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Tig Welding Aluminum
For Best Aluminum Tig Welding Results use a pure tungsten, AWS-Class EWP
Thin sheet metals are easily welded with the pulsing feature of an industrial TIG welding machine
Why Tig welding aluminum?
Welding aluminum is done using two preferred methods, both of which employ inert gases, pure argon, or a mix of argon with helium. Any contamination of these gases causes oxidation of the weld
Tig welding can be used on a variety of metals, but it's most commonly used on aluminum -- especially with small thickness metals.
Techniques other than Tig welding are able to join aluminum, but Tig welding is the most advantageous for a number of reasons. Since aluminum is used in a number of industries, particularly automotive and aerospace, its popularity is at an all time high. Due to its strength and the the clean, attractive finish of the work, Tig welding is widely used. Hobbyists find Tig to be a very useful welding technique in a number of aluminum applications.
Veteran welders call the aluminum tig welding process heliarc welding (a trademark of Linde). Like many known trade marks the name became generic for TIG welding.
Today, TIG and MIG welding are the two recommended options for welding aluminum. The TIG (tungsten-inert-gas) process uses a hand torch with a non-consumable tungsten or tungsten alloy electrode to strike an arc.
Pure argon and/or helium, both non-flammable inert gases, provide the shield around the weld to prevent weld contamination from oxides and hydrogen absorption. A filler rod of aluminum is fed into the molten weld, wherever filler is necessary.
High frequency alternating current, the preferred electrical source for manual welding is controlled by either a torch trigger or foot controlled rheostat. An alternating current gives the arc a cleaning action and divides the heat evenly between the tungsten electrode and the weld pool. TIG is slower than MIG welding, but it allows for more welder manipulation without the fixtures for faster automated production.
Learning Tig Welding Aluminum
There’s no substitute for practice. Use a welding a torch and weld rod.
Learning aluminum Tig welding
Most state funded technical schools and junior colleges have welding programs. Search your local technical school's catalog for aluminum welding courses to see what is available to you. some courses that can teach you aluminum TIG welding can be taken at nights or on weekends. (Note: the information on this site is not instruction and should not be taken as such. Seek professional training to safely work with welding and aluminum).
Aluminum is different than other metals - and that complicates the welding process
Aluminum has characteristics that make welding it different than welding steel.
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First, it weighs a third steel.
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Secondly, aluminum's thermal conductivity is six times greater than that of steel.
Rapid heat transfer makes the weld solidify faster than steel. Steel melts at 2,800 Fahrenheit, while pure aluminum melts at 1,220 Fahrenheit. Surface oxides -- which are one of aluminum's natural barriers against corrosion -- melt at higher temperatures, starting around 3,725 degrees. That's nearly a thousand degrees higher than the melting point of steel.
Aluminum Welding Preparation and Pre-Cleaning - Remove surface oxides!
If the oxides aren't removed prior to welding, sound metal fusion doesn't happen. This is why weld preparation and cleanliness are more important for aluminum welding than they are for steel.
Clean these oils and greases with an non-chlorinated solvent such as toulene. Don't use Chlorinated solvents, as they can emit toxic fumes while you're welding. Be certain your welding area is well ventilated. Use the solvent and a stainless steel wire brush.
Heated aluminum doesn't color
Aluminum doesn’t show color when it's heated, which makes the lightweight metal tricky to weld. The thing to look for is the silvery "sheen" generated by the blue hue of the arc - that's molten metal.
When the weight of the puddle exceeds the surface tension of the molten metal the spot sags, leaving a hole in the weld surface.
Aluminum oxide abrasives are common
Aluminum oxides are extremely hard; they're also heavier than aluminum. They can damage or destroy milling cutters if the oxides are in welds where finish machining has been done.
Another thing that makes welding aluminum different than steel is aluminum's affinity for hydrogen gas. It pulls in the gas when molten and emits it when it's solid.
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