get the joint hot enough that the wire will be hot for
an appreciable length, and might even damage the insulation before you can
finish. It is also helpful to use low temperature solder. Radio Shack sells a
roll of low temp solder that is just right for this purpose. In addition to
being low temp, it also has a small diameter, making it perfect for wiring
use. Whatever you do, don't use acid core solder, as it will cause severe
corrosion later.
TECHNIQUES FOR SOLDERING BULLET CONNECTORS
Soldering bullet connectors is actually pretty easy, once you get the hang of
it. The first thing to do is to make sure you have the right size for the
wire you are using. The bare wire should slip into the bullet easily, but
with as little excess room as possible. Strip the wire just long enough so
the wire end reaches the end of the hole in the bullet, and the insulation
just slips into the end of the bullet. With the bullet on the wire, hold the
iron to the bullet until it is hot enough to melt the solder by itself. Place
the solder to the hole in the end of the bullet, and allow the solder to wick
up into the bullet, until it has absorbed enough solder to completely fill
the void in and around the wire. This guarantees a good joint, as the solder
will not flow till the wire and the bullet are both hot enough. You can't get
a cold solder joint this way.
If you are making connections on your workbench, rather than in some
contorted position under the dash, you can simplify your process by clamping
the iron in a vice, thereby freeing both hands. Use one hand to hold the wire
and bullet against the iron, and the other to hand feed the solder. Working
this way, you can make a lot of GOOD joints in a hurry.
If you are working upside down under the dash, these connectors can be a real
pain, as they want to slip off the wire and hide in a crevice where they
can't be found. To reduce this problem, try to bend the wire so the wire end
is pointing upwards. It will help a lot if the wire is a snug fit in the
bullet.
BTW, when you buy the bullet connectors, buy the type that are designed for
crimping OR soldering, even if you are going to solder them, rather than the
type intended only for soldering. Why? They just work better for soldering.
They fit onto the wire a little bit snugger so they don't have as much
tendency to fall off while you are trying to solder them, and the finished
connection is just a little bit better.
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://members.aol.com/danmas/
'74 MGBGT---3000mile/year driver, original condition - slated for a V8 soon
'68 MGBGT---organ donor for the '74
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