All circuit boards are double sided,
and all holes are plated through. This
means that one does not have to
(and should not!) solder on the
component side of the boards. In a
few cases (changes in the enclosure
originating with the vendor), it may
become necessary to place a
component on the conductor side of
the board. Always work with a
preheated soldering iron. If you are
able to set the temperature of the
iron, use 350°C to 400°C. Use a
minimal soldering time! Beginners,
particularly, have a tendency to stay
on a solder point too long, detaching
a conductor trace and applying an
excess of solder. One should never
use any additional soldering aids
such as liquid flux, soldering paste.
Modern-day solder for electronics
use contains a core of flux that
already serves this purpose.
■ Lead-Free, If You Please!
At present, there are solders of
various compositions. The high toxic
lead content makes it necessary to
comply with the provisions of EHS!
During soldering, do not place your
nose directly in the smoke coming
from the operation! Commercially-
available so-called "environmentally
friendly" solder has not been proven
in practice. The cheapest and most
widely used alloy, called Sn64Pb36,
consists of 64% tin and 36% lead.
Compositions with 2% copper or
silver have a lower melting point,
which makes the soldering
somewhat easier, and the joints are
noticeably shiny.
The latter has of course no particular
electrical significance, but pleases
many hobbyists. Whether you use
silver or copper based solder makes
no real difference except to your
wallet!
■ 30-50 Watt Soldering
Station
A soldering station that works with
low voltage and potential
equalization is optimum. Please do
not use one of the old soldering iron
models, in which the tip is inserted
into the core and held in place by a
screw. In this old style iron, the tip is
often poorly held in the heating
element and has, on this account,
very poor heat transfer. If you need
to buy a new iron, please buy a
modern one. These irons have a
plated tip and are pre-tinned.
Keep the soldering iron tip clean as
you work. Use a damp sponge or a
damp cloth to clean the tip regularly.
An 0.8 to 1.0 mm tip is ideal for
normal circuit board traces. For
large-area surfaces, this kind of tip is
not really suitable, and a somewhat
broader tip (so-called chisel point) is
advantageous because of the
improved heat transfer. At least
these two tip types are useful. They
can be interchanged when it
becomes necessary to solder, e.g.,
some large flat surface. Only heat
the point being soldered just
sufficiently to give a good
connection.
A small circuit board holder makes
working on the board easier.
