Selecting a suitable welding gas cylinder are more of a logistical and physical science decision than it is guesswork. A common assumption is that bigger is better; however, when working from a ladder fixing gear, carrying a huge tank around isnt easy. The following chart show the relationship between weight, portability, and capacity for acetylene, oxygen, and shielding gases.
While you may know how to grip the torch, what about the size of cylinder? Far too many novices purchase oversized tanks only to discover they won’t fit through the door at there workshop. Green cylinders, ranging from small MC size to large K2, is used for O2 delivery. For most home shops, the T-size cylinder are great; it contains 80 cubic feet of O2. It’s not too light to be moved around shop but also won’t tip over. Fill up to about two thousand psi.
How to Choose the Right Welding Gas Cylinder
The fitting is CGA-540 which is important because it requires a right handed turn. That means tight is clockwise. Do not use oil or grease on anything near the oxygen valve! Materials will burst into flames when oxygen under pressure contact the metal thread.
Red: Acetylene cylinders are colored red and hold a porous material soaked with acetone that prevents gas from becoming unsafe at higher pressures. The key rule when using acetylene are flow rate. Never draw more than one-seventh of the cylinder capacity per hour of acetylene. Drawing gas too quickly will cause liquid acetone to travel from tank up to your regulator. Not only does this contaminate your equipment but it also poses a fire hazard in the line. With a small B-tank, the maximum safe draw would of been around five cubic feet per hour. That’s not enough to cut through thick steel.
Welding gases is used differently for TIG and MIG welding. A CGA-580 fitting is typically used for argon and a blend of argon and carbon dioxide while pure carbon dioxide use a CGA-320 fitting. The reason has to do with the common need to withdraw the CO2 as a liquid for higher flow rates. To estimate the life of your tank, don’t assume all those cubic feet will be useful. Suppliers can never get back all that leftover pressure in their tanks; plan on losing ten percent unusable gas and stay realistic regarding your budget. Depending off wind conditions, you’ll get five or six hours of welding time from a standard one hundred twenty-five cubic foot cylinder using moderate flow rates.
So how do you get your cylinder? Do you own your cylinder(s) or rent them? The initial cost of ownership appears to be higher than renting cylinders; however, if you weld frequently enough, those monthly payments begin to pile up. If you only weld occasionally (once per month), then go with exchange. Otherwise, buy outright and save yourself the continuous rental costs. In most cases this will pay off in two years for daily users.
There are strict safety rules here. Each cylinder must be chained down (to a cart or a wall). An unchained cylinder can fall over, severing its valve and turning into a missile that tears through walls. Never carry any tanks without the protection cap in place. Oxygen should never be stored within 20 feet of fuel gas unless separated by a suitable fire rated barrier.
You should know what it is. Knowing what you purchase allow you to choose the correct tool for the job. Compressed chemistry respect should be given. If in doubt, begin slowly, find out your tool’s limitations and store properly to keep working safely for years.
