Basics of welding aluminium

Aluminium alloys are used in so many different applications in our modern world, from motorbike frames and boats, big and small, to super yachts. The list is endless. So when it comes to building, manufacturing, and repairs, welding is often the best solution. Most aluminium alloys are weldable, but it is important to understand the special aspects and quirks of working and welding aluminium and to figure out the best welding technique.

Clean it

Easily the most overlooked problem in welding aluminium is not having a clean welding preparation. So first up, cleanliness is of the utmost importance. When faced with repairs in the shed or workshop, you will find that aluminium that is old, dirty, or with an oxidized surface will need to be cleaned. Clean it up so you get rid of any paint or oxide film on the surface. Sometimes with cast aluminium, oil and grease can embed themselves into the parent metal. Use white spirit to clean the oil off before you use an abrasive. Aluminium oxide is that dull, matte, silvery-grey coating on the surface of all aluminium caused by contact with oxygen. This oxide melts at more than three times the temperature of the aluminium, so you can’t break through the skin if it’s oxidized. To remove all oxide, you need to clean it off, either by grinding or hand-sanding with an abrasive such as emery cloth.

“The cleanliness of the aluminium surface is important; the less oxide and dirt on the surface, the less power needed”

TIG welding

TIG welding uses a non-consumable tungsten electrode surrounded by a ceramic shield that controls the flow of the protecting argon gas. Argon gas shields the molten metal from the oxygen and nitrogen in the atmosphere