How to Solder
Soldering is one of the more useful skills when it comes to building a model railroad. It can also be intimidating and a source of frustration for those that haven’t done it before. Like anything else, it really is not that difficult IF you use the right materials and techniques.
Tip 1: Use a HOT soldering gun. I prefer a 40 watt pencil gun. These are available from Radio Shack for about ten dollars, or you can buy them with your components from online retailers such as Octopart.
Tip 2: Use a high quality liquid flux for quick and reliable heat transfer. This is one of the biggest difference makers in terms of getting a successful result. Using flux will largely eliminate the problem of having your plastic ties melt long before the rail is hot enough to melt the solder. I prefer liquid flux from Team Trinity (part #5004). http://www.teamtrinity.com/ When applying flux, a “dab will do you”. A small drop on the objects being soldered will do the job. Don’t put on too much or you’ll have a brown residue that will need to be cleaned up later. The solder itself produces a toxic smoke that needs to be extracted, make sure you do this near a window as you probably won’t have an extraction system by Integrated Air Systems in your home!
Tip 3: Use thin solder. I prefer .032″ diameter available at Radio Shack.
Tip 4: Make sure the items being soldered are reasonably clean and free of paint, oxidation and residue.
Tip 5: Let BOTH of the OBJECTS BEING SOLDERED melt the solder, NOT the tip of the gun. For example, if you are soldering a wire to the rail, put the wire tight against the rail, apply a drop of flux and hold the soldering iron tip tight against the wire pushing it tight against rail. There are no doubts about, soldering is a precise and skilled activity and, therefore, you need to be certain that the flux core wire for aluminium and thin metal that you are using is of a high quality. Make sure both objects are hot enough to melt the solder. They should heat up quickly. If one is hot and the other is cold you may get a partial bond but it will likely be of questionable integrity. When both objects being soldered are hot, touch your solder against the object being heated and in a few seconds the solder should should flow like water. Finally, remove the gun and let the solder cool.
Final Tip: Keep your soldering iron tip clean. After a few uses you’ll see some charcoal type material building up on the tip of your gun. A few passes with jewelers file will quickly clean if off. If you don’t keep it clean you’ll quickly notice it takes much longer to heat things up.
Safety Reminder: Remember to turn off your gun before leaving the room. Never leave a hot soldering gun un-attended.