I bought my large (Around 5' tall) tanks at a farm auction around a decade back. I hauled them to a local welding shop who explained that they were out of inspection, so I paid to have them sent out and sand blasted, painted, new valves and hydro inspected for 10 years. I took them home and scuffed them down and sprayed them plum crazy base/clear with red stencil lettering saying OXYGEN (2 of them) and Acetylene (1 tank). I've had to refill only 1 of the 2 oxygen tanks since then and the goober at the shop tried to tell me I owed rent, and that he would exchange the tank... I about lost my ****. I paid around $600 for the whole process back in the beginning after the tank serial numbers were run to verify that the tanks are not on the national list of ownership. I originally dealt with the (now retired) father, and the son had no clue of the history of this transaction. I argued until he called his dad and his dad explained that he remembered me and that they are MY tanks... Now I have fear of taking my tanks in since it will potentially be a battle to make it understood that I own and paid for these tanks to be put back into service. Rent... I am not paying no stinking rent!