Reasons to Use C25 Shielding Gas When MIG Welding Mild Steel

The most commonly used shielding gas for home and hobby MIG welding is C25 (75% argon gas and 25% carbon dioxide). It's not the cheapest gas mixes but it is well liked because it gives the person MIG welding at home a nice balance between cost and quality of the finished weld. C25 is a good multipurpose gas mixture that is a desirable balance between the very narrow weld profile produced when welding with 100% argon and the volatility of welding with 100% carbon dioxide.

C25 shielding gas is a gas blend, one of several that we carry at Eureka Oxygen. It is available in the smaller gas cylinder sizes, perfect when you're doing the odd or occasional weld around the home or ranch. Beginner welders using MIG welders utilize their 120-volt circuit.

Argon is an inert gas and much less reactive than carbon dioxide. It provides a cleaner arc start and a smother melt of the welding wire into the base metals, as well as working well at lower voltages. This means it is better for thinner mild steel and low carbon metal gauges.

The argon in the C25 gas mix stabilizes the carbon dioxide and results in a nice balanced weld. ​The surface profile of the finished weld tends to be flatter and neater. With the correct weld settings, C25 produces little weld spatter. Cleaning up after welding mild steel or low carbon steel is minimal and easy.

Reasons to MIG Weld with 100% Carbon Dioxide Gas

When cost is an issue and the weld doesn't have to be the best looking then MIG welding with pure CO2 is a good option. 100% carbon dioxide is widely available and tends to be the cheapest gas to purchase. Carbon Dioxide isn't an inert gas like argon although it is commonly used as a shielding gas in MIG welding. It is a more reactive gas with the electrical arc and produces a 'hotter' arc than the C25 mix. The electrical arc when welding with carbon dioxide gas is less stable. It crackles and pops, resulting in more spatter, and more clean up of the finished weld is needed.
Carbon dioxide ideally requires higher amperage out of the MIG welder to work well. On a low amperage, the weld pool is too cool and results in low metal penetration, making it a poor choice when welding thinner metal gauges at low amps. C25 shielding gas is a much better choice for gauges under 20 gauge. The experts at Eureka Oxygen would be happy to help with solutions for your welding project needs. Give us a call today!