Tank Tumbling Help

[tbone1004]

That i guess would work but few have the assetts to do it that way, especially when the deed is done after the next full fill anyway.

vacuum is how the bottles are cleaned out for medical O2 and I believe aviators O2 at the big fill stations.

Vacuum pump from Harbor Freight-$90
Fill whip adapter from NESS-$40
1/4" NPT air hose-$20 since it's low pressure?

If you do a lot of tanks and are paranoid, probably worth the $150 to vacuum them out. For me? probably not.

 

[fmerkel]

if it's minor rust, i'd use a whip before I tumble

Where to get a whip, particularly for HP narrow neck tank?

Edit- found that link to northeastscubasupply. Does the SS end brush and whip fit into the narrow neck of HP tanks?
I got a brush setup from PSI-PCI that uses a SS end brush and some aluminum oxide impregnated pad that goes in a slot in the rod. The SS brush is too large to fit in the HP neck and the pad needs a bit trimmed off to fit. I think it still works because you can tilt it around.

Anyone got any feedback on NESS whip vs. the aluminum oxide impregnated pad?
How long do those whips last?

 

[tbone1004]

Where to get a whip, particularly for HP narrow neck tank.

more aggressive
Tank Whip - Standard Length
less aggressive
Quick Whip - $48.00 : PSI Cylinders, Professional Scuba Inspectors

 

[JamesBon92007]

Get some tumbling media. For steel, that's aluminum oxide chips. This media lasts about three days past "forever," and will leave a uniform grey matte finish (not a shiny one). I have never seen a steel tank shiny inside, but aluminum will be shiny after being tumbled with the right (ceramic) media. Simple Green is a common household cleaner. You want the kind without added scent, which is called Crystal Simple Green. You can also get Global cleaner from, say, NESS, but Crystal Simple Green is probably less expensive.

If you have a clean tank hydroed, it should take 30-60 minutes to clean it up using the right media. If it's got more rust, you will have to tumble longer. Open it up, pour out the media, look inside, refill, retumble, repeat until cleaned up. After a while you'll get tired of that and just guess high on how long to tumble (some pretty rusty ones I have tumbled for 4-6 hours). After that, there will be lots of dust, rust, and steel particles, and the tank must be rinsed. If if will be used in oxygen service (including partial pressure blending) it must be O2-cleaned. In both cases, a gallon of rust inhibitor will last you a Long Time. If you follow the directions, using it should not allow flash rust to re-form in the time it takes to dry the tank using forced hot air or very dry (that is, breathing) air.

Don't forget to clean and rebuild the valve.

NESS's tumbling page is here: Tank Cleaning

Thanks (to everyone) for all of the specific instructions! I've heard of Simple Green but in my experience when a product has been around a long time they come out with different versions so I just wanted to be sure.

I've done a little rock tumbling--are any of the lapidary tumbling products of any use for tanks?

I made a whip (a few years ago) which is merely two lengths of steel cable about seven inches long each, attached to a 1/2" steel rod with wire and epoxy. With this I am able to clean the sides and bottom effectively but up around the neck is more difficult. I tried making a shorter, inverted whip but even that didn't quite do the job on the one particular tank that I mentioned. It has a very cool, old Sportsways J-Valve and I may be looking for a new valve seat for this puppy if the last attempt to clean it didn't work. I won't know until I finally get the tank clean enough because it's the only tank I have that it fits on (1/2" threads). After whipping I have a length of poly tubing attached to a vacuum cleaner that I use to suck out all the dust that floating around which makes it easy to see my progress. I have been rinsing with boiling water (thanks to tips I found here on SB) and drying with air from a scuba tank. This seems to work quite well to prevent flash rust. I then put a few hundred psi in it, empty it, and take another look. So far so good. The guy that tumbled my old 72 that is shiny inside was pretty neurotic but no longer owns the dive shop otherwise I'd probably just take it to him. But it's always good to know how to do all of this stuff yourself--I like to KNOW the condition of my equipment, not just take someone else's word for it.

I also have a small 1800 psi CO2 tank that I'm playing with but so far fate has not dropped a suitable valve in my lap. It is 1/2" tapered thread and I'm not willing to spend $50-$60 for an old valve that might need to be rebuilt. It looks pretty good inside but I have not had it hydroed yet. It's hard to imagine that it would not pass.

 

[tbone1004]

@JamesBon92007 @herman can probably help you with that valve part.

the rock tumbling stuff is probably fine, but you likely don't have enough of it. It takes a LOT since you have to fill it over halfway to get both crowns cleaned

 

[JamesBon92007]

Anyone used a BBQ rotisserie?

 

[zider]

Anyone used a BBQ rotisserie?

That would have to be an awfully powerful rotisserie to turn a heavy steel tank. Below is a photo of the frankenstein tumbler I built from a scrap treadmill. The original build did not have a larger pulley and could not turn a HP130 filled with media. It definitely takes some torque to spin these big boys.

 

[tbone1004]

Anyone used a BBQ rotisserie?

definitely not enough power to direct drive, and not enough speed to use a pulley. You can get .5-1hp motors for cheap from various sources. The Treadmill designs are pretty good though. If you have a treadmill already you can get creative and build a rack that goes on top of the treadmill and tumbles that way. It's removable and with the variable speed of the treadmill you can get really good rpm control

 

[JamesBon92007]

Some people down the street are moving and have some exercise equipment out on the curb so I think I'll go take a look

Yea, after I thought about it I realized that by the time I geared down the rotisserie for enough power it would probably be turning at about 1/5 rpm.

 

[TrimixToo]

I want to see pics and a good description!

I'm not going to get to pics any sooner than the weekend or next week. It's a single-place tumbler. It came with media, a 5-gallon pail of accessories, and bottles marked with mixing instructions for the cleaners the prior owner used, all of which were a godsend at the time when I was getting started. It has a 2-speed washing machine motor (always run on its high speed) and a pully drive on a frame made of 2x4's with a plywood top. The top is slotted for the large pulley that drafts the single driven shaft. The steel rollers are encased in rubber hoses. I have a steel frame for it that I have yet to make the motor mount for or skin with plate so the shafts can be mounted in the new sealed bearing blocks that are waiting for them.

These are really not hard to make. Find the rollers and hose first. Size the pulleys according to motor RPM. Think about the distance between the rollers if you want to do pony and argon bottles, or make up a receiver for the small tanks that has the OD of the big tanks.