Hello Bill,
You would benefit from a good basic welding course. You could learn about the different types of arc characteristics that wire welders can produce among other things, as well as, safety.Once a bottle is filled with a particular gas or mixture, nothing else should ever be used in the bottle. Bottles are designed for safety in some cases. In other words, a helium bottle is threaded differently than an 02 bottle so the regulator will not interchange. C2H2 (Acetylene) bottles have low temp safety plugs built in to release gas in a fire. They also are filled with "pith" or "fullers earth", substances that absorb acetone so the C2H2 can be stabilized at pressures over 15# per square inch. Here are some guidelines for shielding gas selection (mixtures)for wire welding with MIG/MAG process.
Aluminum: #1. 100% Ar- Up to 1" material thickness. Best metal transfer and arc stability with least spatter.
#2. 35%Ar/65%He- 1" to 3" material thickness. Higher heat input than pure Ar. Better fusion with 5xxx series AL and AL/Mg alloys.
#3. 25%AR/75%He- 3"+ material thickness. Highest heat input/least porosity. Carbon Steel:
#1. 95%Ar/3.5% O2- Regardless of material thickness. Improved arc stability; more fluid and controllable puddle. Good bead contour, minimal undercut, high travel speed.
#2. 90%Ar/10%Co2- low cost manual welding, high speed robotic welders. Low alloy steel: 98%Ar/2%O2- good notch toughness with minimal undercut.
Other mixtures of various composition are required for stainless steel, magnesium, etc. You can buy your own bottle to avoid lease charges or daily rental fees. You are probably going to pay for a cleaning and annealing once a year. Yes, the gas house is obligated to fill those bottles if your certification papers are presented to them. (comes from the bottle manufacturer with the bottle.) If I can be of further assistance, you may contact me by e-mail or thru our site at>Link
HTH Steve
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