Writeup: Soldering 101

Soldering 101
By Bob_98SR5
Date: 1/2/06

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Many of the mods from installing a stereo, hardwiring a radar detector, a winch, an alarm, etc will require soldering wires. Poorly soldered joints held by t-taps or fuse taps may separate over time and cause a poor connection that interrupts an adequate supply of power to a device. A good, soldered joint on the other hand, will be strong and will not fail. This is critical for things you do not necessarily want to fail at a bad time like winching or an alarm system. Thus, it is a good idea to understand the right way to soldering connections now rather than later.

Tools
Soldering Gun (preferred), but a soldering iron is marginally acceptable
Rosin Core solder
Old, but clean sponge
Water
Wire stripper
Wire cutter
Heat shrink tubing
Heat gun (not blow dryer)

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Step 1
Begin by cutting the ends of the wires for a clean end. Begin by stripping about an inch to an inch and a half of the protective covering off the wires. Twist them very tightly as this will help reduce the final diameter of the twisted wires. Next, twist the two wires together as tightly as possible.

http://4runners.org/image/solder/solder01.jpg

Of note, I used a box with two slits in it as a third hand to hold the wires. This is a good way to help you focus on proper soldering technique instead of trying to juggle all the tasks involved in soldering

Step 2
Before twisting the wires together, add about 2 inches or so of heat shrink tubing to one end.

http://4runners.org/image/solder/solder02.jpg

Step 3
Here are your most important tools. A good soldering gun, a wet sponge, and rosin core solder. Why do I prefer a soldering gun? First, it heats up VERY quickly and rapidly cools off. In contrast, most cheap soldering irons (usually priced under $10) take a few minutes to heat up and are always on. This is pretty dangerous and I have burnt myself pretty badly on my hand with a cheap soldering iron---thus, that is why I recommend a soldering gun! I ended up purchasing a $30 Weller model (Home Depot) and this one in particular has a little light at the end. I didn't think I'd appreciate it, but it does help in tight places where you can't get good light.

http://4runners.org/image/solder/solder03.jpg

Step 4
Begin by heating up the soldering iron and touch the solder onto the tip. A nice, silverly blob should form on the tip. Run the tip across your wet sponge to wipe off the excess solder. This process is called "tinning", and it is crucial for soldering because it creates a clean film of solder on the tip.

http://4runners.org/image/solder/solder04.jpg

Step 5
In this close up pic, you can see I am putting the tip of the soldering gun on the *wires* and NOT the rosin core solder. The most common and easily corrected mistake is touching the solder to the solder tip, dripping the solder onto the wires, and then spreading the solder on the wires like peanut butter and jelly on toast. This is the wrong way to do it. Instead as the picture shows, heat the wire itself and touch the solder to the wires. After a few seconds (depending on how hot your soldering gun reaches the ideal temperature), the solder will immediately flow through every seam in the twisted wires. The first time you do it right, I guarantee your will say "hmmm...cool"

http://4runners.org/image/solder/solder06.jpg

Step 6
Here is what a properly soldered joint looks like:

http://4runners.org/image/solder/solder07.jpg

Step 7
To finish, move the heat shrink tubing over the soldered joint and then heat the tubing up with your heat gun. If you don't have access to a heat gun, a match or lighter will do too. While many people use electrical tape, I don't because over time, the electrical tape starts to somewhat unravel itself and is not as clean and weather resistant as properly applied shrink tubing

http://4runners.org/image/solder/solder08.jpg