Copyright (c) 2010 Nadine Davis

Aluminium has become so common place in our society that we forget that, not long ago, it was considered to be a wonder metal. Light, flexible and corrosion resistant, it was welcomed into a market ripe for the creation of new products. This was not without its challenges, however, as it required a range of new skills different from traditional welding, and also new welding equipment and consumables. Initially, only small numbers of specialised welders had the skills to weld and shape aluminium but as its popularity and reliability grew, more and more tradespeople used welding standards to update their skills so that now, most fabrication shops can undertake aluminium work.

Aluminium can be a difficult metal to work with, especially for those experienced only in steel welding, and care must be taken to get the best result. Aluminium Fabrication welders are aware that what works for steel may not work for aluminium. There are three areas in particular that need to be addressed:

1. The set-up and associated techniques.

2. Power sources.

3. Three ways to feed the aluminium wire.

As this is a large subject, the set-up will be discussed here, and the other areas will be addressed in a subsequent article.

The Set-up and associated techniques.

The following changes to steel settings and equipment are required:

=> Liner and Wire Guides: a helically wound steel liner is not suitable as it would scratch the soft aluminium wire creating shavings. Use a Teflon or nylon liner and wire guides to reduce friction and eliminate shavings.

=> Drive Rolls: Use a U-shaped groove in the drive rolls to eliminate sharp edges that will shave off the aluminium wire. Reduce the tension on the drive roll to stop the wire from crushing during feeding.

=> Contact Tips: A bigger hole is needed for aluminium than for steel, as the aluminium expands further than steel when heated. Purchase contact tips designed especially for aluminium to prevent poor electrical contact.

=> Brake Tension: The brake tension on the wire spindle should be set more loosely than you would for steel in order to reduce the force necessary to pull the wire from the spool.

=> Gun Cables: Keep the gun as straight as possible to minimize tangling. The column strength of aluminium makes it much more difficult to feed.

The softness of the metal is the most difficult thing that people new to welding aluminium must consider. The danger of scratching the soft wire and creating shavings that cause other problems is ever present so welders used to Pipe Fabrication work need to make these recommended changes in the set-up stage.