Originally Posted by swh127
They might put the tank on a scale to see how much CO2 they have added in, for charging purposes, however the place that I go to can only fill my tanks up to 3/4 lbs because they are only allowed to transfer from one tank to another. There is a firehall about 30 minutes away that can anctually fill a 5lb tank with 5lbs of CO2.
I would also disagree with your statment that a 5lb tank will weigh 5lbs. I have a brand new aluminim (i think) tank that is extremly light and a 27 year old CO2 tank that weighs itself probably 10lbs. They both will hold 5lbs of CO2 and are the same size tanks.
You misunderstood what I was trying to say. Obviously the tanks weigh differently. What they are weighing is the amount of CO2 they put IN the tank. It's done the same way with propane tanks. A five pound tank of CO2 is full when the scale indicates it has five pounds of CO2 in it. The same goes for a ten and twenty pound tank.
How they account for the weight of the tank prior to filling it, I don't know, but I do know that somehow they do, and these places have plenty of experience doing it.