Can You Weld Cast Aluminium With A MIG Welder? Answered

The answer to Can You Weld Cast Aluminum With A MIG Welder? is: Cast aluminum can be welded, but only with careful planning and execution. Utilize AC TIG welding with a clean or zirconiated tungsten electrode after cleaning the surface and preheating the material to 350-650°F (177-343°C).

Choose an appropriate filler metal, such as aluminum alloys 4043 or 5356, for best results. Cast aluminum can be successfully joined with TIG welding if a few technical and safety considerations are made.

Can You Weld Cast Aluminum With A MIG Welder??

Aluminum may be welded down to a thickness of 3 mm using the most reliable MIG machines. Using specialized MIG or TIG welders with pulse capability may be necessary to successfully weld materials thinner than 3mm.

Weld Cast Aluminum With A MIG Welder

Casting Method

The manufacturing process also affects how easily cast aluminum may be welded. Die casting, green sand casting, investment casting, and permanent mould casting are the four typical processes used to create cast aluminum.

Welding dies aluminum castings are quite challenging. This is because aluminum is pressure-injected into a steel mould that cools with water when it is die-cast. This instantly makes the casting cool.

Gases cannot escape thanks to the cast’s fast cooling. During welding, it might be challenging to deal with these air pockets.

The final three casting type’s are permanent mould casting, investment casting, & sandy casting—which can be easily welded.

These techniques produce aluminum castings that cool gradually. This is a result of the low thermal conductivity created by these castings. As a result, gasses can freely escape from the casting.

Why Weld Aluminum Cast?

Cast aluminum can be used for various things, including automobile parts and minor appliances. Knowing how to weld cast aluminum will be useful for fixing jet pumps, bolt holes, boat engine parts, etc.

Why Weld Aluminum Cast

Tips For Getting Started

Think About The Material Thickness

Aluminum can be MIG welded at thicknesses of 14 gauge and higher; the maximum thickness you can weld depends on the output capacity of your welder. If you want to MIG weld aluminum thinner than 14 gauge (.074 inch), you might need to employ pulsed MIG or AC TIG welding gear.

Keep It Clean

Aluminum must be cleaned entirely before welding, and lubricants should be removed. A stainless wire brush, either a hand brush with wire or a cup wire brush, should remove oxide after degreasing.

Keep the rpms and pressures low while using a power wire brush to avoid smearing the material’s surface, which could trap oxides and contaminants beneath it. Always clean with an aluminum-only wire brush to prevent contaminating the base material.

Pick The Proper Gas

Since aluminum is a non-ferrous metal, it needs a shielding gas made entirely of argon. Using flow rates between 20 and 30 cubic feet per hour is advised.

What Method Ought You To Employ?

The preferred mode for MIG welding aluminum is spray transfer. During this operation, the transfer of hot metal droplets from the electrode’s tip to the molten pool is remarkably seamless. The diameter of the droplets crossing the arc is smaller than that of the electrode.

The deposition rate and spray transfer efficiency are quite good, and there is no short-circuiting. Be mindful that spray transfer includes significant heat, which might result in a sizable weld pool with excellent penetration that is challenging to manage. It shouldn’t be utilized on materials thinner than 14 gauge.

Options For Gun And Wire Feeding

Before MIG welding aluminum, selecting a gun and wire feeding system is crucial. Aluminum wire is frequently fed using a push-pull method or a spool gun. Spool guns, which place a small pool of wire on a pistol-grip style gun, enhance the feeding of soft wires.

Because the wire only feeds a few inches using a spool gun, bird nesting is eliminated. A motor in the cannon pushes the wire through the liner in a push-pull system, while an engine on the feeder serves as an assist motor. This solution might be more ergonomic and user-friendly and is perfect for welding away from the power source.

The Best Metal For Filler

Know the aluminum alloy in your base material and the environments to which the completed product will be exposed. The two aluminum filler wires that are the easiest to get are ER4043 and ER5356. For advice on the best wire alloys for your application, speak with your neighborhood welding dealer or the representative for aluminum filler metal.

How To Weld Aluminum Cast?

  • For cast aluminum, preparation is equally as crucial as welding.
  • To remove grime and oil, try using acetone. To remove the oxide coating, use a stainless steel wire brush. Before welding, you can then rinse and dry.
  • The most popular methods for welding cast aluminum are TIG and MIG welding.
How To Weld Aluminum Cast

Check out their methods and advantages below.

TIG Cast Aluminum Welding

Excellent for aluminum castings is TIG welding. The oxide layer can be automatically removed. No mechanical wire feeding is required. Cast aluminum can be shielded from contamination by TIG. Here are some ideas to think about:

  • Prepare a 3/32 2% lanthanide tungsten electrode.
  • AC frequency should be set to 50 Hz.
  • Set the AC balance to 65% electrode negative to gain more penetration.
  • On cast aluminum, pure argon works best as a shielding gas.
  • If the cast aluminum is still contaminated, perform another cleaning pass and heat to 200°F.
  • Forward and backward motions should be used when welding (I suggest beginning at the borders to generate more heat).
  • Depending on the nature of the alloy, add the filler of your choice.


Did you get the answer? Can You Weld Cast Aluminum With A MIG Welder? The weldability of cast aluminum depends on the alloy components and casting process. Alloys 3XX and 1XX can be welded.

Additionally, cast aluminum produced by investment, sand, or continuous mould casting can be welded. Die castings are difficult to weld. For the convenience of TIG welding cast aluminum, I suggest it.

Frequently Asked Questions

How should cast aluminum to be best welded?

Cast aluminum should only be TIG welded with pure argon gas, never a mixture of argon and CO2, as done with MIG welding. An argon/helium mixture is advised for welders that require deeper penetration. The gas flow should be between 16 and 18 cubic feet per hour for aluminum up to half an inch thick.

Cast aluminum: Should I MIG or TIG?

A TIG torch is easier to maneuver into a confined space, making it a viable option for repair on cast aluminum components or restricted access. MIG welding, on the other side, is a good option to speed up repair because TIG welding is a slower procedure.

At what temperature can cast aluminum be joined?

Before welding, preheat. In general, preheating enhances welding performance. The typical range is 100-300C or 212-572F. Copper-containing aluminum alloys are typically welded at the higher portion of that temperature range.

Can a MIG welder cast while welding?

Cast iron can be joined using the MIG method and specialized flux-cored electrode wires, but the welded joint won’t be as robust as one made using an MMA arc. The R-Tech team advises MMA stick welding as the primary method for joining cast iron, as was already mentioned.

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