chasing a leak

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  • roedj
    Captain
    • Sep 2008
    • 562

    chasing a leak

    To All.

    I have a WTC from Small World Models that uses O rings for seals. Somewhere in my setup I have a leak that I simply cannot find. And I'm not talking a few drops here, I'm talking about a teaspoon full after maybe 15 minutes. Should be easy to find, right? Well not by me.

    Here's what I've done so far:

    1) Rigged up an entry tube so that I can attach a hose to blow into the WTC and watch for bubbles. Only after I've blown real hard can I force bubbles out through one of the O rings. But I question the validity of this test as it's not a real world situation, I don't think. The pressure inside the WTC should be (is?) less than the surrounding water. Right?

    2) Swapped out the small (ID=1/8") O rings around the servo shafts as well as the Oilite bearing. On this WTC the servo shafts are use rotationally not back and forth. Should I also seal the small O rings into their opening with silicone?

    3) I've put electrical tape around the circumference of the WTC to try and stop water from even reaching the large O rings.

    4) I've replaced the propeller shaft seal with a Merriman designed prop shaft seal.

    5) Assembled the WTC so that only the rear portion is being tested. In doing so I've effectively eliminated over half of the seals as a source of the leak.

    And yet, the flood continues. This is driving me CRAAZZEE! (my family would say it's not a drive but a putt).

    Any ideas?

    Dan
    Born in Detroit - where the weak are killed and eaten.
  • He Who Shall Not Be Named
    Moderator
    • Aug 2008
    • 12256

    #2
    Wait, did I read that right? You blew into the cylinder, got bubbles around an O-ring, and then discounted the validity of the test?

    Is-that-what-you're-telling-me!?.... (With hands firmly around Igor's throat).

    YOU FOUND YOUR LEAK!

    Fix it.

    David,
    Who is John Galt?

    Comment

    • roedj
      Captain
      • Sep 2008
      • 562

      #3
      David,

      Yes ... but... I have to blow really, really hard to cause the bubbles.

      Oh, wait. OK, that's the leak. I'll try sealing it up better.

      Dan

      P.S. It's pronounced EYE-gor.
      Born in Detroit - where the weak are killed and eaten.

      Comment

      • He Who Shall Not Be Named
        Moderator
        • Aug 2008
        • 12256

        #4
        Who is John Galt?

        Comment

        • roedj
          Captain
          • Sep 2008
          • 562

          #5
          I determined that the leak was between the "O" ring and the blue casing and not between the "O" ring and the Lexan cylinder. I guessed that there must have been a very small nick or some other defect that allowed water to escape under the "O" ring. I tried thin CA glue to fill in the nick and it got better but still leaked, I tried more CA but it still leaked so I put some silicone sealant on the spot, smoothed it out with my finger, took it outside in 85F weather and let it bake in the sun for 4 hours.

          Reinstalled the "O" ring, assembled the WTC, put it in my test tank in about a foot of water and let it soak overnight. Next morning checked it - no leaks.

          Picture with silicone sealant applied ...Click image for larger version

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          and a pic with the "O" ring installed...Click image for larger version

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          As always, this is just how I did it - your mileage may vary.

          Dan
          Last edited by Kazzer; 07-08-2011, 08:05 AM. Reason: Enlarged photos
          Born in Detroit - where the weak are killed and eaten.

          Comment

          • Kazzer
            *********
            • Aug 2008
            • 2848

            #6
            What is that WTC? Do you have a photo of the entire thing?
            Stop messing about - just get a Sub-driver!

            Comment

            • Albion
              Captain
              • Dec 2008
              • 651

              #7
              small world models

              The nice thing is the rotary outputs for the servos

              The bad thing, is the rotary outputs for the servos - i found mine started leaking if the servos werent just right
              Next time someone points out it takes 42 muscles to frown, point out it will only take 4 muscles to b1tch slap them if they tell you how mnay muscles you need to smile:pop

              Comment

              • He Who Shall Not Be Named
                Moderator
                • Aug 2008
                • 12256

                #8
                So, do tell: was this where you saw the bubbles?

