Steel 120

[ebbtide]

ive got a question about a tank a steel 120
it ran out of its hydro so i i took it into be tested for the first time the tank is 5 years old .
the feller who did the hydro said it just had to be SAND BLASTED INSIDE not i am no expert by far but i am wonderning if he might have been able to put 2 grooves in the tank witch he dident see at first and had to fail the tank, i talked to the LDS and they were very upset at the hydro dude for SAND BLASTING the tank they said something that it shulds been roled or turned ?
i mean how does 2 grooves get into the INSIDE of the tank in 5 years if it has never been opened up and a visual every year ?
i know nutthing about the prosses ide like some advice or is it just something that happens ?

 

[devjr]

Ebbtide, it takes special equipment to sandblast the inside of a tank. If it's sandblasted at all, only glass beads should be used as the media, not sand.

Normally, tanks with rust inside are partially filled with some abrasive "sand", placed on a rack with turning rollers and "tumbled" over and over, gently, for several hours.

Is this a Faber tank? Maybe the guy saw the interior's black oxide coating and thought it had to be blasted out. Anyway, there shouldn't be any grooves. That is not supposed to happen.