Troubleshooting Weld Quality: How Gas Flow and Purity Impact Results

When your welds aren’t turning out the way they should, the problem isn’t always technique or equipment, it might be your gas. Shielding gas quality and flow rate play a major role in producing clean, consistent welds. Even small variations can cause porosity, spatter, or weak welds. In this guide, we’ll break down how gas issues affect weld quality and how you can troubleshoot them effectively.

1. Why Shielding Gas Matters

Shielding gas protects the molten weld pool from oxygen, nitrogen, and other atmospheric contaminants. Without proper shielding, you’ll see defects such as:

• Porosity: Tiny holes caused by trapped gases in the weld metal

• Excess spatter: Resulting from unstable arcs or contamination

• Weak welds or poor fusion: Often due to improper gas coverage

Using the right gas mixture for your application, and ensuring it’s pure, helps produce smooth, strong welds with minimal cleanup.

2. Common Gas-Related Welding Problems

Here are a few of the most frequent issues welders face related to gas:

Problem	Likely Cause	Solution
Porosity	Moisture or oxygen contamination in gas	Check gas purity and fittings for leaks
Inconsistent arc	Fluctuating gas flow	Inspect regulator and flowmeter
Excess spatter	Incorrect gas mixture or pressure	Verify correct gas blend for material
Oxidized welds	Low flow rate or drafts at weld site	Increase shielding or use wind screens

3. Gas Flow Rate: Getting It Just Right

Flow rate has a direct impact on weld quality. Too low, and air contaminates the weld pool. Too high, and turbulence draws air into the shielding area.

Pro tips:

• Typical MIG welding flow rates range from 20–30 CFH.

• TIG welding often needs slightly less, around 15–20 CFH.

• Use a flowmeter, not just a regulator, for accurate readings.

• Keep hoses and fittings tight to prevent leaks or pressure drops.

4. The Role of Gas Purity

Even the best equipment can’t make up for poor gas quality. Contaminants like moisture, oxygen, or hydrocarbons in your shielding gas can lead to brittle welds or discoloration.

At Simcoe Gases, we provide high-purity welding gases that meet or exceed industry standards. Every cylinder and bulk system is tested and maintained to ensure consistent gas quality, so you can focus on performance, not problems.

5. Preventative Maintenance Tips

To minimize gas-related weld defects:

• Inspect hoses and fittings weekly for leaks or wear

• Keep regulators and flowmeters clean and calibrated

• Store cylinders upright in a dry, well-ventilated area

• Use dedicated gas lines for each type of gas to avoid cross-contamination

• Schedule regular deliveries or cylinder exchanges from a trusted supplier

6. Partner with Simcoe Gases for Reliable Welding Performance

When you rely on quality gases, your welds reflect it. Simcoe Gases supplies a full range of industrial and specialty welding gases, bulk and cylinder delivery, and on-site gas systems. Our expert team helps you choose the right gas blend and flow setup for your specific welding process, so every weld meets your standards.

Contact Simcoe Gases today to discuss your welding gas needs or request a free consultation.