Key Takeaways

• Porosity is caused by gas entrapment, not arc problems—focus on shielding and cleanliness
• Diagnose in 5 minutes: check gas flow, inspect the torch, and clean your base metal
• Most fixes cost under $20 and take less than 15 minutes
• Gas lens collet bodies improve shielding coverage and reduce porosity risk
• Test on scrap before returning to production

Quick Diagnosis

What you’ll see:

• Small holes or bubbles in the weld bead (visible after cooling)
• Bead surface looks rough or pitted
• Porosity appears randomly or consistently across the weld

Likely causes (ranked by frequency):

1. Gas flow too low or regulator leaking
2. Contaminated filler wire or tungsten
3. Weak gas shielding (torch too far from work, wind, or bad gas lens)
4. Dirty base metal (rust, mill scale, oil)
5. Arc length too long or tungsten dipped in the puddle

Safety Notes

• Eye Protection: Use ANSI Z87.1-rated helmet with correct shade (typically #10–#12 for TIG). Porosity inspection requires close-up viewing—use a magnifying glass if needed.
• Ventilation: TIG produces less fume than MIG or stick, but always weld in ventilated space or use a fume extractor. Tungsten inert gas (argon) is inert but displaces oxygen—ensure adequate air circulation.
• Electrical Safety: Disconnect the welder before inspecting the torch or changing consumables.
• Compressed Gas: Argon cylinders are pressurized. Never drop or expose to heat. Check regulator connections for leaks using soapy water (never a flame).

Step-by-Step Troubleshooting

Step 1: Check Gas Flow (Free)

• Set regulator to 15–20 CFH (cubic feet per hour) for TIG.
• Listen for a steady hiss at the torch nozzle.
• If flow is weak or silent, check for kinks in the gas line or a leaking regulator.
• Why: Low gas flow leaves the weld unshielded, allowing oxygen and nitrogen to enter the puddle and form gas pockets.

Step 2: Inspect the Torch and Gas Lens (Free)

• Remove the torch from the cable and look inside the nozzle.
• Check for spatter buildup, cracks, or discoloration on the gas lens or collet body.
• If the gas lens is damaged or heavily spattered, replace it (see “Recommended Fix” below).
• Why: A damaged or dirty gas lens creates turbulence in the shielding gas stream, reducing coverage and trapping gas in the weld.

Step 3: Clean the Base Metal (Free)

• Use a wire brush, grinding wheel, or stainless steel brush to remove rust, mill scale, and oxidation.
• Wipe with a clean cloth to remove dust and oils.
• Weld within a few minutes of cleaning (oxidation returns quickly).
• Why: Contaminants on the base metal release gases when heated, which get trapped in the molten puddle.

Step 4: Test Arc Length and Technique (Free)

• Keep the tungsten 1/8″ to 3/16″ above the base metal.
• Maintain a steady, smooth arc without dipping the tungsten into the puddle.
• Avoid moving the torch too fast or too far from the work.
• Why: Long arc length weakens gas coverage. Dipping the tungsten introduces tungsten oxide and moisture, causing porosity.

Step 5: Check Filler Wire and Tungsten (Low Cost)

• Inspect the filler wire for dirt, rust, or kinks. Replace if contaminated.
• Check the tungsten for cracks, balling, or discoloration. Replace if damaged.
• Use the correct tungsten size for your amperage (typically 1/16″ to 3/32″ for most hobby/shop work).
• Why: Contaminated consumables introduce gases and oxides directly into the weld.

Fix Options (Ranked)

1. Adjustment (Free)

• Increase gas flow to 15–20 CFH.
• Clean the base metal thoroughly.
• Reduce arc length and improve torch angle.
• Best for: First-time porosity or occasional issues.

2. Consumable Replacement (~$10–$30)

• Replace the filler wire spool if old or contaminated.
• Replace the tungsten electrode if cracked or balled.
• Best for: Consistent porosity after adjustments fail.

3. Gas Lens Collet Body Replacement (~$15–$25)

• Replace the gas lens and collet body to restore shielding coverage.
• Improves gas flow pattern and reduces turbulence.
• Best for: Persistent porosity despite clean base metal and correct gas flow.

