Aluminum is a popular metal used in many industries, from transportation to construction. However, welding aluminum can be challenging due to its high thermal conductivity and high coefficient of thermal expansion. Following proper techniques and using the right equipment is key to achieving strong, lasting aluminum welds. In this article, we’ll explore some of the top tips for aluminum welding using common processes like MIG, TIG, and more.

Pro Tips for Aluminum Welding

Preparation is Key  

Proper preparation is essential for quality aluminum welds. All surfaces should be cleaned of dirt, oil, paint and oxide layers using a stainless steel brush or chemical cleaner. Aluminum oxide on the surface can prevent proper fusion. Beveling edges, using joint designs that allow full penetration, and tack welding can also help improve weld access and control heat buildup.

Choose the Right Filler Wire  

Selecting the appropriate filler wire for the base aluminum alloy is critical. Match the alloy composition and mechanical properties as closely as possible. 4043 and 5356 are common filler alloys for 6061 alloy. Consider 5000 series filler for 7000 series alloy. And silicon-bronze alloys are sometimes used for better flow and wetting. Consult welding codes and a welder’s guide for best pairings.

Manage Heat Input  

Aluminum conducts heat quickly. Too much heat too fast can burn through the base metal. Use lower amperage, faster travel speed, pulsed MIG technique, and other methods to control heat input. Allow metal to cool between weld passes. Use copper backup bars to draw heat away. TIG technique offers the most heat control for thin materials.

Use the Right Gases & Settings 

100% argon shielding gas works best for aluminum. For stronger penetration, 2-5% oxygen can be added. Higher gas flow up to 25-30 CFH cleans oxides. But too much flow can blow and turbulence. Find the right balance for the welder. Higher voltage helps penetration. Adjust polarity and travel angle to control weld shape. 

Employ Push Techniques

Pushing the weld puddle gives better control and vision. Pulling can lead to lack of fusion defects. Use forehand technique with MIG torch angled 5-15 degrees. Position TIG torch behind or at 9 o’clock. FCAW guns should be held at 10-15 degrees. Strings of unmelted flux mean drag angle is too high.

Preheat When Needed  

Preheating aluminum from 200-250°F reduces cracking risks in thicker sections by slowing cooling and preventing hydrogen absorption. But too much preheat over 300°F increases distortion. Localized heating methods like laser provide optimal control. Post weld heat treatment can also increase ductility and strength.

Use Pulse When Possible

Pulse MIG with alternating high and low current allows heat control and cleaner welds. The pause lets puddle solidify between pulses, avoiding burn through. It also allows oxides to float off. Consult your welder manual for recommended pulsing parameters based on material thickness.

Clean Between Passes 

Aluminum oxide will quickly coat the weld surface as it cools. Use a stainless steel wire brush or abrasive pad to remove oxides before adding each new pass to allow proper fusion. Use wire brush after the final weld as well. Oxides trapped in the weld can lead to porosity and cracking over time.

Forging forward with nexAir Products and Expertise

nexAir welding aluminum products help your business forge forward; proper aluminum welding takes professionalism to acheive, but you can do better with Nexair aluminum welding products. Following the tips outlined above will help ensure strong, lasting welds for any aluminum application. Don’t be afraid to do some test welds on scrap to dial in your technique. 

With nexAir KnowHow  in aluminum welding, we can help maximize your benefits and reduce costs. Our extensive knowledge of aluminum alloys, joint designs, filler wires, and welding techniques equips you with cost-effective best practices for strong, seamless welds. Our hands-on training will empower you and your team with the skills to get the most out of our aluminum welding products. Partnering with Nexair gives you a true advantage with tailored insights to guarantee quality welds and foster welding success.