I have tanks that have bene in continuous use since the mid 1960's, so 9 or 10 hydro stamps on the shoulder. I have seen welding tanks from the ninteen teens with 17 or 18 stamps on the shoulder.
Personally, I appreciate the (few) test facilties that think ahead, use smaller stamps and space them close together in neat lines as in the long term it allows for a lot more stamps.
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My favorite hydro test experience was with an airforce butter bar in charge of the base rec center's, scuba equipment. He was afraid soemone may steel a tank, so he stamped "USAF" in the side walls of all of them - which of course caused them all to be failed at hydro due to the damage in the sidewalls of the tanks. But hey...nobody stole them.
Personally, I appreciate the (few) test facilties that think ahead, use smaller stamps and space them close together in neat lines as in the long term it allows for a lot more stamps.
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My favorite hydro test experience was with an airforce butter bar in charge of the base rec center's, scuba equipment. He was afraid soemone may steel a tank, so he stamped "USAF" in the side walls of all of them - which of course caused them all to be failed at hydro due to the damage in the sidewalls of the tanks. But hey...nobody stole them.