Soldering is one of those tasks that you either really enjoy or greatly despise; RC maintenance is often like that. Even if you are a nitro guy, soldering comes-up more than you’d think, and if you run electric, soldering is a vital necessity. Most beginners—and some veterans—are intimidated by soldering jobs, but if you keep a few important tips in mind, soldering can be easy and will become something you look forward to, instead of cringe over.
Use a hot iron
Soldering is a lot easier when you start with a hot iron. Avoid using an iron that is less than 40W. Low wattage irons can put your equipment at risk, because holding the iron in place too long, waiting for the solder to melt, can easily damage your components by overheating.
Pick the right tip
There are a number of different soldering iron tips on the market, and they can be used for specific tasks. In general, however, stick with a broad-faced, chisel tip. The extra surface area on the tip will improve the contact surface, allowing for more efficient heat transfer. Unless you are forced to solder in a confined space, avoid fine-tipped irons.
Wipe the tip often
Before you start a new job, dampen a sponge and keep it handy. You should wipe the iron tip with the sponge before you tin a new surface, and wipe it off in between steps. Iron tips accumulate flux, oxidation and old solder quickly, and wiping them off allows for more efficient heat transfer.
Use an iron stand
Even if you don’t have a complete soldering station, you should at least purchase a coiled-wire iron stand. This gives you a place to keep a hot iron handy and will prevent you from burning your work bench and even yourself. Lying a hot iron on its side is dangerous and makes it difficult to use.
Especially if you are soldering on flat surfaces, it is always useful to rough-up (score) the surface with fine-grip sandpaper. Scoring the surface cleans it and increases surface area—both of which aid in making a strong bond and prevent the solder bead from running.
Any time you solder one surface to another, “pre-tin” both surfaces with a small amount of solder. When you move-on to binding the surfaces, the tinned areas will melt together much more easily than if one or both of the surfaces are naked.
Use a soldering jig
Although they may look ridiculous, investing in a soldering jig that uses alligator clips and a magnifying lens is a big help, especially when soldering connectors or wires to each other. The jig works as your third and forth hands—an invaluable resource considering that your first and second hands are full of the iron and solder itself.
Flux helps the flow
Most hobby-grade solder is infused with flux—as substance that improves the flow of melting solder. But for heavy-duty jobs with wide-gauged wires, brushing a little extra flux paste onto the surface before starting can help the melted solder flow and its heat remain homogenous.
Do the tug-test when done
When you are done with a job and the surfaces are sufficiently cooled, give the wire a quick, moderate tug. Solder isn’t bullet-proof, but a good connection should sustain a few pounds of pressure. If your connection beaks with a slight tug, the bond is bad, and it was just a matter of time before it came loose on its own.
Soldering is an acquired skill, much like trimming a body or gluing tires. The more you practice an acquired skill, the more tips and tricks you will learn by experience. If you are nervous about soldering, try practicing on an old wire, motor or battery first.