Tank Scouring/Tumbling/Washing

[nadwidny]

So I spent about $6 at Lowes and made two tank scrubbing whips for my steel tanks. They work OK, but there are still some small superficial rust spots inside. I'm not particularly worried about it, and they did clean up the bottoms of the insides of the tanks well.

Then I swished around some crystal simple green in hot water inside the tanks, and thoroughly flushed them out. For the first tank, I used straight hot water from the tap, and noticed that the tank felt pretty warm to the touch. I dried it with warm air and it came out looking nice inside, without flash rust.

For the second tank, I didn't use as hot water, just warm water this time, to flush out the simple green, and followed the same drying process. However, I noticed that the second tank did have some flash rust in it after drying.

I was wondering if this was the result of using warm instead of hot water when I did the rinsing.

Anyone have experience with this?

I use boiling water. Dries ++quick. No rust. Wear gloves.

 

[Michael Guerrero]

Yes, hair dryer with hose attached to push air in and hot water on the first tank = no flash rust.

Tanks have to get hundreds of degrees hot before there is any concern about affecting strength, right?

 

[tbone1004]

you aren't going to hurt them with boiling water if that is what you're concerned about

 

[WarrenZ]

Al tanks shouldn't be exposed to temps over 300f if I remember correctly. You cant get there with boiling water.

I just blast out with scuba air or if I'm paranoid I will use nitrox.

 

[Chris H]

The boiling water is a good idea. I've been using compressed nitrogen to dry my tanks. If there isn't oxygen, there shouldn't be rust either.

 

[guruboy]

I just blast out with scuba air or if I'm paranoid I will use nitrox.

Why would you use nitrox? That's higher O2 content to make rust.

Did you mean pure nitrogen?

 

[WarrenZ]

No my nitrox being hyperfiltered less chance of contaminants. I don't have nitrogen at home.

 

[guruboy]

Rust is oxidation of the steel.

So I guess the nitrox is more for cleanliness than rust prevention?

 

[WarrenZ]

Rust is oxidation of the steel.

So I guess the nitrox is more for cleanliness than rust prevention?

Thats the Idea I clean my air tanks however dont always maintain O2 Cleanliness in them, my nitrox tanks are all PP mixed and are O2 Clean.

 

[JamesBon92007]

I have a steel rod about 3 feet long to which I attached two lengths of steel cable about 10 inches long each, opposite each other. I used epoxy and #24 (I think) copper wire to attach the cables to the rod. I also have a PVC threaded, 3/4 inch adapter that the rod fits through and is slightly threaded into the tank (the threads are not the same). It stays in place well enough to protect the tank threads while using the whip. At slow speed in a VSR drill motor it will clean the bottom thoroughly and at higher speed will clean the sides.

After it's done i rinse the tank thoroughly and blow it out with compressed air and dry it in the sun upside-down.

I have only used this whip on steel tanks. Personally I would not use steel cable on aluminum, but perhaps nylon cable ties might work if they don't wear out too quickly. I arrived at the two steel cables by trying other arrangements including four cables. Two seems to be all you need.

I'd send you pictures but I'm just getting ready to leave for Playa del Carmen.

I thought I'd better add that I do NOT use compressed air from a typical, oil-filled compressor. That might introduce contaminants into the tank. I use compressed air from a scuba tank. It might also be possible to use an oil-less compressor but I would use a lot of caution doing this unless it is specifically made for breathing supplies.