Sheild gas thoughts?

[KubotainNH]

I'll be buying an i-Mig 140 soon, mainly for sheet metal work. I've used a cheap flux core welder for a few years and also have a 220v stick welder, I'm looking forward to working with a MIG. Any suggestions on the shield gas? Tank renting or buying, which gas is best for the buck etc. Again, mostly car cage sheet metal. I plan on getting the flux core drive wheel for when it's windy. I don't have a nice shop like some folks....yet. Thanks and Happy New Year!

 

[RNeumann]

For the homeowner and hobbyist the (edit: 2 gas is what I have) gas is good. I (and most hobbyists) weld every so often and the bottle will last a long time. Not worth saving a few bucks on gas and then be limited to material type unless you have a major production facility that could save some real money by having dedicated gas. Have fun with it!!

I looked at my bottle and it is 2 gas. Sorry for the confusion.

 

[Shield Arc]

For sheet metal welding I would use C25 gas. 75% argon, and 25% C02. For structural welding I would use 100% C02.
My local welding supply told me if you rent bottles for 2-years, you might as well buy them.

 

[KubotainNH]

Good info, what exactly is 3 gas? Argon, C02 and something else? A quick search shows the 3rd as helium. Is that an even mix?

I see HF sells a small tank for $100 plus I could probably use a coupon on it. Some people mentioned having issues with getting those ones filled though. When it's time I'll talk to the local welding shop to see what the scoop is.

 

[Shield Arc]

Good info, what exactly is 3 gas? Argon, C02 and something else? A quick search shows the 3rd as helium. Is that an even mix?

Generally that is used for stainless steel Mig welding.

 

[Big Barn]

Tri mix formulations depend upon your supplier.

Locally, I deal with Air Liquide. ALMIGTM is a tri-mix gas containing 91%Argon-5%CO2 and 4%Oxygen. Because of its high argon content it tends to penetrate less making it an excellent choice when welding thin gauge material such as auto bodies. Which would be ideal for what you intend to weld. IMHO of course.

Terry

 

[Fallon]

I bought my tank after researching & calculating lease vs. Buy. Tanks need a hydro test every 7 years, which costs $25. Generally you hand in your old tank & get another tank back full. You still own a tank, but what tank that's changes. I've had my tank filled & returned occasionally too though.

I hear some places don't like customer owned tanks & will not fill them or not fill them without ownership documentation. Haven't ran into that or any issues showing up with just a tank & no paperwork myself at the couple local welding shops I use here in Colorado. They are more mom & pop types though. Big guys like Airgas might be more picky.

You don't get hit with hydro test charges if you lease, but $25 every 7 years is a lot cheaper than a $10-30 annual lease.

I just upgraded from my 150cf? tank to a 250cf? tank if I recall. Cost $70 & apparently happens a few times a day at my local welding shop with people needing more capacity or more portability.

 

[RNeumann]

I would have bet money I have a 3 gas mix. But after reading this article it may be 2 gas. I'll have to check tomorrow. Get the bottle from your local supplier. They will be a good resource with buy vs rent, size etc.

MIG Welding FAQs

 

[Birdhunter1]

I use Hobart .030 ER70S-6 wire and the 25% CO2/75% Argon in my Everlast 140 mig. The thinnest I've welded was 18 gauge, if I was going for car body work I might try the .025 wire but then again may just try it with my current .030 wire.

I like my current setup for what I use it for which is 1/4" and under, I use my stick machine on thicker stuff.

 

[yomax4]

I'm not a big fan of the 3 gas mix containing O2. No need to add oxidants to your welds. It's an old mix that was sold to achieve a near spray transfer with less voltage and it works well for the smaller machines. If you want high Argon you could just go with 90/10 and have favorable results. 75/25 is certainly adequate for most all short arc welding but if you are buying an inverter welder, It would be in your best interest to at least try straight CO2. Most new inverters run CO2 pretty well with minimal spatter and 1/2 the cost of an argon mix and the gas lasts 2x longer. If you don't like what you get switch back. You can rent a 5# co2 tank for a trial for less than $20.