Tools & Fabrication - Straight CO2 for mig?

Bought a mig and came with big bottle of straight co2. Use it or get the argon/co2 mix? The guy was telling me it works the same. Don't want to fight with the weld from the start if the co2 is not optimum.

The welds with argon mix will look much better.

It depends what you are trying to weld. If its sheetmetal get the argon/c02 mix. The straight C02 will burn hotter so if its sheetmetal it will make it even easier to burn through. If its thicker metal you will get more penetration with straight c02, but the welds won`t look quite as pretty.

Basically welding brackets, exhaust tubing(which is thin walled). We'll see how it goes. Good to know co2 is better for penetration. Thanks.

Each bottle blend effects the weld differently. When I welded for a living we did mostly heavier stuff and I always used the 75/25 and it always worked well. I'm pretty sure at the exhaust shops and stuff they use a different blend, thinner wire, and they can lay down fat/wide beads on thin exhaust pipe because the penetration is shallow with their setup.

it all depends on which wire you are using

for example if you are using a stainless steel solid core wire ,tri-mix is recomended.