Aluminum Etc.: Use 4043 for GTAW and 5356 for GMAW

A simple standard has helped Gina Cutts make the best filler metal choice for aluminum GTAW and GMAW. Getty Images

You don’t need to be a metallurgist to choose the right aluminum filler metal for your application. There’s no need to go down the rabbit hole of aluminum filler metal schedules or know the mineral content, cracking potential, shear strength, or temperature effects.

I try to keep it simple for both myself and my students. We use 4043 with GTAW and 5356 for GMAW. This simple system works for most of my projects. A good rule of thumb to remember is 4043 is too soft to work its way through a GMAW spool gun, making 5356 the obvious choice for its feedability.

I had never been taught this nor was it ever mentioned to me at any previous jobs. I realized all the options only after I started ordering consumables and had to educate myself quickly. Like most people, I work within time and budget constraints.

For the most part, 4043 is a very forgiving filler metal and has a nice fluid appearance when used with GTAW. It is fairly easy to use and provides appropriate strength for groove welds. Again, 4043 will not feed through a spool gun when using GMAW.

5356 has superior strength for fillet welds compared to 4043 and will color-match after anodizing. It can be used with GMAW because it is stiffer than 4043 and will feed through a spool gun.

I would love to try the various aluminum filler metals available for comparison, but it is not feasible. Standardizing my shop to 4043 and 5356 has saved us time and money.