Welders

Heat two ferrous-based metals sufficiently together so that they fuse and you have just employed the basic principals of the welding process. The metals involved - usually steel and stainless steel - are commonly known as the 'workpiece'. They are heated by an intense flame created either by electric arc or oxy-acetylene.

Welding involves using temperatures to 1000-1500º C. This heating creates weld joints, which are usually stronger than or as strong as the base materials being joined.

Choosing A Good Welder

Generally speaking, welding falls into three categories: Mig, Ark and Spot, and the type of welder you will require depends entirely on what kind of application you will be using most. Your work might range from construction and general maintenance to domestic, workshop or auto body/repair etc.

Welders are designed for specific applications depending on rated output, duty cycle and other features. Heavy duty repairs in the field, for example, require a package that can handle different sizes and types of metal, whereas repairing a wrought iron fence can be done using a stick welder.

Power Input Welding Guide

• Single-phase products require simple input power usually found in homes and garages (welders operate off either 115 or 230 Volts).
• If electrical connection is not available, a gas-powered, engine-driven welding generator can supply welding and auxiliary power.

Consider where you'll be working and the resources to hand. Can the welder be brought to the workpieces, or do the workpieces need to be brought to the welder? Accessories can be used to make most welders portable, though hand-portable welders are typically 70lbs or less.

Shielded Metal Arc Welders

Arc welding works by employing a consumable electrode to support the arc. Shielding is achieved by the melting of the outer flux coating on the electrode. Filler metal is obtained from the electrode core. This type of welding is good for windy, outdoor conditions and is effective when used on dirty or rusty metal.

Gas Metal Arc Welders

The gas metal arc process works with a wire feed welding machine. Metals are joined by heating them with an arc, which is between the continuously-fed filler metal electrode (solid wire) and the workpiece. Externally supplied gas or gas mixture provide shielding.

• Easy process to learn
• Better control on thinner metals
• Cleaner welds with less slag to clean
• Equipment can be used for Flux Cored welding

Recommended metal: Steel, stainless steel, aluminium, cast iron

Flux Cored Arc Welders (FCAW) - Gasless

Flux Cored Arc Welders use a process whereby metals are melted and joined by heating them with an arc between a continuous, consumable electrode wire and the workpiece. The weld is tubular with flux material contained inside the shielding. Added shielding may or may not be supplied from external gas or gas mixture, depending on the type of flux cored wire being used.

• Works well on dirty or rusty material
• Deep penetration for welding thick sections
• Can be used with or without shielding gas
• Self-shielded wire are best for windy conditions

Recommended to weld: Steel, stainless steel

Gas Tungsten Arc Welder (GTAW) - TIG

This welder uses a high-frequency generator. The arc is created between a non-consumable tungsten electrode and the workpiece. Filler metal may or may not be used, and argon inert gas or inert gas mixtures are used for shielding.

• Provides high-quality, precise welds
• Highly aesthetic weld beads

Recommended:
(AC TIG): aluminium, magnesium alloys
(DC TIG): steel, stainless steel, copper, brass, titanium.

Resistance Spot Welding (RSW)

Two separate pieces of metal are joined by passing current between electrodes positioned on opposite sides of the workpieces. No arc is used; rather, it is the resistance of the metal to the current flow that fuses the pieces.

• Portable and easy to operate
• Ideal for light industrial applications prepared

Recommended: steel, stainless steel

Plasma Cutting Torch

Plasma cutters are ideal for cutting and fabricating metal - from thin sheets to thick beams. Plasma cutting employs a torch, which uses a powerful electric arc to create plasma, made by boosting a gas (nitrogen, argon or oxygen) to a very high temperature. This creates a stream, or cone, of directed plasma that can reach a temperature of 30,000°F. Handheld torches can usually cut up to 1/2 in (13 mm) thick steel plate, and stronger computer-controlled torches can pierce and cut steel up to 12 inches (300 mm) thick. Unlike laser cutting, for example, the process of plasma cutting is only effective on materials that conduct electricity.