HackSpace – September 2019

(Jacob Rumans) #1

Third hand


DIRECT FROM


SHENZHEN


Make soldering easier and avoid gassing yourself


By Ben Everard @ben_everard

T


hird hands are wonderful. They’re
devices for holding your work while
you solder. Typically, they include two
or more crocodile clips on movable
arms that can hold not only the
PCB, but also a component in place.
They’re so useful, we’d be tempted to call them
an essential part of an electronics tool-kit.
There are a few basic differences between
different models – how they attach to the
work surface, how many arms they have, how
flexible they are, and what extra attachments
they have. Let’s explore these a bit.
We’ve never had much luck with third hands
with suction cups to stick them down. These
never seem reliable enough in our experience.
Hands with screw clamps (similar to G-clamps)
can work, but only if you have a work surface they
can clamp to, and even then, they can only be on
the edge of the surface. Our favourite option, by
a significant margin, is those with a large, heavy
base that doesn’t need additional clamping.
Two arms work well: that gives you one to hold
the PCB and one to hold what you’re soldering,
provided you’re only soldering one thing at a time
and the PCB is light enough to be held by one arm.
For more complex soldering, three or four arms are
much better. Above about four arms, there seem
to be diminishing returns – we very seldom find
ourselves not able to hold our work in place with four.
There are two common types of arms: those
made out of metal rod with two or three joints, and
those that are almost endlessly flexible. There are
advantages and disadvantages to both. The rod-
and-joint style can be a bit tricky to get into position,
but usually can be locked with screws and are then
fixed in position. The more flexible arms are easy to
get into position, but can then wobble and move.

Above
Five extra hands and a
fan make soldering easier

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