Gas type

[MUDBUG]

I've been using a C02/Argon mix with my MM 175 and have reached the end of my first bottle. It has worked well so far using it on 1/8", 3/16" and 1/4" mild steel. I was wondering if I should try straight C02 or go with the mixture? What are the advantages of straight C02?
Thanks!

[MAC702]

I prefer CO2 for general purpose. Slightly better penetration and much cheaper while lasting longer at the same time. It will give a bit more spatter, especially at higher settings, but it's still a clean process and the little spatter comes off easily.

The C-25 mix is much better for thin stuff, less than 18-gauge, but you can still weld 22/24-ga. with CO2 if you're good.

I used a MM175 as my exclusive GMAW machine for many years.

[gnm109]

It's hard to beat C02 if you are a hobby welder like me. It really gives a nice clean weld...some spatter but that can be controlled by limiting heat and keeping the tip of the torch very clean.

I can get an exchange refill 20 pound bottle (equal to 160 cu. ft of gas) for $23.00. Not bad.
Also, the bottles are smaller than the full-sized gas bottles like C25 and are easier to handle and fit to your cart.

[MUDBUG]

Sounds like C02 will work well for my purposes. I just have a small 40cf bottle with the C-25 mix. I wonder if I'll be able to exchange that for a C02 bottle or should I get another bottle for strickly C02.

[jamlit]

I agree with the above. I use CO2 for almost all my mig welding. The bottles last longer and the price is cheaper. I do allot of sheet metal work, so like MAC702 said above it takes a little change to get good welds but it not a big problem. CO2 also gets better pentetration. The only major down side to CO2 is their can be more splatter but not enough in my opinion to make a big difference. Give it a try and see what you think

[MAC702]

Since you already have the argon cylinder, try to hang on to it. It shouldn't be too expensive to get another one outright for the CO2.

[David R]

I use Co2 with my bigger machine and .045 wire. It works great. For the finer stuff with my sp100, I prefer the C/25. Co2 works, just not quite as well. Try it. You will save a BUNCH of money.

On any machine, Co2 takes 2 to 3 more volts. If you are streaching a 110 mig, increasing the voltage to make it weld with Co2 cuts down on the amps. No doubt penatration is better with the Co2.

David

David