Cleaning tank rust

[peterbj7]

It is unacceptable to return a tank from test (hydro or visual) without at least a few psi in it. I strongly recommend you do three things:-
*report these cowboys
*demand your mnoey back, and sue them if necessary
*publicise their name & address here and elsewhere so that while they're still in business (not for much longer I hope) discriminating divers are warned off them.

I have run these operations and I know how things should be done.

 

[peterbj7]

duplicate post.....

 

[captain]

I find most commercel hydro testers are not as concerned about a bit of flash rust as divers are. I expect it when I get tanks back and mostly don't worry about it if the tank is dry. If I want it rust free then I would clean it myself but rarely do and I have tanks that are 50 years old.

 

[captain]

It is unacceptable to return a tank from test (hydro or visual) without at least a few psi in it. I strongly recommend you do three things:-
*report these cowboys
*demand your mnoey back, and sue them if necessary
*publicise their name & address here and elsewhere so that while they're still in business (not for much longer I hope) discriminating divers are warned off them.

I have run these operations and I know how things should be done.

You expect a bit much from a commercial hydro facility. Only divers are that anal about tanks.

 

[peterbj7]

I expect that as a minimum. And I get it.

 

[oxyhacker]

Hope you used a plastic sleeve in the tank neck, to protect the threads from being battered by the spinning rod!

As a practical matter, if the rust was slight enough to be removed with a monofilament whip as you describe, then odds are pretty good it was what would be considered light flash rusting, and (much as we divers hate to see it in our tanks) perfectly legal under the CGA inspection guidelines, which is what the hydro shops go by. Many of these shops are not set up to tumble or clean tanks anyhow - that's not their job. So they are often less than sympathetic when a one or two tank customer complains, let alone demands money back or threatens to expose them to the DOT! The most this is likely to accomplish is that the hydroshop will just stop doing tanks for individuals.

Re peterbj7's comments, that a tank should never be returned from hydro without some pressure in it, this is just not true. Most hydro shops will not even replace the valve in the tank - that is not their job either! They stick a bit of tape over the opening, and that's it. Dive shops that do a "boutique" business in hydroing scuba tanks, now that's a different matter. But then they usually charge a lot more!

Running a commerical hydro shop is not a delicate business. At $10-$15 a tank you got to really move the tanks through to make a reasonable profit. Most shops do a pretty good job drying the tanks too, but there are always a few that slip by and end up with a little flash rust.

I think I may have said this before, but I always find it ironic that we divers bypass dive shops and hunt around for the cheapest possible price on hydros, then get all bent out of shape when our tanks don't get the sort of special handling we would like. I think any diver who choses to go direct to the hydro shop instead of through a dive shop should understand basic tank maintenance, and this includes dealing with flash rust.

QUOTE=Paladin954;4528254]

I got the rust out, though. I took the aluminum cleaning rod from one of my gun cleaning kits and attached lengths of "weed eater" trimmer line to it with duct tape to make a brush.[/QUOTE]

 

[Paladin]

I inserted a short piece of PVC pipe into the tank neck and taped it in place to protect the threads.

I know I'm being a bit anal about the little bit of rust that was left in the tank, but I hate rust! I've had that tank for 33 years and have been religious about keeping it pristine, inside and out. The very sight of that rust inside my little beauty nearly sent me into spasms! LOL

 

[Cave Bum]

It is unacceptable to return a tank from test (hydro or visual) without at least a few psi in it

Re peterbj7's comments, that a tank should never be returned from hydro without some pressure in it, this is just not true. Most hydro shops will not even replace the valve in the tank - that is not their job either! They stick a bit of tape over the opening, and that's it. Dive shops that do a "boutique" business in hydroing scuba tanks, now that's a different matter. But then they usually charge a lot more!

In answer to perterbj7's comment, like Vance said, your confusing a 2 part process with just what you see from dropping your tanks off at a LDS. Since you are a shop owner, you probably already know this. The LDS removes the valves does a 'pre-inspection' to be sure the tanks are okay prior to hydro, then sends them out (usually) with a piece of tape over the hole. The hydro facility, again usually, is testing far more fire extinguishers then scuba tanks. Although most 'good' hydro facilities tend to send the tanks back dry, not all do and they're not really required to. It's the LDS's job to visual and reassemble the tank and make sure it's safe to use.

Be safe and have fun in the water! Bruce

 

[peterbj7]

I have never used a tank testing facility, in Britain or Belize, that does not dry the tanks fully and put 20-30 bar of air in. Most of the people I know would reject a tank returned in any other state.

 

[DA Aquamaster]

The truth is somewhere in the middle. A visual inpsection for rust, pits, thread defects etc is required as part of the requalification process - what divers call a "hydro test" - as in fact the hydro test is only part of the requalification process.

Most hydro test facilties do the visual inspection first to ensure they are not wasting time hydro testing a tank that would be failed due to excessive rust, pits, etc, but they still have an obligation to at least take a quick peak inside at the end of the process to ensure it is dry, reasonably clean and reasonably rust free before they stamp it and certify that it can be returned to service.

In my experience, tanks come into a hydro facility with the valves on, are devalved with the valves marked and/or sorted or racked so that they find their way back to the right tank, then tested and dried then revalved but not filled. This is the same basic process for welding tanks, medical O2 tanks, CO2 tanks and scuba tanks. In some cases, a test facility may replace medical O2 valves as a separate service and/or replace the teflon washers on the valves so that they can be filled immediately after they are returned. (It is note worthy that no special O2 cleaning is involved in the hydro tesing process with medical O2 tanks and they don't seem to be exploding with any regularity. O2 tansk do not pick up muhc in the way of contaminants in service and if devalved and re-valved by the facility, they do not pick up significant contaminants during the test process. The average hydro test facility is not a clean room, but the tap water used during the test is not swimming in grease and oil either.)

The average dive shop then does their own scuba industry VIP rather than DOT VIP and fills the tank. Any tumbling is normally done by the shop before the tank goes to hydro to avoid having the hydro tester reject it due to rust. But that also leaves the possibility of some flash rust in the tank.

Some shops may devalve the tank prior to sending it out for hydro test, but that is by no means universal and is not really required. I'd argue it is also not well advised either as it greatly increases the potential for contamination during transist to, from and at the test site.