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C355 (4009) Aluminum Microwire

Item#: 3H5CXH

C355 (4009) Aluminum Microwire

Item#: 3H5CXH

Premium ultra-fine welding wire for all your microscopic applications. Perfect for precision Micro TIG and Laser Welding.

C355 aluminum welding wire, as well as the variant 4009, is a versatile welding material primarily used for joining aluminum and aluminum alloys. It typically consists of approximately 90% aluminum (Al), 4% silicon (Si), 1% manganese (Mn), 1% copper (Cu), and trace amounts of other elements such as zinc (Zn) and titanium (Ti). This specific chemistry is carefully formulated to provide the wire with excellent weldability and mechanical properties making it suitable for a wide range of applications, from automotive components to aerospace structures.

The silicon content enhances the fluidity of the molten metal during welding, promoting a smoother and more stable weld bead. The manganese and copper additives contribute to the wire's strength and enables the weld to respond to heat-treating.

50 pieces of MicroWire™ in each tube

  • VCI paper for moisture control
  • Red protective tubing with resealing caps
  • Military Performance Specified foil vacuum package


  • AWS A5.10, Class R-C355.0
  • AWS A5.10, Class ER4009
  • AMS 4245
  • ISO 18273, AlSi5Cu1Mg

* Specifications may vary per heat.
Please inquire with your specification before purchasing.

Standard Welding Sizes are also available . Please contact us with your inquiry. 

    $74.00 ($1.48 per piece)

    + Free Shippingwithin the US

    *if you use more than 500 pieces annually, please contact us for OEM pricing



    HQA Wire Products strongly recommends exercising safe welding practices to protect yourself and others. Electric shock can be dangerous and can kill. Fumes and gases can be dangerous to your health. Arc rays can injure eyes and burn skin.

    Safe Welding Practice include but are not limited to:

    • Do not permit electrically live parts or electrodes to contact skin.
    • Do not allow contact with clothing or gloves if they are wet.
    • Insulate yourself from work and ground.
    • Keep fumes and gases from your breathing zone and general area.
    • Keep your head out of fumes.
    • Use enough ventilation for exhaust and arc or both.
    • Wear adequate eye, ear, and bodily protection.
    CA Prop 65

    WARNING: This product can expose you to chemicals including chromium or nickel, which are known to the State of California to cause cancer. For more information go to .

    Please see our Safety Data Sheets regarding safety practices while using this product.