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Sherwood dry bleed contaminated piston

Discussion in 'Regulators' started by fmerkel, Aug 13, 2016.

  1. miguelation

    miguelation Angel Fish

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    Well, I live in South Florida, and they are very popular here, due the mold that grows here in the roof and driveways from the high humidity. They sell them cheap in Home Depot or Harbor Freight tools. Or you can keep and eye, when you see someone using one, and let them use it for a minute or two. I have been trying for over 10 years for a way to clean them. I am an engineer, so, for me it was a bucket list challenge. :)
     
  2. W W Meixner

    W W Meixner Rebreather Pilot

    # of Dives: 500 - 999
    Location: Ontario Canada
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    Folks...

    First and foremost...I don't advocate this procedure...only reporting that it works like magic...

    On the work-bench of the LDS where I had a post-retirement position for seven years...we had a closed-lid plastic tupperware container with about two inches of what the owner referred to as ''magic water''...

    We serviced a lot of old Sherwood/Aqua-lung/Dacor...and a few other...regulators for which replacement sintered filters were no longer available...including the Sherwood ''old style'' pistons with the by-pass filter...

    Using a pair of tweezers to hold the part...and for only a few seconds...the part was dipped in the ''magic water''...immediately any contamination fizzed up...contamination being salt/cylinder scale/AL cylinder oxidization dust etc...

    The fizzing would only last a couple of seconds...and then stop...when it stopped...the part was immediately removed and rinsed with fresh water...

    The parts came out shining like a new penny...and functioned perfectly...with all the contamination plugging the filter gone......

    ''Magic Water''...first word starts with an ''M''...second word starts with an ''A''...

    W...
     
    Ghetto Diver and miguelation like this.
  3. fmerkel

    fmerkel Loggerhead Turtle

    # of Dives: 1,000 - 2,499
    Location: Salish Sea (Seattle)
    1,564
    555
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    "Magic Water"....interesting.

    Think it would deal with silicone grease contamination? One of my mistakes the first time I overhauled a Sherwood was to put the piston in a small basket into the ultrasonic with the rest of the metal parts. Standard 1/2 strength vinegar solution. Piston was already WELL contaminated with salt. Ambient chamber was caked with it. I think the bleed had likely been plugged for awhile so the chamber got flooded when diving.

    Didn't know that was not proper procedure. OTOH, I think the initial problem might have been from a shop overhaul and that tech maybe didn't know either. The reg was retired/replaced when it didn't deliver sufficient air in a deep current situation. Sat in a box for years until I started doing my own regs and I thought to check that one out. Amazingly easy to work on compared to many other regs. That was when I found the ambient chamber full of salt crystals, lots of salt crystals.
     
    miguelation likes this.
  4. W W Meixner

    W W Meixner Rebreather Pilot

    # of Dives: 500 - 999
    Location: Ontario Canada
    626
    419
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    FM...

    If the little piston by-pass filter is plugged...it's likely crystalized salt...and not silicone...silicone grease and/oygen compatible lubricant...unless it's contaminated should pass through the filter...

    Our shop regs were Sherwood...I serviced them annually...using OCL...never had any issues...

    Some of the older Sherwood pistons are still available...the model with the crimped-in HP seat is not...unless you can find some ''new/old'' stock...

    Try the magic water... if the sintered filter starts to fizz...you know right away it's plugged with contaminates

    Best...

    Warren
     
    miguelation likes this.
  5. miguelation

    miguelation Angel Fish

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    I don’t think Magic Water dissolves silicone or Christo lube at all.
     
  6. W W Meixner

    W W Meixner Rebreather Pilot

    # of Dives: 500 - 999
    Location: Ontario Canada
    626
    419
    63
    M...

    You may be right...but I don't think ''lube'' unless it's contaminated with particulate matter would be the cause...the plugging has likely occurred gradually...most likely salt/cylinder scale/sand...

    Best...

    W...
     
  7. JoeFriday

    JoeFriday Photographer

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    If your friendly LDS service tech screwed it up, it is lube.
     
  8. Rusty Shackleford

    Rusty Shackleford Barracuda

    # of Dives: 500 - 999
    Location: Port Canaveral Florida
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    If it’s just salt, water should dissolve it.


    If it’s calcium or magnesium or potassium deposits, a weak acid should get it done. Have you tried white vinegar?
     
  9. Rusty Shackleford

    Rusty Shackleford Barracuda

    # of Dives: 500 - 999
    Location: Port Canaveral Florida
    411
    142
    43

    Muratic Acid?
     
  10. fmerkel

    fmerkel Loggerhead Turtle

    # of Dives: 1,000 - 2,499
    Location: Salish Sea (Seattle)
    1,564
    555
    113
    After I realized the problem (no bleed bubbles), I tried cleaning with warm filtered pure water in an ultrasonic. Nope. Tried boiling it in same a bit. Boiled longer. Nope
    Then same with a tad of simple green. Nope.
    Isopropyl alcohol. Nope.
    Got pissed and soaked it in methyl ethyl ketone, by gawd. :rant: Nope.
    Took a Dremel and a small carborundum bit and tried to make it thinner. For a porous metal that thing is sure tough. :mad: Made a tad of progress, and got a few bubbles for my effort, but not even close to spec. :(

    Gave up, got another used one from a generous soul on SB here. Works fine.
     

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