Before diving into the assembly of your brain game, we should go over the procedure for through-hole soldering.

Why is it called through-hole, you ask? You'll notice the circuit board has a bunch of holes in it, each with a copper trace on the underside of the board. The leads of each component are fed through these holes (hence through-hole) and soldered to the copper trace.

Through-hole soldering is generally regarded as the simplest form of soldering.

The most important tool for any soldering job? Your soldering iron, of course! For this procedure we'll be using the soldering station that we sell in our parts and tools store.

For this project, you won't want your soldering iron to exceed 40 watts at the tip. For our station which draws 50 watts of power from the wall, it is safe to crank it up all the way to max.

If this is the first time you're firing up your soldering iron, you may notice some smoke and a not-so-pleasant scent. Don't worry; this is just the coating on the tip burning off. Wait a couple minutes for the soldering iron to stop smoking.

Before you start soldering, be sure to dampen your cleaning sponge. A dry sponge will just get burned.

It is always a good precaution to wear safety goggles while soldering. Hot pieces of solder occasionally shoot off and a scorching piece of metal to the eye will ruin even the greatest optimist's day.

We'll start with resistor R1 in your kit, which has yellow, purple, brown, and gold rings on it (more on what these colored rings mean later).

Bend the leads of the resistor to 90^o angles about 1.5 mm away from the body of the resistor.

Place the leads of the resistor through the holes on either side of the rectangle marked R1 on the circuit board.

• Resistors do not have to be installed in a particular orientation. Either lead can go into either hole.

Turn the board over so that the copper traces are facing up and the resistor leads are pointing straight up in the air, as seen in the second picture

• You may also bend the leads outward to hold the resistor in place, but this is not necessary. As per NASA guidelines, any angle up to 30° down from vertical is acceptable.

You must be itching to throw down some molten metal by now; however, you still need to prepare the tip of your soldering iron.

Now that your soldering iron's tip is hot, clean it by melting a small amount of solder directly on the tip and wiping it off on your damp sponge.

Melt another small ball of solder onto the tip of the soldering iron, but do not wipe it off. This is called "tinning" the iron, and will improve heat conductivity, allowing you to solder more quickly and efficiently.

Regular cleaning and tinning of your soldering iron while working will lead to better solder joints and longer tip life.

Here we are: the moment of truth. It's time to get that solder flowing.

Set the tip of the soldering iron on the two parts to be connected. In this case, that's the resistor lead and the copper trace on the circuit board.

Touch your solder to the tip of your soldering iron to melt it onto the joint. Don't hold it there for more than a second or two.

Quickly, but not frantically, pull both the soldering iron and the solder away from the joint.

Your solder joint should be shiny and conical, and not expand beyond the copper trace.

Use the same method above to solder the second resistor lead to the circuit board.

• After soldering a joint, if you are going to put the soldering iron down, be sure to place it back in its stand to prevent burning yourself or anything around you.

Cut the extra lengths of the resistor leads with a pair of wire cutters. NASA workmanship standards state that any length up to 2.29 mm is acceptable.

We all make mistakes, especially when trying something new. Soldering is no exception, so here's what to do when one of your soldered joints comes out less than ideal.

Lay a strand of desoldering braid over the solder in question. Press the tip of the soldering iron firmly onto the desoldering braid. This will heat up both the solder and the braid.

• Be careful not to lay the desoldering braid across the fiberglass circuit board. As the braid heats up, it could leave marks in the board.

The solder should flow from the joint to the desoldering braid. After the solder flows into the braid, remove it and the soldering iron from the board. You should now have a clean contact to start over with. Use wire cutters to cut off the used end of the desoldering braid.