Page 403 - Robot Builder's Bonanza

372 BUILDING ROBOT ELECTRONICS— THE BASICS

Figure 30- 7 Parts of the soldering
pencil. Be sure yours is a three- wire
grounded model. Don’t use an ungrounded
soldering tool for electronics work. The
replaceable tip is a good feature. When it’s
worn, you can get a new tip rather than a
whole new soldering pencil.

off while you’re soldering and ruin the connection. In a pinch, you can substitute a wetted and
folded- up paper towel or napkin. Be sure it stays wet— you don’t want it to catch fire when
you try to clean the soldering tip against it!

Solder
Use only rosin core solder approved for use in electronic circuits. It comes in different thick-
nesses. For best results, use the thin type (0.050″) for most of your electronics. Don’t use acid
core or silver solder on electronic equipment. (Note: Certain “silver- bearing” solders are avail-
able for specialty electronics work, and they are acceptable to use.)
For noncommercial applications, you have the option of lead- bearing or lead- free solders.
Both are safe to use when handled properly, but even the lead- free type can be toxic if
ingested. Lead- bearing solder is a bit cheaper and easier to work with, as it has a lower melt-
ing temperature.

Miscellaneous Soldering Tools
And there are a few more soldering tools worth mentioning:

• A heat sink looks like a small metal clamp. It’s used to draw heat away from components
during soldering.
• Ordinary household isopropyl alcohol makes a good, all- around soldering cleaner. After
soldering, and when the components and board are cool, clean the board with rosin flux
remover.
• A solder vacuum (or “solder sucker”) is a suction device used to remove excess solder. It is
often used when desoldering— that is, removing a wire or component from the board, so
that you can fix a mistake.

CLEANING THINGS PRIOR TO SOLDERING
Before soldering, make sure all parts of the connection are clean. If you’re soldering a com-
ponent onto a printed circuit board, clean the board first with warm water, a kitchen scouring
powder, and a nonmetallic scrubbing pad. Rinse thoroughly, and let dry.
Next, wet a cotton ball with normal household isopropyl alcohol and wipe off all the con-
nection points. Wait a minute for the alcohol to completely evaporate, then start soldering.

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