Welding and Safety Information

Common Gases Used in Welding

Argon-CO₂

 75% / 25%

• Commonly Called: C-25
• Used in: MIG (GMAW) welding
• Benefits: Balance of penetration, arc stability, and less spatter.  The addition of argon smooths the welding arc and improves     its stability, while CO₂ contributes to penetration.
• Best for: General steel fabrication. Results in a more controlled and consistent weld, which is particularly beneficial for beginner and intermediate welders
  

Pure Argon (Ar)

• Used in: Most commonly used in TIG (GTAW) welding industry for ferrous and non-ferrous metal such as stainless, copper and titanium alloys.
• Benefits: Provides a stable arc, smooth welds, and low spatter.
• Best for: Aluminum, stainless steel, and non-ferrous metals.
• Spray Transfer Mode: Used when welding aluminum with a spool gun or MIG (GMAW) to help prevent oxidation while using a push-technique.

Tri-Mixture (90% Helium / 7.5% Argon / 2.5% CO₂)

• Commonly Called: Tri-Mix
• Used In: MIG welding of austenitic stainless steels like 304, 316.
• Benefits: Excellent arc stability and weld control
• Low spatter and clean welds
• Promotes good penetration and travel speed
• Helps retain corrosion resistance in stainless steel by minimizing oxidation

Carbon Dioxide (CO₂)

• Used in: MIG welding (often alone or in blends)
• Benefits: Deep penetration and good for thicker, dirtier material. CO₂ creates a high-energy arc that results in deeper penetration compared to other shielding gases.
• Best for: outdoor welding compared to other gases. Since it is denser than air, it is less likely to be blown away by wind, making it more reliable for outdoor construction, shipbuilding, and other exposed environments.  CO₂ produces deeper weld penetration, which is especially useful when welding thicker materials or when strength is a key consideration.
• Downside: More spatter and less control than blended with argon. High-heat can, burn through materials. Welds made with pure CO₂ can have a rougher, less smooth finish, with more oxidation and a higher chance of porosity 

Helium (He)

• Used in: TIG and MIG
• Benefits: Hotter arc for faster welds and deeper penetration.
• Best for: Thick materials, stainless steel, and aluminum. For aluminum materials thicker than 1/4" (6 mm), using a mix of argon and helium (commonly 75% argon, 25% helium) allows for a more stable, hotter arc to quickly melt thicker sections and increasing travel time. Aluminum is prone to oxidation, which can lead to porosity in the weld. The hotter arc from the helium helps burn off oxide layers quickly, resulting in higher-quality welds.
• Downside: Significantly more expensive gas.

Oxygen (O₂) – In Small Amounts

• Most Common Blend: 98% Argon, 2 % Oxygen
• Used in: MIG (GMAW) welding (added to blends)
• Benefits: Adding small amounts of oxygen (typically 1–5%) to argon significantly improves arc stability and weld puddle fluidity. The presence of oxygen helps ionize the arc more efficiently, resulting in a smoother, more consistent weld. This enhanced arc stability is particularly beneficial when welding carbon steel and stainless steel, where a controlled, steady arc is critical for producing high-quality results.
• Best for: Carbon and stainless steels. Faster Welding Speed: The higher arc temperature and increased penetration make it possible to weld at faster speeds. This is particularly advantageous in high-production environments where time efficiency is critical.
• Downside: Adding too much oxygen (above 5%) can lead to oxidation problems, creating a brittle weld. Excessive oxygen can also increase spatter and make it more difficult to control the arc. Argon-oxygen mixtures are generally not used for aluminum welding, as oxygen can cause oxidation of the aluminum, resulting in poor weld quality. For aluminum, argon or argon-helium mixtures are usually preferred.

💡 Note: The exact gas mix depends on the welding process (MIG, TIG, etc.), material thickness, and desired weld quality. Always refer to welding procedure specifications (WPS) when available.