Shielding gas is the consumable that nobody tracks closely. The wire spool runs out and you notice. The tips wear and you replace them. But the gas just flows, and unless the regulator reads empty, nobody thinks about how much is being used or what it costs. In most shops, shielding gas is 10 to 25 percent of total welding consumable cost, and a significant portion is wasted through excessive flow rates, leaks, and poor torch setups.
This guide covers the actual cost of shielding gas in MIG and TIG welding, explains why the flow rate your welder is running is probably too high, breaks down the economics of cylinders vs bulk supply, and shows how gas lenses can cut consumption by 30 percent or more.
Flow Rate: Why More Gas Is Not Better Protection
The standard flow rate for GMAW in a shop environment is 25 to 35 CFH. Most welders set it higher because they believe more gas means better shielding. It does not. Above the optimal flow rate, the gas stream becomes turbulent, pulling ambient air into the shielding envelope and actually making coverage worse.
For a standard 5/8" MIG nozzle with 75/25 argon/CO2, the turbulent threshold is around 40 to 45 CFH. Above that, the gas column breaks up. The welder sees porosity and turns the gas up even higher, which makes the turbulence worse. It is a vicious cycle.
The correct approach is to set the flow rate to the minimum that produces clean welds, then add 5 CFH as a margin. In a shop with no drafts, that is typically 25 to 30 CFH for MIG and 15 to 20 CFH for TIG. In a drafty environment, you need windscreens, not more flow.
A simple test: weld a bead at 25 CFH and examine it. If there is no porosity, the flow rate is adequate. Most welders who do this test are surprised to find that 25 CFH works perfectly.
MIG/TIG Gas Consumption Estimator
Estimate shielding gas consumption for MIG and TIG welding. Calculate cylinder life, cost per shift, and bulk vs cylinder savings based on flow rate, arc-on time, and pre/post flow waste.
Pre-Flow and Post-Flow: The Gas You Never See
Every trigger pull wastes gas in pre-flow and post-flow. At 35 CFH, each trigger pull wastes about 0.015 to 0.030 cubic feet. In tack welding with 100+ trigger pulls per hour, the waste can equal 1.5 to 3 CFH of continuous flow.
TIG welding has a more significant post-flow because the tungsten needs gas coverage while it cools. At 20 CFH, a 10-second post-flow uses 0.055 cubic feet per stop. A TIG welder making 30 stops per hour wastes 1.65 cubic feet per hour in post-flow alone.
The solution is to minimize unnecessary trigger pulls. Instead of individual tacks, run continuous stitches. Plan the weld sequence to minimize interruptions.
Gas surge on startup is another waste source. When the solenoid opens, the initial burst can be 2 to 3 times the set flow rate. A gas surge limiter ($30 to $50) smooths the startup burst and saves 5 to 10 percent of total consumption over a shift of tack welding.
Cylinder vs Bulk: When to Make the Switch
A standard cylinder holds about 300 cubic feet. At $30 to $50 per cylinder plus rental, the effective cost is $0.10 to $0.20 per cubic foot. At 30 CFH and 50% arc-on factor, a cylinder lasts about 20 hours of shift time.
Bulk supply costs $0.03 to $0.08 per cubic foot with a monthly tank rental of $50 to $150. For a shop with 3 or more welders consuming 5+ cylinders per week, bulk supply cuts gas cost by 40 to 60 percent.
The hidden cost of cylinders is handling. Each change takes 10 to 15 minutes of a welder's time. For a 5-welder shop, cylinder changes consume 2 to 3 hours per week. At $60/hour burdened rate, that is $6,000 to $9,000 per year in handling cost alone.
Microbulk is a middle option: smaller tanks refilled by delivery truck. Gas cost is between cylinder and bulk pricing. For a 2 to 4 welder shop, microbulk is often the sweet spot.
Cylinder: $0.10 – $0.20/ft³
Microbulk: $0.05 – $0.12/ft³
Bulk: $0.03 – $0.08/ft³
Break-even for bulk: typically 5+ cylinders/week
Break-even for microbulk: typically 2–3 cylinders/week
MIG/TIG Gas Consumption Estimator
Estimate shielding gas consumption for MIG and TIG welding. Calculate cylinder life, cost per shift, and bulk vs cylinder savings based on flow rate, arc-on time, and pre/post flow waste.
Gas Lens for TIG: Better Coverage With Less Gas
A gas lens replaces the standard TIG collet body with a fine mesh screen that distributes gas evenly across the full cup diameter. The result is a wide, laminar flow column that provides uniform coverage from the tungsten to beyond the edge of the weld pool. You can reduce flow rate by 20 to 30 percent and still get better coverage than a standard setup at higher flow.
Better coverage means less oxidation on stainless and titanium, which reduces post-weld cleaning. Laminar flow also allows longer tungsten stickout for access in tight joints. On stainless steel, a gas lens at 15 CFH produces cleaner welds than a standard setup at 25 CFH.
Gas lens kits cost $15 to $40. The screens need replacement every 20 to 40 hours as spatter clogs the mesh. At $3 to $5 per screen and 30 hours of life, the screen cost is about $0.15 per hour. The gas saving at 10 CFH less flow is about $1.50 per hour. The gas lens pays for itself many times over.