- Hey I'm Matt Lewis with Hagerty.
In today's DIY we're going to go in-depth with soldering.
Now we do have a few different options for soldering irons.
This is a fairly common pencil soldering iron
that plugs into the wall.
Here I've got a butane soldering iron
that's super nice to have if you don't have power.
And then I have a big soldering gun
for doing those bigger jobs that take a lot more heat.
And as we've seen before, my two favorite tools
for working on wires, your auto strippers and your crimpers.
Most of the time when you're simply extending wires
or tying into an existing wire,
you're going to want to use the same size wire
from one to the other.
So here I've got a pair of 16-gauge wires, a blue and a red.
And we're going to go ahead and take the end off.
You want to come back 1/4 inch to 1/2 inch,
and give yourself some nice shiny copper wire as shown.
Older cars might have some corrosion;
the best way to get solder to stick
is have nice shiny wires,
so we're going to want to take a peek at that.
And then finally, personally I like to take the two,
twist them together like this.
Make that pre-connection before you start soldering.
So I've had my pencil soldering iron
warming up for a little wire here, and I'm going to go ahead
and get some solder into these wires.
For me, in order to make sure I get good penetration,
I like to heat one side of the grouping of wires
and apply solder to the other;
that way I know it's being pulled through
to the soldering iron.
And you can watch this copper wire
start to turn silver from the solder.
And once you see it do that,
and you get some good penetration,
and it's shiny and it's not gloppy,
that's a good way to know that you've got
a good connection between these wires.
And it's strong.
Soldering is a very strong method to hook wires together.
Not that you ever want to have wires with tension,
but you know that's not going to break apart
with the vibration of a car running down the road.
So there is a little bit of finesse to soldering.
You want to get the wires hot enough
to get the solder penetrated all the way in,
but you don't want it so hot that you start
melting the shielding off of the wire.
Now here I've got an example of a solder
that's very good and has great penetration.
It's wrapped all the way around this wire;
it's nice and silver.
And on the second one, this wire that we're attaching to
is quite a bit bigger.
A bigger wire's going to take longer to heat,
and as you can see, we've got
some good solder happening over here
but it never actually got into
the middle of this larger wire.
That's not going to be as good of a connection.
You definitely want to make sure you're heating it
long enough for the solder to pull in all the way.
So a second way you can connect these two wires together,
instead of putting them side by side
and twisting the wires together before we solder,
another option is to put them end to end,
try to weave the strands together,
and then twist so that they're sort of
almost braided or twisted together and will hold there.
The nice thing about this is,
when you go to put the shrink tube over it,
it's a nice smooth transition as opposed
to having more or less a lump that you would get
from twisting them, the other way.
All right, so like before, what we're going to want to do
is heat the opposite side of the wires
with our soldering iron, and then feed the solder in.
And you can actually see the point
it starts to pull into this wiring.
Once you have that nice and pulled through,
back off, and your connection's tight.
This wire does cool off pretty good.
I mean, it'll be hot for a minute,
so you're going to want to wait
before you put any shrink tube over it.
But the solder itself does harden really quick.
So as long as you have enough time
before you start moving the wires around,
you're going to be just fine.
Now sometimes on a car what you want to do
is add into an existing circuit,
so let's pretend that this wire isn't cut on either end;
it's running from one place to another inside the car.
You want to add a cigarette lighter,
you want to add a radio, something like that.
You don't want to have to cut into this wire to solder it,
so what you can do is take the auto strippers,
just put it in the middle of the wire,
and carefully pull back the housing.
Now you have an exposed piece of wire here.
We'll take our add-on wire,
and here I like to pull back a little additional
so I can wrap it around nicely.
Get that, and then what you can do
is simply wrap this around the original wire.
So we haven't cut this red wire,
but we're adding onto that circuit with this blue wire.
So now to solder this one, because we know
this red wire is thicker, we're going to want
to apply a little more heat, again being careful
that you're not melting all the plastic off.
But you have to make sure that the solder gets penetration.
And here we'll get things started.
Now this smaller wire's going to pull it in first.
So this takes quite a bit longer to heat up.
But once it's hot enough, you'll be able
to feed the solder into both wires.
Now we see that this thicker wire
is starting to pull the solder in
and the thinner wire has definitely
got the solder pulled in.
And there you can see, we have a nice add-on
for an existing wire.
