Although there are
some prototyping boards that allow prototype circuits to be built without
soldering, at some stage you will need to commit to a more permanent
construction. When you do there is no better alternative than soldering.
It is a necessary skill whose subtleties are not always fully understood,
resulting in joints that don't work or will fail after a short time.
Put basically, soldering is
the joining of metals by a fusion of alloys, which have relatively low
melting points with the purpose of making an electrical and mechanical
connection. The following gives a brief overview of the basic technique.
You'll need a soldering iron, solder, and a wet sponge. Irons
of the 15W to 30W range are good for most electronics/printed circuit
board work. Using anything higher in wattage will risk damage to the
component or the pc board. Using the correct type of solder is also
important. Use a thin resin core solder.
For solder to properly adhere to a connection, the metals must be clean
and free of all non-metallic matter. You can clean a dirty lug or
component with a small steel-bristle brush designed for the purpose, you
can also use a solvent such as alcohol. For new components and fresh
circuit board it is not usually necessary.
When soldering, the idea is to apply the tip
to the connection and almost simultaneously apply the solder to the
junction between the tip and the connection. You want a small amount of
solder to flow between the iron tip and the wire or component, which aids
in transferring heat to the connections. The connection becomes hot enough
for the solder to flow onto it, forming a solder fillet between all the
Keep the soldering iron against the connection long enough to
"cook out" any flux residue, but not so long that the solder "burns up."
The time for the entire operation should be very short, just a matter of
seconds. Don't let the solder run down the tip, or try to heat up the
whole area first. Apply just enough solder to fill the gaps, and no more,
otherwise excess solder will flow into places where it is not needed, or where
it can cause a short. To complete the process, remove the solder first,
then the tip, being careful not to allow the connection to move while the
solder is solidifying.
A good connection is one where the solder has uniformly
flowed over all the surfaces to be connected, following their contours.
The connection appears bright, shiny, and smooth, with all wires in it
appearing well soldered. However, if the connection is rough, grainy, or
flaky looking, or if the solder formed into little round blobs, or has
ridges or sharp points, redo it. Take the time to visually check the
connection with those points in mind.
If the joint is a "cold" connection, caused either by insufficient heat, a
wire moving, or foreign matter (such as oxides) getting into the
connection, the cure is simple and direct: re-heat the joint and apply a
little more solder. If that would place too much solder in the joint, you
will have to remove the solder before trying again.