Tank Tumbling - Cleaner/Rust Inhibitors?

[dlearyous]

I'm working on cleaning out the tanks I received when purchasing a dive shop that have had a bit of problem with rust due to a broken PMV.

The tanks I am focusing on cleaning now are around 25-30 steel 12L/200Bar tanks from various manufacturers. Both long 12's and short 12's that have been hydro tested ranging from a couple months ago to a couple years ago. The rust ranges from flash rust to flush rust that needs to be removed to expose suspected pitting. We need to clean them to be able to asses the condition to see which tanks are feasible to go through the labor to put them back into service again.

I read an article by GMC that suggests their 'Cleaning Solution' and then their 'Rust Inhibitor'. My main problem now is that I would like to start tumbling the tanks asap but it will take at least a week to two weeks to get the Cleaning Solution and Rust Inhibitor out to the island.

What can be used in place of Cleaning Solution and Rust Inhibitor? I have heard that Simple Green and BlueGold do the same things but they will also have to be ordered which could take one to two weeks shipping time. Suggestions as to what I can use that will do the same job?

I have also done some reading about using Phosphoric Acid as a rust inhibitor but am questioning if I will even be able to find it on the island. I am also curious if Phosphoric Acid is a suitable solution? We have tried to find it for the past two days and havent had any luck.

This is my first time tumbling tanks myself so any and all information is more than appreciated.

 

[KD8NPB]

For my tumbing at the shop, I use about 26 lbs of media, 1 gallon of water, plus about 1 tsp of Dawn dish soap.

I rinse with hot water, then transition to cold water after about 5 minutes (hot water will remove the soap better), then blow the tank down with compressed air. Sometimes I get flash rust, sometimes I don't. If I do, I whip it out quickly.

We don't do nitrox, so oxygen cleanliness isn't a huge concern, but with that being said, I still try to keep things as clean as I can.

 

[OkByMe]

If you can find a product called "naval jelly" you will have your acid. Loctite rust remover is the same. I mix a whole 16oz bottle in a gal of water. put it all in the tank. Be sure your media will not be harmed by the acid. I use stainless chips and balls. You can recover the acid and use it again. Tumble with baking soda to neutralized the acid, then Dawn soap is good. I use the exhaust of a large shop vac narrowed down to a hose that will go into the tank neck and bottom out, dry upside down. The shop vac heats up a little bit so make shure you can spill some of the air to not overheat it. You can get some good smell back if you rinse out all the soap, all the soap, ALL the SOAP and pour in some lemon juice extract and swish it around with a little water, rinse and dry. The acid in the extract will retard flash rust until you get some dry air in the tank soon. Vinegar will help remove rust too, but will turn the color of the steel.

 

[dlearyous]

I've heard about using Dawn a few times now. Going to check on the USAFB if I can find any there! I'll look into the other suggestions as solutions for the future. Right now I just need to get my tanks back into duty!

 

[halocline]

I'm no expert on this, but I would be pretty cautious about any chemical used on the inside of the tank. I've had good luck just physically removing rust via tumbling, washing with hot water under pressure, and using dry scuba air from another tank to quickly dry the interior out. I have never once found any flash rust in my LP72s, one of which was fairly covered with rust when I bought it, since I did this four years ago or so.