PREPARE YOUR WELDER
THE WELDING SET
The earth clamp [A] is connected to the workpiece. When the torch trigger [B] is pulled, welding wire [C] is fed by motorised rollers [D] to the torch, where it’s made live. A shielding gas [E] flows over the workpiece. When the wire contacts the metal, it causes a short circuit. This melts the wire and the metal.
Some sets have torches permanently attached, others have a Euro connection [A], which allows torches of different current capacities to be used. Wire is fed through a liner [B]. You can remove the gas shroud [C] and contact tip [D]. The tip can be recessed for thin metals or flush for thicker material.
MIG produces UV radiation and hot spatter. Get a welding mask that attaches to your head, as you’ll need both your hands. An auto version is best. Wear overalls, a skull cap and gauntlets, plus a leather jacket, earplugs and safety spectacles.
Wire is sold in 0.7, 5 and 15kg reels. It comes in 0.6, 0.8, 1.0mm and larger diameters. If you’re only going to be welding bodywork, go for 0.6mm wire. Otherwise, 0.8mm is most versatile. Buy good quality copper-coated steel wire. Never use rusty wire.
A mix of argon and CO2 is best for mild steel. A 95/5% Ar/CO2 mix is a good all-rounder. Pure CO2 creates a hotter weld, so isn’t ideal for thin metal. Disposable cylinders are convenient, but expensive. Larger cylinders can be connected with an adaptor.
SET GAS FLOW
Slowly open the main valve. The gauges read cylinder pressure and flow rate. Release the wire tension and pull the trigger. Screw in the regulator until the flow gauge reads 10-15 litres per minute… lower for small shrouds; higher if there’s a breeze.
MOUNT THE SPOOL
Fit the spool so it unwinds into the wirefeed rollers as directly as possible. Set the hub nut tension so the spool just stops dead after being spun. Detension or unlatch the rollers. One will be grooved. Ensure its markings show the correct wire diameter.
SET FEED TENSION
Snip off the wire’s end. Feed it through the rollers, then relatch them. Pull the trigger until wire emerges from the torch, then fit the contact tip and shroud. Set the tension so the wire just slips in the rollers when held against your gloved hand.
Match contact tip size to the diameter of the wire you’re using.