Quote Originally Posted by undercut View Post
Seems there must be a few different materials used in cylinders because I found one where the same cylinders sizes were a bit heavier.


I don't think I'll be doing much TIG'ing so I'm wringing my wrists over buying an inexpensive and very small 20cf tank on sale now at HF and pocket the savings to refill at expensive rates or buying a much bigger 80cf and paying 4 times the price for the cylinder but getting refills cheaper. It will really depend on much I think I will use in a year (which of course I have no idea!)

Weld time should be a simple exercise in math, right? 20 cf tank / 15 cf/hr flow rate = number of welding hours (must take into account any pre/post flow) ??
Not as much as the tanks are different materials as they may be a bit thicker with manufacturing tolerances and different manufacturers have a slightly different shape of the tank. Just like if you but a sheet of 1/4" 4x8 one sheet to the next will be a couple lbs different.

Almost all my tanks are 125s easy to move around and not real heavy. (largest I can get around here without a hassle) Most of the price to fill tanks is labor. So the price for a smaller tank is about the same for a larger. That is why a larger tank you get a better bargain. Unlike a gas station where you pay the same price whether you are filling a large or small tank.