O2-Safe Rust Inhibitor for Steel Tanks

[Michael Guerrero]

So I'm planning on tumbling and cleaning my OMS/Faber LP85s. I've been looking at using rust inhibitor, but I don't really want to spend the $50+ and shipping to get a gallon of Compound O (Diethanolamine/DEA/DEOA).

Looking for alternatives, I came across Evapo-Rust and also Cocamide DEA.

Anyone used any of these chemicals as a rust inhibitor for steel tanks being exposed to pure O2?

Thanks,
Mike

 

[Wookie]

If you don't want to spend $50, I guess my suggestion of Blue-Gold wouldn't be well received at all.

 

[grf88]

See post #34 on this page:
Supplies for O2 cleaning a steel tank?
There are other posts in that thread that may be of help.

 

[grf88]

This was posted on another board a number of years ago and is what I use. It was posted by a Kenny P.

"Here is what we use. This is pasted from an e-mail I sent to some guys on another list, in 2003.

Sent: Thursday, July 31, 2003 9:16 PM
Subject: O2 Cylinder Cleaning


Start with 85% Phosphoric Acid. This can be purchased from an industrial chemical supplier.
In a 5 gal. pail add 533 ounces water and slowly add 107 ounces 85% acid, stir well. This is the basic mix at 20%. Everything else is made from this mixture. For rough, scaly steel tanks cut this mixture 2 parts water to 1 part 20% acid. Fill tank and tumble or roll in floor 1/2 hour to 1 hour. Drain and wash with hot water ASAP. Hit it for several mins. with a cylinder of nitrogen gas as soon as the hot water is poured of. The nitrogen is key to preventing flash rust due to an atmosphere with no oxidizing agent. NOTE: Run the hot water in long enough to heat the steel good and hot to the touch, this will help the nitrogen dry the tank fast. You can also make a 4 to 1 mixture from the 20% for mildly rusted tanks, use the same procedure as above. Tumble or roll on floor etc. If further rust removal is required fill with mixture again and go another 1/2 hour and repeat process. The flash rust mixture is made with 8 parts water to 1 part 20% acid. It is the one I use the most. Use the same procedure with it as the others with the exception, it does not have to be washed. Repeat DO NOT rinse after the 8 to 1. Just drain and dry with a tank dryer as normal. I did this with my O2 bottles and 2 and 3 years later they still look like new. The were manufactured in 1974 Pressed Steel 71.2 cu.ft. steel tanks.

Kenny P"

 

[Michael Guerrero]

If you don't want to spend $50, I guess my suggestion of Blue-Gold wouldn't be well received at all.

Does blue-gold inhibit rust? I already have Crystal Simple Green for the detergent.

 

[JS1scuba]

Is there a particular reason you are planning to tumble a Faber 85 ? I have some Fabers dating back to 1995 and never have needed any kind of destructive cleaning.

The only time a cylinder may need tumbling is if a certified cylinder inspector believes it is warranted.

Faber cylinders during manufacturing, after annealing, cold draw, forming, and tempering are subjected to a final internal and external shot blasting. This process creates a uniform surface on the cylinder material. The final finishing of the cylinders include both an external and internal process. Externally the cylinder receives three coatings, zinc spray, epoxy paint, and polyurethane final coating. Internally the cylinder receives a phosphatized hardening treatment to resist corrosion. If your cylinder does NOT have any flaking rust but only some flash rust, tumbling with corrosive material can damage the hardening treatment and render the cylinder more subject to future corrosion.

In close to 30 years I have NEVER "tumbled" a Faber cylinder. If you are just looking at preparing the cylinders for oxygen service, standard cleaning and drying methods work best. We use Crystal Simple Green in a 1-500 solution.

Cheers

 

[Michael Guerrero]

Tumbled them with pee gravel and CSG for 1.5 hrs, no significant change, though these tanks are not bad inside at all, just a touch of flash rust in spots. Not sure the cause of the other "patterns" on the surface, but they don't seem to be rust and there is no depth to them.

Now tumbling for 30 min using evapo-rust, diluted solution. Cold water rinse and drying to follow per the Global handbook.

 

[Michael Guerrero]

Second tank is sparkly now.

 

[rjack321]

In close to 30 years I have NEVER "tumbled" a Faber cylinder. If you are just looking at preparing the cylinders for oxygen service, standard cleaning and drying methods work best. We use Crystal Simple Green in a 1-500 solution.

I've had to tumble many Faber's filled on California boats - to get rid of rust patches where its impossible to verify depth with the rust still in there. Since the OP is in Cali I can only assume he's gotten a wet fill or two.

 

[Michael Guerrero]

Although I have been on Marrissa and Waterhorse charters, I don't think these tanks saw action in SoCal. Fills on lakes in AZ and AR though, and in FL near the water. Whatever the cause, the pee gravel and evapo-rust did a nice job. It is light yellow, looks similar in color to the Compound O from Global, though I know that doesn't mean it's the same thing.

Anyway, I guess we'll see if I die.