Tank Scouring/Tumbling/Washing

[alphakry]

thanks guys. any suggestions on tumbling media? i can't seem to find a good source of proper media - with the closest i've found being a bit pricey at $5 per lb from North East Scuba Supply

Aluminum Oxide Tumbling Chips - Per Pound

any other media out there that people are using safely and reliably? I have about 50 tanks I need to tumble clean due to being left open to the elements for far too long

 

[JamesBon92007]

I have about 50 tanks I need to tumble clean due to being left open to the elements for far too long

50 tanks eh? And I thought I had a bunch.

I just got four back from being hydroed and at least three of them have flash rust that they didn't have when I took them in. One looks like it will probably need to be tumbled so please be sure and post what you find out about tumbling media. Recently I read about using stainless steel chips and maybe it was this thread but it didn't sound conclusive.

After doing the hydro the hydro guy just stood them in a row with a hose going to each tank which I assume was just ordinary compressed air. I'm going to try the boiling water after I whip these tanks. I am not comfortable with just whipping and vacuuming and blowing them out--I want to rinse them too. And when I do blow them out I like to use dry, filtered air from a scuba tank.

I finally got to see the hydro test setup and thought that was pretty cool. This time I took them directly to the fire extinguisher place instead of going through a dive shop. The guy didn't even charge me!!! He said since I picked them up on a Saturday there would be no charge. I have three more that need to get tested so it will be interesting to see if he charges me next time. He told me he had a bunch of old steel 72s that didn't pass hydro and the owner never picked them up. I should have asked for some of the boots. They are getting hard to find. No explanation about why the tanks didn't pass but he suspected some kind of "environment" issue (excessive heat, overfilling for cave fills, etc).

 

[guruboy]

Should have taken the 72's for scrap

 

[JamesBon92007]

Should have taken the 72's for scrap

The valves might be worth a few bucks too. The cheapest one I see on eBay right now is $20 + $8 shipping. I'd pay up to $10 for a good, used boot.

 

[alphakry]

looks like i've found an option on Amazon:

12 to 40 Grit Blasting Media

seems like this may be similar size to the course grains that NE Scuba sells... but much cheaper! Anyone have experience with blasting media or similar... should that size grit do it?

 

[JamesBon92007]

I've done a little rock tumbling in the past and at the rock store they sold me varying grades of media. It worked great on rocks but I have no idea if the same stuff would work on steel tanks.

What is everyone using to plug the hole while tumbling? 3/4" PVC plug or something?

 

[tbone1004]

I've done a little rock tumbling in the past and at the rock store they sold me varying grades of media. It worked great on rocks but I have no idea if the same stuff would work on steel tanks.

What is everyone using to plug the hole while tumbling? 3/4" PVC plug or something?

go to dive shop and ask for the tank plugs that come with the tanks when they ship. they usually have them

 

[Pao]

There are a lot of tumbling media available on Amazon:
https://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias=industrial&field-keywords=tumbling+media
Which one to get?

 

[nadwidny]

looks like i've found an option on Amazon:

12 to 40 Grit Blasting Media

seems like this may be similar size to the course grains that NE Scuba sells... but much cheaper! Anyone have experience with blasting media or similar... should that size grit do it?

A coarse grit for sandblasting runs around 16-30 so that would be about the same as that. I don't think grit comes much coarser than 12 mesh.

 

[alphakry]

There are a lot of tumbling media available on Amazon:
https://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias=industrial&field-keywords=tumbling+media
Which one to get?

I'm not sure i'd trust a lot of those. Some of the top rated ones are large sharp stainless steel chunks - which I fear could do quite a bit more damage then you'd want on a compressed air cylinder. Not to mention the cost per pound is much much higher then the industry standard of aluminum oxide. You need about 30-35 lbs.

What is everyone using to plug the hole while tumbling? 3/4" PVC plug or something?

on my tumbler, the drill spins the tank from a neck sanding adapter that screws into the threads themselves so it's closed off that way, but a 3/4 thread cap would do, as would the suggestion to find caps from new tanks at your local shop. i'm not quite sure i trust the method of spinning from the neck threads, as it may put too much stress on this sensitive area but i'm just keeping the drill speed on low to hopefully mitigate that.

A coarse grit for sandblasting runs around 16-30 so that would be about the same as that. I don't think grit comes much coarser than 12 mesh.