The Shed – September-October 2019

44 The Shed 86 September/October 2019

By Greg Holster

Photographs: Jude Woodside

Welding

T

he term ‘MIG’ refers to ‘metal inert

gas’. MIG welding is also known as

‘gas metal arc welding’, or ‘GMAW’.

The welding is done with a shielding gas

which comes either from a gas bottle or

from the wire itself.

In the MIG welding process, there

is an electrical arc process in which

a continuous wire electrode is sent

through a MIG welding torch via a set of

motorized rollers and into a weld pool.

At the same time, a shielding gas of

either argon mixed with carbon dioxide

(CO 2 ) or straight CO 2 can also be sent

through the welding torch to create an

inert cover to protect the weld pool from

atmospheric contamination.

The basics of MIG welding are easy

to learn and you can easily be bitten by

the MIG welding bug. Once you start

making little projects and admiring

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grow. You will discover how simple it is

and your machine will get used more

and more. I can’t count the number of

times happy customers (women too)

have come back looking for a machine

the next size up, because the skills and

range of their welding have improved.

MIG welding, compared with stick or

arc welding, appears relatively complex

until the basics have been mastered.

With stick welding we have amperage

power settings and electrode size and

type as our main factors in setting up.

With MIG we have:

• amps (which control our wire speed)


• volts


• a choice of wire size and type


• gas or gasless wire
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  There can be too many choices. There
  are many single-phase, mobile MIG
  machines in sheds around the country
  that are more than likely not being
  used to their full potential because of
  simple problems such as wrong rollers,
  wrong-sized wire, wrong polarity or

Basics of

MIG welding

PART TWO: THE SECOND IN A SERIES

ON HOW TO WELD

44 The Shed 86 September/October 2019