PRE­PARE YOUR WELDER

Unique Cars - - WORKSHOP BASICS -

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.

THE TORCH

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.

PRO­TEC­TIVE EQUIP­MENT

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.

WELD­ING WIRE

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.

SHIELD­ING GAS

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.

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