14 Tig Welding Aluminum Tips for Higher Weld Quality

Fantastic advice that will help your welders a lot with Tig welding aluminum

Related reading:
Tig Welding Aluminum Tips That Will Help You Tremendously
21 Tig Welding Tips That You Need to Keep in Mind

1. Clean the aluminum off using a wire brush or a scotch brite pad. Use a brand-new brush. And for the best results, use a stainless wire brush. Don’t use the stainless steel brush on anything but aluminum. The same goes for the scotch brite pad, not used on anything but the aluminum. A contaminated brush can make an aluminum weld considerably weaker.

2. Basically, there are 3 brushes – one for steel, one for stainless and the other is for aluminum. Never ever mix them up.

3. Get as much practice as possible. Aluminum, indeed, takes a while to get a feel for.

4. If you suspend your plates off the table, it sure will make it easier to get full penetration. Try putting blocks underneath your plates, leaving one inch of the plate hanging over on each side of the joint.

While suspending the plates off the table does help with full penetration, it also makes it much easier to blow holes. Practically, you really need have the skill to manipulate the metal well enough to avert from blowing a hole in your work-piece and generate the full penetration condition at the same time.

5. Aluminum requires lots of heat to weld. For example, 1/8” aluminum open corner joint asks for a machine setting of around 130 amps using AC current. The pedal should be ¾ of the way down during your welding. Zero to ½ pedal will enable you to light the arc without melting material and trail off the arc gently. Three quarter to wide open allows the operator to have amperage in reserve.

6. When using AC current on aluminum, the material will get shiny as it’s ready to accept a filler rod. If the material isn’t shiny, it won’t accept filler metal. That’s why just watch the area closely underneath the tungsten rod until you see it become shine.

For exception, DC welding aluminum with the helium shield pool doesn’t change color; it sinks.

7. When you add your rod to an aluminum weld, the pool will rise. Take this into consideration when you position the tungsten over the part; otherwise, your weld will rise up and contaminate the tungsten electrode.

8. When welding aluminum, if you do not see reinforcement above your plate, one of below two things is occurring:

• You are adding in insufficient rod

• The material is gotten too hot, and your weld has sunk. This is called burn-through.

9. Rod to torch angle is very important. Heat will reflect off your part and melt the rod if you aren’t aware of it. Just slide rod in under heat. Rod needs pushing into the pool, but not drawing in by the arc heat; or else, you won’t achieve uniformity. This applies to any process that you have to manually feed in a rod with your hand. If it can be avoided, rod and torch angle should never be the same.

Rod to torch angle is critical.

10. Keep the arc length as short as possible. The arc length is the distance between tungsten and work-piece. The more stable your hand is, the closer you can get. Different arc lengths can be applied for different materials.

11. Tungsten profiles would change arc characteristics:

• Long taper -> Heat is concentrated in small area.

• Decreasing taper -> Arc will spread out more.

• Round -> Heat will flare out (for AC current on aluminum).

12. The smaller the rod is, the harder it is to feed. Start welding with larger rods (3/32” or 1/8”, etc.)

13. Some alloys of aluminum do not weld or bend. Know what you’re welding. Do your homework on aluminum alloys by searching information on the Internet or the like. 2024 and 7075 aren’t weldable. 5052, 3003, 1100 are known as bendable soft alloys. 6061, 7075 will bend, but not in the tight radius. Just research out your materials.

Nice read about a new automotive welding technology that creates strong bonds between metals that are formerly ‘un-weldable’:
New Automotive Welding Technology Expected to Create Much Stronger Bond

14. When welding on aluminum casting, bear in mind those things:

• Grind off sand from the rough castings. There are available grinding wheels for 4- 1/2” and larger grinders specified for grinding aluminum.

• Dirty or oily castings need special care. If possible, you can plasma cut out a crack. This would clean out the oil in the crack. Drill holes at the ends of cracks; otherwise, they will keep happening after the repair is made.

• Clean the surface using alcohol or similar cleaner. Carefully heat the area with an oxy-acetylene torch for cooking out the oil. Go over the crack with a Tig torch with low heat. Use a small tungsten electrode. Don’t add welding rod. Every time you go over the aluminum, it should get cleaner. You will see the black discolor aluminum at first. Just weld, grind, weld, grind. After all, the aluminum will become shiny, then you can weld with the rod and larger tungsten.

• You can utilize sanding discs on aluminum for metal finish. Spray WD40 on the disc and the part to prevent it from loading up.

Above is helpful advice collected by Vietnam Manpower Service and Trading Company (VMST) - one welding manpower supplier from Vietnam. Do you have any tips to share? We are happy to hear them!