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Tank tumbling

Discussion in 'Tanks, Valves & Bands' started by Bigd2722, Jan 21, 2016.

  1. Bigd2722

    Bigd2722 Solo Diver

    # of Dives: 500 - 999
    Location: Winter Park, fl
    458
    90
    Last year someone posted on here in favor of dry tumbling. There was a general outpouring of "no way" "this is crazy" etc.

    After thinking about for several months, I have to ask: Why not?

    Does anyone have any real experience with it?
     
  2. Littlerayray

    Littlerayray Regular of the Pub

    # of Dives: 100 - 199
    Location: Cornwall, Ontario, Canada
    780
    295
    My lds sand blasts the inside of our tanks they can target the rust and not remove unnecessary metal
     
  3. Peter69_56

    Peter69_56 Divemaster

    # of Dives: 500 - 999
    Location: Australia
    1,537
    631
    Depends on the material you use to tumble with. It can be very abrasive and thus remove a lot of metal if the tank is in bad condition, or remove very little if the tank is in good condition. The medium I use takes virtually no material but just polishes it as I ensure my tanks do not get water in them in the first place. I do wet tumble only and thats because I am tumbling during oxygen cleaning so using a strong detergent. The tumbling is to remove the oil interacting within the pores of the metal at the surface.

    All my air is double filtered to prevent water ingress while filling.

    Important for you to always blow out the valve before filling. So many LDS just hook up to a tank which has been exposed to salt/fresh water in the valve. When they begin filling that small amount of water immediately enters the tank. I always give the valve a quick on/off to clear the valve mouth prior to fill.
     
  4. NAM001

    NAM001 Contributor

    # of Dives: 500 - 999
    Location: the moon
    5,002
    1,314
    You are not tumbling to take out pits. You are doing it to basically remove the surface stain or flash rusting that is present and the layer of hydrocarbon residue on the walls. media with simple green and pure water is prefect. I often just use a whip to do the job.
     
  5. Peter69_56

    Peter69_56 Divemaster

    # of Dives: 500 - 999
    Location: Australia
    1,537
    631
    Granted, normally polishing the tank not cleaning it to remove pits, however if there is significant rust/rubbish in the tank a more abrasive medium may be required. Also as you say a whip can clean it up. I don't own a whip, but nor do I intend on letting my tanks get so bad as to require significant cleanup by abrasive medium or a whip. For 95% of the tanks one would expect "You are doing it to basically remove the surface stain or flash rusting that is present and the layer of hydrocarbon residue on the walls"
     
  6. DA Aquamaster

    DA Aquamaster Directional Toast ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: NC
    11,518
    1,713
    A few thoughts:

    1. A major concern with dry tumbling is that it causes more wear in the media, but that's questionable as to get the same effect in the tank you have to wet tumble longer than you have to dry tumble.

    2. A second concern that I have heard is that dry tumbling can leave a coat of dust electrostatically adhered to the tank wall that is very hard to remove. I've never encountered that problem, and any dust that is left in a tank after a normal rinse is readily removed with a 15 minute wet tumble with an O2 cleaner and some freshly washed media or glass beads. Maybe that's what some people consider "hard to remove".

    3. You can wet or dry tumble a steel tank for weeks and not get any appreciable thinning of the tank walls.

    4. Aluminum tanks are more sensitive to excessive tumbling, and as the material is softer, you don't need as much tumbling - an hour or two should do it.

    5. You also need to take greater care in the selection of the media used in an aluminum tank. If you selected a very aggressive media that you'd use on a heavily rusted steel tank, you'll leave the surface of an aluminum tank much rougher. Wet tumbling with ceramic cylindrical pellets will leave the interior of the tank smooth and polished.
     
  7. Bigd2722

    Bigd2722 Solo Diver

    # of Dives: 500 - 999
    Location: Winter Park, fl
    458
    90
    What are the conditions or circumstances that would cause you to tumble an aluminum tank? I'm asking because I only own steel tanks and don't really know much about aluminum
     
  8. DA Aquamaster

    DA Aquamaster Directional Toast ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: NC
    11,518
    1,713
    There are two circumstances:

    1. Signs of dirt or corrosion in the tank - not just dark stains on the walls or bottom, but some sign of build up and/or anything that might be hiding corrosion on the wall of the tank.

    2. O2 cleaning the tank, where I'll tumble the tank briefly (15 minutes) with Blue Gold or Simple Green Crystal, along with washed media to help remove any surface contaminants.
     
  9. Littlerayray

    Littlerayray Regular of the Pub

    # of Dives: 100 - 199
    Location: Cornwall, Ontario, Canada
    780
    295
    Aluminum tanks do oxide it is a white flaky substance and I know for a fact salt water is not the main cause since the tanks I looked at were rentals that have only seen freshwater
     
  10. Doc Harry

    Doc Harry Solo Diver

    # of Dives: 500 - 999
    Location: Appalachia
    3,603
    825
    I dry tumble steel and aluminum for 5-15 minutes to remove light rust, then wash, rinse, dry and inspect.

    If I need O2 clean, then I wash with Blue Gold or Simple Green Crystal and rinse with distilled H20
     

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