Elenco Surface Mount Technology Kit - Manual (Page 6)

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Soldering Tips
The most important factor in assembling your SM-200K
Decision Maker is good soldering techniques. Many
areas on the printed circuit board are close together
and care must be given not to form solder shorts.
Solder shorts may occur if you accidentally touch an
adjacent foil, particularly a previously soldered
connection, using too much solder, or dragging the iron
across adjacent foils. If a solder short occurs, remove
it with your hot iron. Use only rosin core solder. Before
soldering the SM-200K board should be taped to the
workbench to keep it from moving when touched with
the soldering iron. For a good soldering job, the areas
being soldered must be heated sufficiently so that the
solder flows freely. When soldering surface mount
resistors and capacitors, the following procedure may
be used:
1. Using tweezers, place the surface mount
component on the PC board pads and secure in
place with tape.
2. Apply a small amount of solder to the soldering
iron tip. This allows the heat to leave the iron and
flow onto the foil.
3. Place the iron in contact with the PC board foil.
Apply a small amount of solder simultaneously to
the foil and the component and allow them to
melt the solder.
4. Remove the iron and allow the solder to cool.
The solder should have flowed freely and not
lump up around the component.
5. Remove the tape and solder the other side of the
component.
When soldering the transistors, diodes and
integrated circuits, the following procedure may be
used:
1. Place the component on the PC board pads and
secure in place with tape.
2. Apply a small amount of solder to the soldering
iron tip.
3. Place the soldering iron tip on top of the
component lead to be soldered and apply solder
simultaneously to the lead and the PC board foil.
4. Remove the iron and allow the solder to cool.
The solder should have flowed freely and not
lump up around the component.
After a component is completely soldered, each
solder joint should be inspected with a magnifying
glass. If the solder has not flowed smoothly, a bad
solder joint is indicated.
This occurs when the component and pad have not
been heated sufficiently. To correct, reheat the
connection and if necessary add a small amount of
additional solder.
Another way to solder surface mount components is
as follows:
1. Apply a small amount of solder to the soldering
iron tip.
2. Using tweezers, hold the component on the PC
board pads.
3. Apply the soldering iron simultaneously to the
component and pad and allow the solder to flow
around the component.
4. Remove the soldering iron and allow the
connection to cool.
Solder