When welding, it is very important that you choose the correct wire in relation to the base metal. So when you’re welding aluminum, you must use aluminum welding wire, and should select one that has a similar melting temperature to your base metal. The more closely you can pinpoint the melting range of the metal you are welding, the easier it will be to weld.
Aluminum vs. Stainless Steel
To those used to welding with stainless steel, welding with aluminum can pose a challenge. Aluminum welding wire needs a lot of current to start the arc, but the wire melts very quickly once the arc is started.
Feeding aluminum welding wire during gas-metal-arc-welding (GMAW) poses a challenge because it needs a fast wire speed, but is much softer than stainless steel wire and thus tends to tangle at the drive roll. Argon is the most common shielding gas used for welding aluminum because of its good cleaning action and penetration profile, and it can help you overcome these obstacles.
Getting the Setting Right
Machine settings that work for other wires may not be suitable for aluminum, which can in fact, be damaged by equipment that has been set up for steel wire. Use drive rolls that have been specifically designed for aluminum, and set the tension so that it delivers an even wire feed rate. Too much tension will deform the wire, causing rough, erratic feeding. If there’s not enough tension, uneven feeding will result.
Try to use aluminum wire for welding that is 1/16 of an inch in diameter. The larger the diameter, the easier it will feed. The best way to feed soft aluminum wire long distances is to use the push-pull method, which uses an enclosed wire-feed cabinet to protect the wire.
The push comes from the variable speed, constant torque motor in the cabinet, which helps to push and guide the wire through the gun at a constant speed and force. The pulls comes from the high torque motor in the welding gun, which pulls the wire through, while keeping the wire feed speed and arc length consistent. Plastic or Teflon liners also help keep the wire feed smooth.
Ask the Experts
The Welding Warehouse, Inc. stocks a wide variety of welding materials. We are also proud to stock PACWELD, our own, in-house brand of welding rods and wires. Visit us online at weldingwarehouseinc.com to find out more, or stop in to see us personally.