MIG Welding Shielding Gas Recommendation

[Satellite72]

As a beginner welder, I not sure exactly how much shielding gas would be suitable for one who is doing patch panels & quarter panel replacements. I know that lots of you guys do a little welding from time to time and probably have a good idea of what size bottles are just right for doing this kinda work. In other words, I'm going to have to purchase or rent a tank (hopefully purchase) and I'm wondering what size tank most of you guys are using. I figured that a 20 or 40 cubic foot would be ok, but I really don't know how long those last. Any suggestions? And are you using a 75%argon/25%CO2 mix?

 

[RustyRatRod]

75/25 is correct for MIG. I use a 55 CF tank if that helps. It's good for about 2 straight hours of welding. Generally, one last me a year or more.

 

[BeastlyBirdie]

Get a number 3 bottle, if you're 'buying' it. It's like toilet paper, you're going to need it. Even though the cost is a bit more, I use tractor supply, because I can get gas at 7 pm on a Saturday. The larger the bottle, the cheaper per cuft.

 

[SwedCharger67]

I bought my MIG/MAG welder last winter, never welded before.
Fixed all rust on my 67 Charger. I had to replace the floor at front passenger side, some minor around front window, some minor in the doors. Major replacement of sheet metal around rear window, quarter on one side and in front of the rear wheel on one side. Some around the trunk lid and in the lid itself. After that I've done some welding of other bits and pieces, and I still have some gas in the bottle. The bottle is fairly small, cannot remember volume right now but I can find out. On the floor, the bottle is about the same height as my knee cap...I decided to buy my bottle, it's the 75/25 mixed gas.
Welding is fun!

 

[Propwash]

Dial in your left gauge to 25 and 30 cubic foot-hours with trigger engaged...Should get you in the ball park. Like mentioned 72/25 (Argon/CO2) mix. I go with a 80# bottle...lasts a while. Obviously depends on use. Be sure to always turn off the valve for the tank when done welding. Don't rely on the stop in the Welder to contain the gas. Good way to slowly drain your bottle. Happy welding

 

[Satellite72]

Thanks Guys. I'm really excited about getting started on the welding portions of the project. I had planned on getting a welder last year, but that got delayed until this year due to other parts of the car needing attention.... all I like now is the gas and I'm ready to go!

 

[Meep-Meep]

The 25% CO2 provides a hotter weld and that is good for the smaller MIG welders. However, that mix does not work with a TIG - just throwing it out there.

 

[Pistol Pete]

Dial in your left gauge to 25 and 30 cubic foot-hours with trigger engaged...Should get you in the ball park. Like mentioned 72/25 (Argon/CO2) mix. I go with a 80# bottle...lasts a while. Obviously depends on use. Be sure to always turn off the valve for the tank when done welding. Don't rely on the stop in the Welder to contain the gas. Good way to slowly drain your bottle. Happy welding

And it's a good idea to back out the regulator screw everytime as well.

 

[roadrunnerman]

I bought my 75/25 gas from our local supply store and got a 5 yr contract with it so if i run out of gas all i have to do is just pay for the cost of refilling. The tank i got is about 5 ft tall. So far i've welded my crossmember, floor pans, small patches and still have more then enuf to weld some 1/4's on and trunk panels, plus repair my rear window corners.

 

[Pistol Pete]

Another tip: Be careful not to set the shielding gas cfm too high. In this case more is not better as too high a flow rate can actually pull air into the backside of the weld due to the venturi effect.