Announcement

Collapse

Forum rules and expectations

Hello, and welcome to the forums at the Nautilus Drydocks, formerly Sub-driver.com!

We welcome anyone with a passion for submarines and a desire to learn and share knowledge about this fascinating hobby. Use of these forums indicates your intention to abide by our code of conduct:


1. No spam. All automated messages, advertisements, and links to competitor websites will be deleted immediately.

2. Please post in relevant sub-forums only. Messages posted in the wrong topic area will be removed and placed in the correct sub-forum by moderators.

3. Respect other users. No flaming or abusing fellow forum members. Users who continue to post inflammatory, abusive comments will be deleted from the forum after or without a warning.

4. No threats or harassment of other users will be tolerated. Any instance of threatening or harassing behavior is grounds for deletion from the forums.

5. No profanity or pornography is allowed. Posts containing adult material will be deleted.

6. No re-posting of copyrighted materials or other illegal content is allowed. Any posts containing illegal content or copyrighted materials will be deleted.
See more
See less

Beginner question! Sealant!

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Beginner question! Sealant!

    Hi rc-sub.com!!

    QUESTION: How to best seal the deck, and prop shafts?

    BACKSTORY:
    Want to get into RC Subs, specifically plastic model conversions. Created a progression:

    1. Fix an old broken RC ship that was taken completely apart.

    2. Convert a cheap plastic model ship kit to RC.

    3. Convert a cheap plastic model sub kit to dynamic dive.

    4 Convert a cheap plastic submarine kit to static diver.

    5. FINAL: Convert a old Revell 1/72 Gato kit to static diver RC.

    In light of that, a challenge on step one I am having is sealing the shafts to the hull (preventing water entry between hull and the metal shafts), and water that enters between the deck and the plastic sides. The ship is a 30” destroyer with a deck that I pulled off to work on the inside (very similar to a plastic model kit).

    Any help is appreciated! Newbie here.

  • #2
    Sleeve the propeller shaft(s) in a 'stern tube' that is glued to the hull. The fit between propeller shaft and stern tube is a close, non-interference fit. Lubricate with thick grease.

    I like your approach: one-step-at-a-time. Slither, crawl, walk, jog, run, and finally sprint.

    David
    Resident Luddite

    Comment


    • #3
      As David said, You need a stern or stuffing tube. Click image for larger version  Name:	Screenshot_20220728-074930_Shopee.jpg Views:	0 Size:	58.2 KB ID:	163209Click image for larger version  Name:	Screenshot_20220728-074956_Shopee.jpg Views:	0 Size:	54.5 KB ID:	163210
      Last edited by redboat219; 07-27-2022, 08:29 PM.
      Make it simple, make strong, make it work!

      Comment


      • #4
        Forgive me, I messed up my terminology. The shafts are in working stuffing tubes, the problem is preventing water from entering from where the stuffing tube passes through the hull, along with the connection between the top of the hull and the deck.

        Comment


        • #5
          Stuffing tubes are usually epoxied in place. You can attach the deck to the hull using rtv silicone but most glue it place then cut access holes on top of the deck under the superstructures.
          Click image for larger version

Name:	004.jpg
Views:	140
Size:	58.6 KB
ID:	163218Click image for larger version

Name:	003.jpg
Views:	121
Size:	56.1 KB
ID:	163219
          Last edited by redboat219; 07-27-2022, 11:49 PM.
          Make it simple, make strong, make it work!

          Comment


          • #6
            Is there a recommended epoxy, or recommended method of application? Never epoxied anything before. For the stuffing boxes, I tried marine silicone with leaking during testing.

            Regarding RTV Silicone, is there a recommended one? What is the difference between that and marine silicone, and how to best apply?

            How does one seal that cut out access panel? Especially if it’s meant to be opened and closed.

            Lots of questions I know. Appreciate all the help I can get to learn my way into this.
            Last edited by GatoGaterDom; 07-28-2022, 10:39 AM.

            Comment


            • #7
              Originally posted by GatoGaterDom View Post
              Is there a recommended epoxy, or recommended method of application? Never epoxied anything before. For the stuffing boxes, I tried marine silicone with leaking during testing.