After this you just want to let it cool,
because this wire did get quite warm.
And then wrap it with electrical tape.
They do make liquid electrical tape
but I prefer just regular electrical tape over it.
You can do both if you're cautious.
Now, there is an alternative to doing this.
So something that you'll often see
in fog light kits or add-on type accessories,
are these little guys here, and they're called Scotch Locks.
I do not advise using these ever.
So the way these work, if you've got an existing wire
you push it in here, right?
You take your new wire, you shove it in the other one.
Then you basically cram this piece of metal down,
cutting into both wires.
The issues I have with it, it's a very small connection
between these two wires, that the Scotch Lock will make.
And it physically cuts into both of them,
so if you have the wrong size Scotch Lock,
or you're not careful, what you can actually do
is cut this wire in half or worse,
and you'll lose a lot of the strands
that are inside the wire.
Everything in a car vibrates, so little things
that are dependent on tiny connections
or clamping down and that sort of thing,
they just don't function as well as soldering.
So take your time, solder it, do it right;
don't use this garbage, I hate 'em.
I hate 'em (echoing).
Now, another connector that I don't advise using
is something called a wire nut.
You see these all the time homes, which is great;
you've got a solid core wire, you're hooking two together,
you put a nut over it.
But guess what, your home doesn't drive down the street
and hit bumps; your car does.
So the idea is, you get your wires twisted together,
you take this nut and you just tighten down over it, right?
You've got a similar connection to my original solder here.
The problem is, that thing's going to vibrate,
it's going to come loose.
It's not a great connection between the two wires
and stranded wires just don't work very well under wire nuts
in my opinion.
So, again, take the time, do it right;
use a butt connector, solder the things together.
But avoid Scotch Locks and wire nuts,
because I just don't trust them.
Sometimes you're not going to be hooking two wires together;
what you're going to be doing is
attaching a wire to a terminal.
For that instance I'm going to take this switch
and I'm going to solder the wire onto it.
As I always do, twist up the end of this wire.
And here we're going to use something called tinning,
which comes from putting solder into the end of this wire
before we attach it to anything.
Solder is again, 60% tin.
We're going to get the end of this wire
nice and silver and shiny, full of solder.
Let it cool off for a second, because it's still quite hot.
Now the reason it makes it a whole lot easier
to tin this wire before I attach to this connector,
is the wire is actually going to hold the solder for me.
Also, it keeps the strands nice and bunched together
so while I'm putting it on here,
it keeps everything nice and tidy
and I've already got a reservoir of solder
ready to attach to this terminal.
So now we're going to take our nice tinned wire
and attach it to this terminal here on this switch.
What I like to do is put it through the hole here
and then bend it down, so that we've got
a nice flat piece up against our terminal.
Then what we're going to do is
take our nice warm soldering iron,
I'm going to heat up our wire,
let some additional solder flow in.
And attach it right to our terminal.
Once that solder cools down, again what you're looking for
is a nice shiny surface; you're not looking
for anything globby or cratered.
And that'll tell you that it's made
good attachment to that terminal.
So now I'm going to show an example of a cold solder
on this other terminal using this new wire.
Now I'm not going to tin this side;
I'm going to go ahead and feed it through,
bend it over like I did before.
So here we've got a good example of,
the solder is in the wire, but it didn't
actually connect to the terminal.
So this means that terminal did not get hot enough
to absorb the solder or to melt the solder,
which leaves us with a really bad connection.
Sometimes they aren't quite that loose,
but in an automobile instance you want everything
to be really well done, because they drive down the street,
they vibrate, they go over bumps,
and that's why it's so much more crucial
to get really good connections.
So even now I've added more solder.
It appears connected, but it's not nearly as nice.
Do you see how it's kind of bubbled up here,
it's still kind of a ball?
If we look at our original solder you can see
it's nice and cooled on the terminal that's well attached.
This is a much better attachment,
both electrically and for strength, than this one,
which over time I'm sure if it vibrated enough
and spent enough time in a car,
would break off and cause you issues.
So we've covered four different methods
of soldering connections: the side by side
that I've twisted together and soldered;
we've got an in-line solder;
attaching onto an exiting circuit;
we've got soldering onto a terminal.
They all work great, they're all nice and strong,
they're going to conduct electricity just fine.
So hopefully that helped you out.
If you have comments, leave them below.
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