Recommended Fix (Product Section)

Why a gas lens collet body works: A gas lens is a small brass component inside the torch that organizes the shielding gas flow into a smooth, laminar stream. Over time, spatter and oxidation clog the lens, creating turbulence and weak coverage. Replacing it restores full shielding and eliminates porosity caused by weak gas coverage.

When to use it:

• After cleaning the base metal and confirming gas flow are correct, but porosity persists.
• When the old gas lens shows visible spatter, cracks, or discoloration.
• As routine maintenance every 50–100 hours of welding.

When NOT to use it:

• If gas flow is low—fix the regulator first.
• If the base metal is dirty—clean it before replacing the lens.
• If the tungsten is dipped in the puddle—improve technique first.

What to check before buying:

• Verify your torch model (WP-17, WP-18, WP-26, WP-9, WP-20, WP-25, or SR series).
• Confirm the collet size matches your tungsten diameter (typically 3/32″ for standard work).
• Check that the package includes both the gas lens and collet body (some sell lens only).
• Ensure the product is in stock and ships quickly (you’ll want to test immediately).
• Look for 4+ star reviews from verified welders.

STARTECHWELD 45V26 TIG Gas Lens 3/32” Gas Lens collet body Fit TIG WP17, WP18, WP26 (5 Pack) 45V26

• TIG Gas Lens 45V26 Tig Torch Gas Lens 3/32”
• Work With: TIG 17, 18, 26 Series Torches
• 3/32" Tungsten Electrodes Standard 10N Series Collet
• 54N Series Gas Lens Ceramic Cups Setup
• Pack of 5

Buy on Amazon

Last update on 2026-06-26 / Affiliate links / Images from Amazon Product Advertising API

Comparable Options

If you prefer a larger pack or different torch size, consider:

• 10-Pack 45V26 Collet Bodies (B07KCXHF4G): Same specs, larger quantity for shops doing frequent replacements.
• Assorted Gas Lens Kit (B081LKNHGS): Multiple sizes (45V26, 45V27, 45V43) if you run different torch models.

Common Mistakes

• Assuming porosity is an arc problem. It’s not—porosity is a gas/contamination problem. Check shielding first.
• Running gas flow too high. Above 25 CFH, excess gas creates turbulence and actually increases porosity. Stick to 15–20 CFH.
• Skipping base metal cleaning. Rust and mill scale are the #1 cause of porosity in production shops. Always clean before welding.
• Replacing the gas lens without checking the regulator. If the regulator leaks or is set too low, a new lens won’t help.
• Ignoring tungsten contamination. If the tungsten is cracked or oxidized, replace it. A bad tungsten will cause porosity no matter how clean the base metal is.

FAQ (Snippet-Optimized)

Q: What causes porosity in TIG welding? Porosity is caused by gas entrapment—usually from weak shielding (low gas flow, damaged gas lens, wind), contaminated base metal, or a dipped tungsten. Fix shielding and cleanliness first.

Q: How do I know if my gas lens is bad? Look inside the torch nozzle. If you see spatter buildup, cracks, or heavy discoloration, replace it. A clean lens should look bright and smooth.

Q: Can I fix porosity by adjusting amperage? No. Amperage doesn’t cause porosity—gas coverage and cleanliness do. Adjust gas flow, clean the base metal, and check the torch instead.

Q: How often should I replace my gas lens? Every 50–100 hours of welding, or whenever you see visible spatter or discoloration. Shops doing high-volume work replace them weekly.

Q: Will a new gas lens fix all my porosity? Only if the porosity is caused by weak shielding. If the base metal is dirty or gas flow is low, a new lens alone won’t fix it. Address all three: gas flow, cleanliness, and torch condition.

Next Steps

For more TIG troubleshooting and gear guidance, check out these related posts:

• TIG Torch Maintenance: How to Clean and Inspect Your Torch (internal link)
• Tungsten Electrode Selection Guide: Choosing the Right Type and Size (internal link)
• Argon Gas Flow Rates: What CFH Do You Really Need? (internal link)

For more welding fixes and gear options, see our full resource page: https://blog.weldsupportparts.com/links/