              Regarding RTV Silicone, is there a recommended one? What is the difference between that and marine silicone, and how to best apply?

              How does one seal that cut out access panel? Especially if it’s meant to be opened and closed.

              Lots of questions I know. Appreciate all the help I can get to learn my way into this.
              Any 12–24 hour cure epoxy. Thicken with talc so it does not run.

              Any 'gasket making' RTV (room temperature vulcanizing) silicon 'adhesive'. Fingers.

              1/4" tall hatch combings, or if flush-mounted a gasket made of RTV -- lay down a bead on the deck flange, coat the lid with Vaseline, then compress onto the opening and wait for the RTV to cure. Instant in-place hatch gasket.








              Resident Luddite

              Comment


              • #8
                Ok this is making sense now.

                Tomorrow morning I will hit the auto parts store for epoxy and RTV. I did some research on RTV gaskets using sources geared towards car mechanics and that helped develop my understanding of how to properly make a seal.

                That being said, why would one apply vaseline to the top of the RTV?

                From what I understand, I am to cut a portion of the deck out, create a "lip" that sticks out into that gap, apply the RTV onto that lip so as to create a hatch gasket when I push the cut out portion of deck back onto that lip. Where does the vaseline come into play? And does the RTV need to be reapplied every time I open that access panel?

                Dom

                Comment


                • #9
                  So that you don't inadvertantly "glue" the deck hatch on to the flange. The vaseline prevent the RTV from sticking to the underside of the hatch.

                  Click image for larger version  Name:	Screenshot_20220729-123659_Samsung Notes.jpg Views:	0 Size:	48.6 KB ID:	163244
                  Last edited by redboat219; 07-29-2022, 12:38 AM.
                  Make it simple, make strong, make it work!

                  Comment


                  • #10
                    UPDATE:

                    FOCUS: How to prevent water entry through inside stern tube, without replacing tube?


                    MORE INFO:

                    Techniques to seal the deck, a hole, and the connection between the stern tubes and the hull have all passed testing. The vessel has passed a 20 minute float test with zero water entry. Thanks.

                    The vessel then failed a 10 minute engine full power test (being held in bathtub, not actually moving forward). Water entry was observed coming out the stern tube, particularly the port side tube at high engine speed.

                    What could be causing this? The tubes have worked fine in the past.

                    Is there a way to fix it without disturbing the seal between hull and stern tube?


                    Last edited by GatoGaterDom; 08-10-2022, 05:31 PM.

                    Comment


                    • #11


                      If it's coming between the tube and hull vibration from motor testing must have shaken things loose. Just re-apply some more epoxy and let it cure fully before doing any more testing.
                      Last edited by redboat219; 08-11-2022, 01:58 AM.
                      Make it simple, make strong, make it work!

                      Comment


                      • #12
                        Water is observed exiting the stern tube into the hull, particularly while at high RPM. Water is entering through the inside of the stern tube. Water is NOT entering between the tube and the hull, that seal (JB Weld) is perfect. Which is why I would like to repair the stern tube without ruining that seal if possible.

                        Comment


                        • #13
                          Have you packed the stern tube with a waterproof grease? I use the blue speed demon grease or the green tourmaline grease that is used on the 1:1 real things.

                          Pull your shaft and coat it in grease, and then pack some into the tube. Push the shaft back in, the excess will push out the other end. That Should take care of the leak.
                          Last edited by SubICman; 08-11-2022, 06:17 PM.

                          Comment


                          • #14
                            Questions.
                            - did you apply grease inside your stuffing tube?
                            -does you stuffing tube have bushings at the ends that acts as bearings and standoff between the shaft and tube to contain the grease?
                            -Are you using a solid shaft or a coiled wire flexible shaft? A coiled wire shaft could act like an Archimedes screw that draws in water when the motor runs in a particular direction.
                            Make it simple, make strong, make it work!

                            Comment


                            • #15
                              Click image for larger version

Name:	images.jpeg
Views:	50
Size:	56.0 KB
ID:	163623
                              Make it simple, make strong, make it work!

                              Comment

                              Working...
                              X