Hydro on older tank

[guruboy]

So in this kind of situation, is the tank passing the second hydro a valid test? Or, asked another way, if a tank fails hydro, should it always fail hydro?

I was asking on a different thread with Luis, but wanted to post here since this thread is exactly my situation.

 

[NAM001]

I asked some time back what round out was. Got the answer and wondered. If you took a full tank to the shop would that minimise the effect of what rounding out the tank is supposed to prevent????? This discussion is of interest to me as i have some friends that use the older tanks.

 

[guruboy]

I am just guessing, but I think it should have a similar effect though not to the same extent. Assuming a full LP72 at +10%, you are looking at 2475psi. The round-out procedure is 85-90% of test pressure (3750psi). So still a 1000psi difference. Probably also depends on how fast the tank contracts after you release the pressure.