Can You Fix a MIG Weld with a TIG Weld?

Summary

Yes, it is possible to fix a MIG weld with a TIG weld. TIG welding can be used to clean up and improve the appearance of a MIG weld, or to make repairs to a MIG weld that is not up to par. This comprehensive guide provides advanced hands-on details and technical specifications for effectively fixing a MIG weld using the TIG welding process.

Preparation

can you fix a mig weld with a tig weldImage source: Mig weld example

Before attempting to fix a MIG weld with a TIG weld, it is crucial to properly prepare the weldment. This may involve:

  1. Grinding or Sanding: Grind or sand down the MIG weld to remove any excess weld material or contaminants. This will create a clean, even surface for the TIG weld.
  2. Cleaning: Clean the weldment with a wire brush or solvent to remove any oil, grease, or rust. Ensuring a clean surface is essential for a high-quality TIG weld.
  3. Degreasing: Thoroughly degrease the weldment using a suitable solvent or degreasing agent. Any residual oils or contaminants can interfere with the TIG welding process and lead to poor weld quality.
  4. Preheating: In some cases, preheating the weldment may be necessary to ensure proper heat distribution and prevent distortion during the TIG welding process.

TIG Welding Technique

When TIG welding to fix a MIG weld, it is crucial to use the correct technique to achieve a high-quality weld. This includes:

  1. Electrode Position: Maintain a stable and consistent electrode position throughout the welding process. This ensures even heat distribution and a smooth, uniform weld bead.
  2. Travel Speed: Use the correct travel speed to match the thickness of the material and the heat input required. Excessive travel speed can lead to incomplete fusion, while too slow a speed can cause excessive weld buildup.
  3. Heat Input: Apply the correct amount of heat to the weldment. Insufficient heat can result in poor fusion, while excessive heat can lead to distortion or burn-through.
  4. Filler Material: Use the appropriate filler material for the base metal composition. This ensures compatibility and optimal weld properties.
  5. Weld Puddle Control: Maintain a clean, stable weld puddle throughout the welding process. This helps to prevent inclusions, porosity, and other weld defects.

Filler Material Selection

When fixing a MIG weld with a TIG weld, it is essential to use the correct filler material. In general, the filler material should have a similar composition to the parent metal. For example:

  • For a stainless steel MIG weld, use a stainless steel filler material for the TIG weld.
  • For an aluminum MIG weld, use an aluminum-based filler material for the TIG weld.
  • For a mild steel MIG weld, use a mild steel filler material for the TIG weld.

Choosing the appropriate filler material ensures compatibility and helps to maintain the desired mechanical and metallurgical properties of the weldment.

Weld Settings

The weld settings for TIG welding are different from those used for MIG welding. When TIG welding to fix a MIG weld, it is important to use the correct:

  1. Amperage: Adjust the welding current to the appropriate level based on the thickness of the material and the filler material being used.
  2. Tungsten Size: Select the appropriate tungsten electrode size to match the welding current and provide the desired heat input.
  3. Shielding Gas Flow Rate: Ensure the shielding gas flow rate is sufficient to protect the weld pool and prevent contamination.

These settings will vary depending on the specific application and should be carefully adjusted to achieve the desired weld quality.

Safety Precautions

When TIG welding to fix a MIG weld, it is crucial to take the necessary safety precautions to protect yourself and those around you. This includes:

  1. Personal Protective Equipment (PPE): Wear a welding helmet, gloves, and a welding jacket to protect against UV radiation, sparks, and hot metal.
  2. Ventilation: Ensure the work area is well-ventilated to prevent the buildup of fumes and gases.
  3. Fire Safety: Keep flammable materials away from the welding area and have a fire extinguisher readily available.
  4. Electrical Safety: Properly ground the welding equipment and ensure all electrical connections are secure and in good condition.
  5. Ergonomics: Maintain a comfortable and ergonomic welding position to prevent fatigue and strain.

By following these safety guidelines, you can minimize the risks associated with TIG welding and ensure a safe and successful weld repair.

Step-by-Step Guide to Fixing a MIG Weld with a TIG Weld

  1. Prepare the Weldment: Grind or sand down the MIG weld to remove any excess weld material or contaminants. Clean the weldment with a wire brush or solvent to remove any oil, grease, or rust.
  2. Set Up the TIG Welder: Set up the TIG welder with the correct amperage, tungsten size, and shielding gas flow rate. Choose the correct filler material based on the composition of the parent metal.
  3. TIG Weld the Repair: TIG weld the repair using the correct technique, maintaining a stable electrode position, using the correct travel speed, and applying the correct amount of heat. Use the correct filler material and maintain a clean weld puddle.
  4. Inspect the Weld: Carefully inspect the TIG weld to ensure it is of high quality and meets the required specifications. Check for any defects, such as porosity, lack of fusion, or excessive weld reinforcement.

By following these steps and applying the advanced techniques and technical specifications outlined in this guide, you can effectively fix a MIG weld using the TIG welding process.

References

  1. Can TIG welder repair or fix a not so good looking MIG weld?
  2. Fixing mig welds with tig. – Weld Talk Message Boards
  3. Neatening mig welds with tig