Able to stop rust inside a tank??

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9supratt4

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Location
NJ
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25 - 49
I have 2 Steel 100's that I just had VIP'd. The LDS said they have some small rust inside, but nothing to worry about at this point. If I get them tumbled, will that stop the rust, as long as no moisture gets inside??
 
Nothing,just prevent moisture to get in.
i.e.use a good compressor/filling station.
 
So the answer is yes...you can stop the rust from spreading if you do not allow mositure inside...correct??

Also, when storing a tank for a few months until next dive season, how much air should be inside??
 
flash rust is a fact of life with steel tanks, you will always get a little.
Leave about 25 PSI in the tank. Just enough to keep atmospheric air out.
 
flash rust is a fact of life with steel tanks, you will always get a little..

:no: it's not.All 30 of my tanks are steel and completely rust free.
 
So the answer is yes...you can stop the rust from spreading if you do not allow mositure inside...correct??

Also, when storing a tank for a few months until next dive season, how much air should be inside??

Yes the answer is yes.:D be sure to leave some air in any tank you store,any pressure above atmospheric will do,or even store it completly full.It'll be ready when you need it and air does not go bad.
Last weekend I used a tank I forgot about for 7 years.:wink:
 
Wow, leave 25 PSI in a tank. That valve holds 3500 psi of air in the tank, so how is moisture getting past the valve. The dive shop that you are getting your air from is not draining his compressor every 20 minutes and that builds up in the tank same as when he does not change his filters oil gets through and lays in the bottom of your tank that is where that black stain on the bottom of the tank came from.
Flash rust is when you take your tank in to get hydro no mater how fast he empty's out the tank and turns it over to dry you will get the flash rust. So when you get home you whip the tank and blow it out with clean air.
Ed
 
I just bought these tanks used....so I really can't say how they were treated before.
 
I just bought these tanks used....so I really can't say how they were treated before.

Since VIP seems to be mandatory in the US,get it done.
Otherwise drain them, remove the valves, and have a look with a light on a string.
 
i love the anwsers you get on here.

for the record
1) if they have moisture in the bank system it will show up in the tank. how bad it is depends on the moisture content.

2) leave air in the tank. just leave 500psi or a full tank. not in between. this is because if there were a fire and you were not around to get to the tanks, the overpressure plug should go before your tank explodes, or the tank will fail from heat damage before any thing else bad happens.

3) if you drain your tank empty to look inside after a vip, prepare to have it vip'ed again. if there is no air in the tank the shop will have to look inside it, so i suggest not taking the valve off yourself.

4) wipping the tank or tumbeling it will remove the rust as long as it is not extensive. if it is you will need a tumbeling expiditor to help the process along and some bottom brushes to clean the bottom of the tank. when you tumble use a joy and water solution with the media to help suspend the rust so it comes out eaiser when you drain the media.

5) after you rinse the tank when you are done tumbeling there is a flash rust preventer you can use to help stop the rust from forming. you can also use compressed air to blow out the water or buy a tank dryer stand and heat gun to help dry the tank in an effort to help with the rust.

6) if the tanks are new, and the bank system where you get your tanks filled have a low moisture content you should not have a problem with rust in the tank. since you bought them used it is hare to tell without looking in them myself how bad it is. you can whip them first and stick the end of a reg hose with the end cut off inside the tank to blow out the dust, take a look and see if that did the job. if not they should be tumbled and you will have to deal with the possibility of flash rust again

as for using a steel tank that has sat for more than a year, i would not advise. it is possiable that the oxygen content could be low enough to cause hypoxia in some cases and that would not be good. when in doubt take it to have it looked at by the pros, and dont allways heed the advise you find on here. there are plenty of knowlgeable people on here, but there are plenty who dont have a clue to some things.
 

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