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Servo waterproofing video

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  • Servo waterproofing video

    It's been talked about enough. Here's another video on waterproofing a servo.


  • #2
    I am more excited about his no penetration wireless to control the servo in SALT water!
    thanks Ken!
    If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

    Comment


    • #3
      Have to look further at the specs, a Bluno Beetle has Bluetooth but I think that is for programming it.

      https://www.dfrobot.com/product-1259.html

      This mentions a long range antennae, but not sure what that is for. Further investigation is needed. A much smaller board than an Arduino.

      https://www.dfrobot.com/bluno.html

      Not sure which of the manny Arduino boards support Bluetooth os WIFI control lie the guy in the video did.

      https://store-usa.arduino.cc/collect...hoCjQkQAvD_BwE

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      • #4
        I just found this post (late to the party)- if I were filling a servo with mineral oil, and since the hardest part is getting all the air out, I would do a couple of cycles of vacuum in a bell jar. Also the o-ring installation is good but the sealing area is limited. What if , as long as the case is separated, clamp it in a drill press and machine a chamfer for the o-ring to sit in-BG

        I have found that the only real weak point in waterproofing a servo is the output shaft seal-and that o-ring is key...a dab of epoxy will seal up everything else- I went in a different direction-I use one of Bob's cup seals on the modified output shaft... https://forum.rc-sub.com/forum/gener...lly#post163455 I stopped the test after 5days under 4ft of water out of boredom.
        Last edited by Bob Gato; 10-25-2022, 08:46 AM.

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        • #5
          Originally posted by trout View Post
          I am more excited about his no penetration.....
          Soooooo much humor, soooooo little time.....sigh.
          v/r "Sub" Ed

          Silent Service "Cold War" Veteran (The good years!)
          NEVER underestimate the power of a Sailor who served aboard a submarine.
          USS ULYSSES S GRANT-USS SHARK-USS NAUTILUS-USS KEY WEST-USS BLUEBACK-USS PATRICK HENRY-K432-U25-SSRN SEAVIEW-PROTEUS-NAUTILUS

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          • #6
            Lighten up Francis... The water was cold...

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            • #7
              Originally posted by QuarterMaster View Post

              Soooooo much humor, soooooo little time.....sigh.
              You got that right!
              If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

              Comment


              • #8
                Seems like much concern over getting every bubble out of a servo prior to sealing in the mineral oil.

                Here's my two cents... unless you're planning on running your sub at 100m depth, lighten up. If you end up with a few small bubbles in there, and in a worst case, through operation at depth, end up replacing all of that air with water somehow, the water will sink to the bottom of your servo as oil floats on water. So now your have a few tiny blobs of water sitting in the bottom of your servo, likely a long way from your control board. For external servo mounting, it is advisable to install the servo outputs on the bottom. If you get water in there, it simply sits near the gears and not anywhere near the electronics.

                Again, you can get 98% of the air out of the servo without going to extreme measures. Is getting all of the air out ideal? Yes, of course! Is it the end of the world if you don't? Nuh uh... don't think so.


                Bob

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                • #9
                  Originally posted by RCSubGuy View Post
                  Seems like much concern over getting every bubble out of a servo prior to sealing in the mineral oil.

                  Here's my two cents... unless you're planning on running your sub at 100m depth, lighten up. If you end up with a few small bubbles in there, and in a worst case, through operation at depth, end up replacing all of that air with water somehow, the water will sink to the bottom of your servo as oil floats on water. So now your have a few tiny blobs of water sitting in the bottom of your servo, likely a long way from your control board. For external servo mounting, it is advisable to install the servo outputs on the bottom. If you get water in there, it simply sits near the gears and not anywhere near the electronics.

                  Again, you can get 98% of the air out of the servo without going to extreme measures. Is getting all of the air out ideal? Yes, of course! Is it the end of the world if you don't? Nuh uh... don't think so.


                  Bob
                  The water gets in because of the bubbles. As a rule, a liquid is incompressible, a gas is compressible. Bubbles (hiding in the feed-back pot and motor can) get crushed with depth increasing the differential pressure between the inside and the outside of the servo case, permitting water to find its way into the servo.

                  Getting all the air out IS a big deal.

                  Punch a 1/4" hole in the side of the servo case; dunk the entire servo is a container of cooking oil; subject the entire affair to a hard vacuum (at least 29" of Mercury) wait for all the frothing to stop; break the vacuum and install a flexible diaphragm over the hole. Done. That diaphragm will insure a near zero differential no matter the temperature or depth.

                  Not my first Rodeo!

                  David
                  Former Torpedoman, Launcher Tech and hard-hat Diver
                  Last edited by He Who Shall Not Be Named; 10-28-2022, 09:32 AM.
                  Resident Luddite

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                  • #10
                    I went the other way round, took a normal medium servo and put an o-ring between horn and casing, then coated everything with styrene plating, few layers of grp and done. Works nice since 2014

                    Should it fail i make another and thats it

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