                David
                Who is John Galt?

                Comment

                • roedj
                  Captain
                  • Sep 2008
                  • 562

                  #9
                  Once more unto the breach....

                  Mike, I hope this is what you were asking for.

                  Various pix of Small World Models WTC as designed for their 1:96 Blueback.

                  servo and motor compartment...Click image for larger version

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ID:	63007Click image for larger version

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                  servos with adaptor caps...Click image for larger version

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                  servos mounted in motor compartment...Click image for larger version

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                  motor bulkhead ...Click image for larger version

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ID:	63011... mounted on motor/servo compartment...Click image for larger version

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                  add the Lexan 'engine room' cylinder...Click image for larger version

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                  ballast compartment - wet side...Click image for larger version

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ID:	63014... and dry side...Click image for larger version

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                  attach the ballast compartment to the 'engine room' ...Click image for larger version

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                  battery and radio compartment...Click image for larger version

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ID:	63017... attached to ballast compartment...Click image for larger version

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                  radio room - I like to separate my radios from any motors or ESC's as far as possible...Click image for larger version

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                  the completed WTC...Click image for larger version

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ID:	63020... mounted in the bottom of the Blueback...Click image for larger version

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                  Blueback in Carmel Measure #3

                  Dan
                  Attached Files
                  Born in Detroit - where the weak are killed and eaten.

                  Comment

                  • tsenecal
                    Lieutenant
                    • Dec 2009
                    • 63

                    #10
                    having owned one of these for several years, i have three questions:

                    1a) where is your battery?
                    1b) what is your battery?
                    2) why do you have a pump?
                    Last edited by tsenecal; 07-08-2011, 03:21 PM.

                    Comment

                    • He Who Shall Not Be Named
                      Moderator
                      • Aug 2008
                      • 12256

                      #11
                      Dan,

                      Thanks for the photo essay on Dave Manley's WTC. Well done shots and most instructive.

                      Dave, I assume, is out of the game at present. But, for over ten years he produced both fine hull kits and innovative and reliable WTC's like the one pictured above.

                      Dan, nice installation of that *** in the after dry space, by the way.

                      Gotta ask: Where did that color scheme come from?

                      David
                      Who is John Galt?

                      Comment

                      • roedj
                        Captain
                        • Sep 2008
                        • 562

                        #12
                        Originally posted by tsenecal
                        having owned one of these for several years, i have three questions:

                        1a) where is your battery?
                        1b) what is your battery?
                        2) why do you have a pump?
                        1) Click image for larger version

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                        1b) Click image for larger version

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ID:	63024... although I have to adjust weights for trim because batteries are not same weight

                        2) pump is Caswell SNORT...Click image for larger version

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                        I rarely use Propel anymore especially in 'safe' areas. I set the trim for slightly positive buoyancy, drive the sub to the surface and turn on the SNORT pump. Simple and very effective.


                        David,

                        Colors came from my observation of bottom of Carmel pool and guessing what would blend in best. There's a few of us 'crazies' who take delight in making a sub vanish in the Carmel pool. Keeps everyone else on their toes - LOL.

                        Dan
                        Born in Detroit - where the weak are killed and eaten.

                        Comment

                        • roedj
                          Captain
                          • Sep 2008
                          • 562

                          #13
                          Originally posted by Merriman
                          So, do tell: was this where you saw the bubbles?

                          David
                          Yes - glad I found it on my own - cough, cough...

                          Dan
                          Born in Detroit - where the weak are killed and eaten.

                          Comment

                          • He Who Shall Not Be Named
                            Moderator
                            • Aug 2008
                            • 12256

                            #14
                            Originally posted by roedj
                            Yes - glad I found it on my own - cough, cough...

                            Dan
                            Ha!...........
                            Who is John Galt?

                            Comment

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