Equipment and Supplies
Before you can solder anything, you have to have the right equipment. This includes the obvious items like a soldering iron and solder, but should also include heat shrink tubing, something to shrink the tubing (heat gun, lighter, match, etc), wet sponge, holding/clamping device, wire strippers and/or cutters, wire of various sizes and connectors. Now let me show you what I use.
My tools and supplies include a Weller soldering station, a pair of needle nose pliers with some elastic webbing on them, 60/40 lead based solder, various heat shrink sizes and a lighter to shrink the tubing. I keep a supply of several sizes of noodle wire and several sets of spare connectors of various types.
For cutting/stripping wire I use several tools including my pocket
knife, scissors, dikes or a wire stripper. Which one I use depends on what
type and size of wire I am using.
Hint: A pair of needle nose pliers with something elastic around
the handles works great to hold the parts while you solder, or do any other task where you need the pliers to be "spring loaded".
Suggestion: Some use lead-free solder and this can make soldering much more difficult. I would recommend using a lead based solder. Just be sure to wash your hands after you solder.
Hardware suggestion: It has been brought to my attention that there is an alternative to using a sponge to clean your soldering iron tip. There are other types of cleaners that have little brass/copper curls in them and others that are brass/copper pads. These work very well for cleaning the tip without cooling it like a wet sponge.
Teaching by example
This article is going to be based on examples, the best way to learn in my opinion. I will start with a step-by-step how-to for soldering a T-Plug. Then the rest of the page will be filled with other examples as well as a few tips and tricks. Hopefully this collection of examples will cover all the various soldering concerns an rc hobbyist might encounter.
Step by Step soldering of a T-Plug connector
T-Plugs are very popular. They are not the easiest to solder but there are several things you can do to make it easier. So let me work through the steps needed.
1) Get everything setup and ready.
This usually starts with getting the soldering iron out, getting it plugged in to warm up and wetting the sponge.
Lay out all the parts so you have everything you need in one place. Next trim the insulation off the wires to match up with the connector tabs. You can trim the wires shorter but try not trim them too long.
Note: I suggest connecting the male and female connectors together for soldering. This will greatly reduce the chance of melting/distorting the housings due to the added thermal mass.
2) Prepping the surfaces, tinning
When tinning, try to do it quickly but well. Make sure your soldering iron is hot and clean. Before touching a part with the iron, add a small amount of solder to the tip.
Touch the part to be tinned with the wet solder and feed new solder into the angle between the two. Sometimes moving the iron around will help spread the solder more quickly. Once the part "takes" the solder, remove the iron. The solder should be smooth and shiny, if it is not shinny then add a tiny bit more.
Be careful how long you hold the iron on the parts. For smaller wires it
should not take any longer than about 1/2sec to tin the wires.
For larger wires it can take 2-3sec. If you heat the wires too much then
solder will wick up the wire under
the insulation and make it rigid. The prolonged heat will also boil off
all the flux and then the solder will not melt/flow well. The same
applies to the tabs on the connectors. For these you should just need to
wipe the solder across them to leave the surface tinned with just a
little bump of solder on them.
3) Complete the solder joints
This is going to be a very quick step. Before you solder anything, make sure your heat shrink tubing is on the wire. How far down the wire the shrink tubing it continues, how long you cut it, is your choice. The
heat shrink does provide some strain relief on the wire.
Clean your iron tip well and add a little bit of new solder. Then while holding the soldering iron in one hand, get your wire exactly where you want with other hand. In the situation below, lay the wire on the tab and get it lined up just like you want. Then place the part of the tip with the newly added solder directly on top of the wire and hold it until everything melts together. Once everything melts nicely together, remove the iron but continue to hold the wire in place while it cools enough to harden. The iron should not be in contact with the wire more than 1sec for smaller wires or more than about 3sec for larger wires.
Next comes a very important step, check your work. Take a good look at the solder joint and make sure it is smooth and clean. If not then try it again. Once you are happy with the new solder joint, it is time to shrink the heat shrink tubing.
Soldering an XT60 connector
The XT60 connectors are new to the RC world and are quickly becoming popular. Most of this lies in the fact that they are much easier to plug/unplug but they are also a little easier to solder than T-Plugs.
Soldering XT60s is very similar to T-Plugs. First get everything
laid out and ready. Next tin everything and then slide the heat
shrink tubing over the leads. Only add enough solder to just coat the inside of the solder cups.
To complete the joint, clean the iron and add some new solder. Hold the wire in place and lay the soldering iron on the wire to melt everything together. Again this should take very little time. Once everything looks good then slide the heat shrink up over the solder cup and into the relief molded into the connector, and shrink it.
Note about XT60s: These connectors are made of a fairly soft plastic that has a moderately low softening point. Be sure to only solder them while connected to their mate and be sure to be quick with the iron. They are not "fragile" but it should just me noted.
Not all rc connectors are molded plastic like T-Plugs and XT60s, many are either just a metal connector like bullets or are metal connectors that are housed in a plastic housing like EC3s, EC5s and Power Poles. The good news is that soldering bullets can be much simpler than other connectors. I am going to show how to unsolder a bullet and then re-solder it again. Then I will cover covering it.
The following connector came on a battery I recently ordered. Notice the lack of solder inside the hole? I would have never known it was not soldered well unless I had exposed the metal connector and seen that the solder cup was empty. As such I wanted to re-solder it to make sure I had a good connection.
Clean your iron and add a bit of fresh solder to it. Then hold the iron on the top edge of the connector until solder melts and you can remove the wire.
Now clamp the connector vertically and fill the cup 1/3 to 1/2 full of solder. Also re-tin the wire. Now heat the connector up for a few seconds and then place the wire in while keeping the iron on the side. When the two meld, you should see the solder pull in the hole some. At that point you can remove the iron but hold the wire in place until the solder cools.
In this case I have a problem. The heat shrink I used was just a tiny bit too small but I have a trick for that. In this case it is just a little too small. So I take the needle nose pliers and spread the heat shrink just enough to fit over the connector. Then I shrink it like normal.