Question for the vintage masters about a 1969 tank

[r1_addict]

I have been diving for about a year and have amassed quite a bit of gear. I was happy to discover my dad's old PST 72. It has a born on date of 11/69, I have another steel 72 not quite as old I use for 100% 02 and wanted to use the vintage one as another deco bottle for a 50/50

I sent the tank out for shot blast and hydro. It looks great with a new hydro and all. Before I sent it out i noticed what appeared to be a layer of rust on the bottom. It was still there after the shot blast and hydro so I inquired. I was told it was some type of anti rust agent that can't be removed. Now I can't have it o2 cleaned so it is just a spare air tank at the moment.

The shop tells me it will put the tank at risk if I use a more aggressive means of blast. I figured aluminum oxcide would get this crap off.

Suggestions please....

 

[Wookie]

A lot of those steel 72's came with a teflon coating inside the tank. The teflon isn't a problem, but traps other things in the teflon that can be. This coating is extremely difficult to remove, but persistant tumbling can do the trick. Ask your local refurbishment facility. I know of one cylinder refurb facility (in Houston) that actually sandblasts the cylinder, then does NDT on the bottom to verify proper thickness of the steel. I'd be surprised if yo can damage a steel cylinder by tumbling it with an abrasive grit made for tumbling, unless you leave it on the tumbler for a month.

Good luck.

 

[r1_addict]

I am guessing it would be more cost effective to find one without the coating. Thanks for the validation.

 

[INFIDELxx]

You may find this thread helpful.

Vintage Double Hose • View topic - removing Vetronized interior coating from Usdivers 72 steel

 

[r1_addict]

Very cool. Mine is the "brown" coating so I was correct in assuming the aluminum oxide would work!