We are fully operational and open for business as usual - our trade counter remains closed.
Significant disruption is expected for deliveries to Europe and Ireland due to Brexit/COVID


Years ago aluminium was considered a difficult material to weld, since when using oxy-acetylene there was no change in colour to indicate the metal’s temperature and suddenly it would melt and collapse. With the introduction of TIG and MIG welding processes these welder ‘fears’ have been put to one side, providing that the properties of aluminium are understood.

Aluminium and its alloys have special properties of lightness, strength, conductivity, malleability etc… which make it a very useful material in many industries. The metal can be either in ‘cast’ form or extruded (wrought), which then divides into non-heat treatable and heat treatable. Generally it is readily weldable but it’s important to understand some of its characteristics:

TIG welder aluminium filler rods


Oxidation: in air aluminium immediately forms an oxide layer on its surface, which will increase in thickness with time. This oxide layer must be controlled during the welding process, by chemically and mechanically cleaning the metal, using an aggressive flux or ensure that the arc has reverse polarity (electrode positive). Correct gas shielding (argon) will prevent oxides reforming in the weld.

Thermal: as aluminium is a very good thermal conductor it will rapidly disperse heat. Care must be taken to avoid distortion or possibly cracking.

Colour: unlike steel, there is no change in colour as it is being treated. Look out for a ‘wet’ appearance. For gas brazing, melting of flux powder is a temperature indicator.

Preparation: smooth all edges of workpiece to minimise trapped dirt. Use a commercial degreaser and stainless steel brush to remove dirt, oil and paint. Dry the surface thoroughly. If TIG welding, wipe the filler rod clean of any surface oil.

: support the joint to be welded, preferably with a jig, but spot tacking can be used. Keeps the arc travelling at the right speed to build up a bead of the right proportions. Do not stop/start on one weld as this can lead to oxidation/porosity. Carry out the weld quickly to avoid distortion.

Consumables for MIG and TIG welding:
4043A (no.15): contains 5% Silicon, for castings and heat treatable alloys 6063, 6061 and 6083. Weld will discolour if anodised. Good all purpose rod.

5356 (no.27): contains 5% Magnesium, for similar 5xxx alloys and heat treatable alloys 6063, 6061 and 6083. Has good corrosion resistance.
For pure aluminium, military, aerospace or significant load-bearing applications please contact us and we will advise on the correct rod for any given application.

Alloy MIG wire

Supporting You Welding

The combination of proven welding equipment, experience and skills is the key to successful welding.
We can help with welding guides, phone advice or welding videos…

How to Tig Weld

TIG welding may not be the easiest form of welding but learning how to TIG weld certainly rewards the effort…

How to Mig Weld

MIG welding may be one of the easier welding techniques but learning the finer points of the MIG welder’s art takes a little longer…

How to Plasma Cut

Welding metal is important, but sometimes you need a fast, accurate way to cut the stuff. That’s where plasma cutting comes into its own…

How to TIG Weld Video

Reading about TIG welding is one thing, but watching an experienced welder demonstrate the TIG art is something else…

Get our latest news and offers direct to your inbox

Talk to the R-Tech Team

With over 130 years’ combined experience in welding and welding equipment, we’ve got the information, answers and products you need. Let’s talk welding!


Paypal Visa American Express Mastercard

SecurityMetrics Credit Card Safe