Aluminum Welding Process (Short Guide + Parameters Settings)

Aluminum Welding

This is a short and simple Aluminum welding guide where I have explained to you the step by step Aluminum welding process along with the welding parameters settings.

I have also mentioned the recommended parameters and settings for aluminum MIG welding as well as aluminum TIG welding.

Let’s dive right into it.

(Note: Jump to step 6 for aluminum welding parameters settings).

Aluminum Welding Process (How to weld aluminum?)

Follow this 10 step aluminum welding process and parameters settings to get a perfect aluminum weld.

Let’s discuss each step one by one.

Step 1: Safety first

It is very essential to take safety measures before starting any welding procedure.

  • The fumes and gases produced during the welding work are harmful to your health.
  • Also the ultraviolet rays produced from the arc can cause injury to the eyes and skin.
  • The electric shock can even kill you.
  • Before starting the aluminum welding process, you must read and understand the manufacturer’s instructions, material safety data sheets (MSDS) as well as the employer’s safety practices must be followed.
  • During the welding of aluminum, keep your head away from the fumes.
  • Enough ventilation or exhaust should be used near the arc so that the fumes and gases escape from your breathing zone.
  • Always wear eye protection, ear protection and body protection for your safety.
  • Do not touch the live electrical parts during the welding process.

Step 2: Select joint design & fit up

It is very essential to have a correct joint design and fit up to get the strong welded joint.

  • While selecting the joint design, the parameters like degree of strength required, welding positions, metal thickness, joint accessibility, etc should be considered.
  • The basic welded joints which can be performed in aluminum welding are;
    • Butt joint, 
    • Lap joint, 
    • Corner joint, 
    • Edge joint, and 
    • Tee joint.
  • In order to set up the position of the metal pieces, the jigs & fixtures are also used during the aluminum welding process.
  • During the welding operation, the sheet metal, or any other workpiece should be tightly clamped together over its entire length.

Step 3: Choose the welding process

Aluminum MIG welding and Aluminum TIG welding are the two most popular Aluminum welding process.

Submerged metal arc welding (SMAW or stick welding) is also used for welding of aluminum, but it is used mainly for small repair jobs only.

Step 4: Determine the appropriate inert shielding gas

Shielding gases for Aluminum welding are mentioned below.

Shielding gas for Aluminum MIG welding: 
For Aluminum MIG welding, argon is suggested for thickness up to approximately ½”. 
Argon-helium mixture or pure helium may be used for welding of thicker sections. 
Pure helium is sometimes used as a shielding gas for deeper penetration work in aluminum.

Shielding gas for Aluminum TIG welding:
For Aluminum TIG welding, argon is used as a shielding gas for most applications. 
By using argon as a shielding gas, deeper penetration and clean weld can be achieved. 
25% argon and 75% helium mixture is used for material having thickness more than a half inch. 
If helium is used as a shielding gas, then it produces a hotter arc which is necessary due to high thermal conductivity of aluminum.

Step 5: Select appropriate filler metal

For aluminum welding, there are various factors responsible for selection of appropriate filler metal. 

The filler metal can range from pure aluminum to various alloys with added copper, silicon or magnesium with it.

For detailed aluminum filler material selection, you can see this chart.

Step 6: Set up aluminum welding parameters

Recommended parameters and settings for aluminum SMAW welding, aluminum TIG Welding and aluminum MIG Welding are mentioned below.

Aluminum SMAW welding parameters:

For aluminum welding using SMAW process, both direct current or alternating current welding power source can be used.

DC current uses either straight polarity (which is electrode negative) or reverse polarity (which is electrode positive).

In SMAW welding for aluminum, there are several advantages of using a DC power source.

It works well at a low current setting and ignition of arc as well as maintaining the shorter arc is easier.

Electrode: Al-43 aluminum electrode is recommended with DC polarity for SMAW welding of aluminum.

Ampere: Recommended amperage settings are given below.

Diameter3/32 × 14″⅛ × 14″5/32 × 14″
Ampere50 – 8585 – 135110 – 165

Aluminum TIG Welding parameters:

Manual aluminum TIG welding (or aluminum GTAW welding) is usually done using AC current source.

For aluminum TIG welding, a high frequency generator is used for starting the arc and maintaining the stable arc.

Electrode: Pure tungsten electrode or zirconiated tungsten electrode is recommended for aluminum TIG welding with AC current.
The tip of the tungsten electrode should be hemispherical in shape.

Aluminum TIG welding parameters depend on the plate thickness, weld position and design of the joints.

For flat position, the recommended settings for Aluminum TIG welding are given below.

Aluminum TIG welding parameters

ThicknessTungsten sizeFiller rod sizeAmpereVoltageGas cupGas flow (cfh)
1/16″1/16″ – 3/32″1/16″ – 3/32″70 – 10015⅜”20
3/32″3/32″ – 1/18″⅛”90 – 12015⅜”20
⅛”1/18″ – 5/32″⅛” – 5/32″125 – 175157/16″20
3/16″5/32″ – 3/16″5/32″ – 3/16″170 – 225157/16″ – ½”25
¼”3/16″ – ¼”3/16″220 – 27515½”30
⅜”¼”3/16″ – ¼”330 – 38015⅝”35

Aluminum MIG Welding parameters:

Aluminum MIG welding (or GMAW aluminum welding) is done using a DC reverse polarity (electrode positive).

In MIG aluminum welding, the transfer of metal from filler rod to workpiece takes place by spray transfer mode.

For flat position and argon shielding, the recommended settings for aluminum MIG welding are mentioned below.

Aluminum MIG welding parameters

ThicknessFiller wire sizeAmpereVoltageGas flow (cfh)
1/16″0.030″70 – 11015 – 2025
⅛”0.030″ – 3/64″120 – 15020 – 2430
3/16″0.035″ – 3/64″130 – 21022 – 2630 – 35
¼”3/64″ – 1/16″170 – 22524 – 2840
⅜”1/16″225 – 30026 – 2950

Step 7: Clean the base metal

  • Cleaning of the weld metal is also necessary to get the perfect strong welding.
  • Also cleaning is done to avoid the formation of oxides.
  • The aluminum surface which is to be welded should be free from grease, paint, oil, dirt, etc.
  • Steel wire brush is used to remove the burrs and oxides from the weld surface.
  • Welder should wear gloves to avoid the hand oil or dirt sticking to the welding surface.

Step 8: Preheat if applicable

  • In most of the cases, preheating is not required for welding of aluminum.
  • But in some cases, it can be helpful to reduce cracking.
  • Preheating also helps in equalizing weld penetration when welding metals of different thickness.

Step 9: Use proper aluminum welding technique

Aluminum welding technique depends on the expertise of the welder.

But there are many tips for aluminum welding that should be followed to get good aluminum weld.

  • Use jigs & fixtures to hold the workpiece rigidly.
  • The weld joints should be designed properly so that weld penetration can take place easily.
  • Proper supply of shielding gas shield should be provided to prevent the weld area from contamination.
  • For aluminum TIG welding, the filler material should be dipped in the weld puddle, but it should not drip into it.
  • The welding torch should be moved at a uniform speed to maintain uniformity in weld.
  • The torch should be held over the weld until gas stops, so that the weld area remains protected.

Step 10: Cooling and cleaning the weld

The aluminum welded joint should be cooled down slowly. If AL-43 coated electrode is used, then remove slag after welding is done.

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