WTC end cap material

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  • Michael440
    Lieutenant, Junior Grade
    • Mar 2021
    • 37

    WTC end cap material

    Hi, more then likely asked hundreds of times before. But what is the best material that does not cost the earth to use for WTC end caps. I tried 3D printing them, but not happy with results. So what to use. The WTC is 110mm across so it’s a big lump. I am also in the land of expense, ie the uk. I do have a lathe so can turn material down to size.
  • Rick Teskey
    Lieutenant Commander
    • Jan 2009
    • 233

    #2
    Turning on a lathe pvc solid rod

    Comment

    • redboat219
      Admiral
      • Dec 2008
      • 2735

      #3
      O-rings:


      Endcap Fabrication:

      Make it simple, make strong, make it work!

      Comment

      • Subculture
        Admiral
        • Feb 2009
        • 2119

        #4
        Don't take any notice of those vids, the bloke on there has no idea!

        Most thermoplastics are suitable, e.g. pvc, pmma (acrylic), polycarbonate, polypropylene, polyethylene, you can also use aluminium and composites like GRP or Tufnol. I find it's cheap enough- I'm in the UK too. Lot of cheap-usually free- offcuts at signmakers, but failing that you can buy new from ebay and direct plastics.You don't need loads of plastic, and the cost is small when compared with ready machined units. https://www.directplastics.co.uk/

        I would say you should be able to get very acceptable results with 3d printing, so if you're unhappy, maybe you need to work on that. A major advantage with printing is that you can easily make endcaps domed/hemispherical, which makes them much stronger under water pressure and thus you can make them thinner.

        If you still want to use sheet and you haven't got a lathe or someone around to machine them for you, then you can use hand tools to bench fit them. Much easier to use axial seal compression if making the endcaps by hand as you only need to cut out a pair of discs by hand and bond them together, and the tolerances are more forgiving than radial compression. You will need draw bars to compress the seal though, which take up room and will need sealing if you run them internally.
        Last edited by Subculture; 03-22-2021, 12:37 PM.

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        • type7
          Lieutenant Commander
          • Apr 2009
          • 152

          #5
          Use a circle saw to cut and stack sheets of acrylic or polycarbonate sheets. Very easy to sand or turn to o-ring dia. About as simple and dirt cheap as you can get.

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          • Subculture
            Admiral
            • Feb 2009
            • 2119

            #6
            That'll be a big ol' hole saw for 110mm discs!

            A trepanning tool would be more appropriate if you have one. Lots of ways to skin this cat.

            Comment

            • RCSubGuy
              Welcome to my underwater realm!
              • Aug 2009
              • 1768

              #7
              Ditto on the printing comment. There is no reason that you can't print end caps. What is the issue you're having? You're printing solid, I assume?

              Bob

              Comment

              • Michael440
                Lieutenant, Junior Grade
                • Mar 2021
                • 37

                #8
                Thanks chaps, I can cnc cut the material so no need for band saws etc. With the 3D print. Even with 100% infill, I just wanted better. I will take a look at sign writers off cuts. Thanks again.

                Comment

                • Subculture
                  Admiral
                  • Feb 2009
                  • 2119

                  #9
                  You want 7-8mm minimum thickness for the endcaps if using unreinforced thermoplastics.

                  Comment

                  • Michael440
                    Lieutenant, Junior Grade
                    • Mar 2021
                    • 37

                    #10
                    Hi chaps, I just remembered I have a large lump of aluminium which would be good for end caps, so will work with this. Thanks for input. The problem I had with 3D printing, was that even with 100% infill, the part came out looking good, size ok, but it was let down by poor areas around the smaller holes for props etc. I just did not like it. However 3D printing motor positions etc came out nice.

                    Comment

                    • Subculture
                      Admiral
                      • Feb 2009
                      • 2119

                      #11
                      I don't find the need to use 100% infill to make parts look nice.

                      I find a lot depends on how the machine is set-up, the filament you are using and your slicer settings.

                      I use PLA, with Cura slicer, and I set it up to iron the top surfaces, that gives a very good finish on parts. I use a minimum of three walls for structural parts, and the most i tend to use for infill is 25%, and i like using the gyroid pattern.

                      For very fine finish parts need to be post processed however, but that isn't a big deal, I just treat them like castings.

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