Aluminum needs a lot of heat—almost twice as much as steel—to heat it up enough to form puddles.Being able to control the heat is the key to successful aluminum welding.Getty Images
If you’re working on an aluminum project and your comfort zone is steel, you’ll quickly realize that everything you know about successfully welding steel won’t work when applied to aluminum.This can be very frustrating until you understand some of the key differences between the two materials.
Aluminum needs a lot of heat—almost twice as much as steel—to heat it up enough to form puddles.It has one of the highest thermal conductivity.While aluminum can absorb a lot of heat and still remain solid, that doesn’t mean you should crank up the voltage and hope for the best results when soldering.You need to follow a set of parameters to achieve the desired effect.
An easy way to dial in the machine is to increase or decrease the voltage by a factor of 5 until you get a shiny wet puddle within three seconds.If you get a puddle in a second or two, lower the voltage by 5 until it happens within three seconds.No puddles in three seconds?Increase the voltage by 5 until you do.
At the beginning of TIG welding, you need to fully depress the pedals to generate enough heat, but when you start to fuse, you need to move the pedals halfway back.Watching your bead profile will give you a visual indication of how much pedal pressure you need.If you are using scratch welding (stick welding), you must allow the material to heat up for a while at the beginning of welding before it can successfully fuse.
When I was teaching others, I explained that they needed the lowest voltage setting in order to give them the best operating temperature.Excessive heat can cause weld cracking, oxide inclusions, heat-affected zone softening, and porosity—all of which can degrade your material and affect the quality of your weld, both structurally and visually.
With full control over heat input, you can regulate and hopefully eliminate these common problems.
WELDER, formerly Practical Welding Today, showcases the real people who make the products we use and work with every day.This magazine has served the welding community in North America for over 20 years.
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Post time: May-19-2022
