Plastic Drums waterproofing

Discussion in 'Boat Design' started by Pedro, Aug 15, 2021.

  1. Pedro
    Joined: Jan 2020
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    Location: London

    Pedro Junior Member

    Hi
    I'm in the process of building a 3x2M (10x6ft) boat on 6 220L containers.

    These containers have two holes, one has a threaded cap which should be completely watertight if tightened well using PTFE tape, but the other seems to have like a peel off type of cover.
    I'm wondering on the best way to have this second entrance completely watertight before submersion. I sent two emails to the seller, but they don't seem like they like replying...
    Actually, they may have sold me the wrong one, as the photo on their website shows the drums with two tight head (threaded) covers, and I got them with one tight threaded and one peel off type one.
    What I got is actually more similar to these ones from a different seller, link in case the photo I'm tying to upload won't work.
    Is anyone familiar with this type of cover? Any advice would be welcome.

    Thanks
     
  2. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    A picture would help.

    I had a hole in a plastic barrel. Here is what I did. I roughed the area with 40 grit sandpaper and cleaned it well.

    Epoxied a 6"x6" patch over the hole. One piece of 600/225 glass or 1708 (same thing). Glassed with csm down.

    For you, paint them. I did not. The barrel has held water four years.
     
  3. fallguy
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    fallguy Senior Member

    I see the barrel tops are not even. To glass patch them, you will need to add some filler to the top edge. Be careful, they look a bit deep and too much filler can burn or catch fire. Limit fills to 10mm and wait one hour between fills to flatten the area for glass patch.

    I think those are vents.
     
  4. Rumars
    Joined: Mar 2013
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    Rumars Senior Member

    That type is tight with the appropiate metal ring and gasket, but the ring will rust (never seen a 316 ring, although maybe they exist). You can have them weld shut by someone doing HDPE welding.
     
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  5. fallguy
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    fallguy Senior Member

    Much cleaner to hdpe weld!
     
  6. bajansailor
    Joined: Oct 2007
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    bajansailor Marine Surveyor

    What are you planning on using this little barge for Pedro?
    Re the two holes, you could arrange the barrels in the raft such that the watertight one is on the bottom, and the nonwatertight (currently) is on the top?
    The total buoyancy of the six barrels is 1,320 litres, but you should not go beyond half immersion, so lets say 650 litres, or 650 kg in fresh water.
    What is your anticipated payload?
    And how are the barrels attached to the barge -can you post a photo or two please?
     
  7. ondarvr
    Joined: Dec 2005
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    ondarvr Senior Member

    Without a pic or link ( I don't see any) I would say you can thread the hole and screw in a plug.

    Since you don't want drums immersed more than 50% at maximum load, and that's with a safety factor on the load and immersion, the holes would rarely, if ever be underwater for more than allowed for by some wave action.

    My drums had the bungs set parallel to the water's surface and had no water ingress after over 5 years.

    There was never a time when the bungs were underwater.
     
  8. BlueBell
    Joined: May 2017
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    BlueBell "Whatever..."

    I too am unable to post pictures Pedro.
    You're not alone.
    What orientation will the barrels be in?
     
  9. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    Yes, you got the wrong type. The cheapest solution is to swap them for ones with only one bung, or ones with both bungs threaded. We used to be able to get these delivered to our door for $8 a pop, but that was in south Florida where they were used by the millions for orange juice concentrate. Also check with any commercial establishments that uses a lot of bleach or degreasers. Many commercial janitorial suppliers supply chemicals in these drums for pools, laundrys, and shops.
     
  10. Pedro
    Joined: Jan 2020
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    Pedro Junior Member

    Thanks fall guy. I don't know about glassing and would not like this to be my first try :( but if that is the best option I will have a go. I have four extra barrels, so I can practise on them.
     
  11. Pedro
    Joined: Jan 2020
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    Pedro Junior Member

    Well, probably not, and I will be counting on that. Not many waves on the Thames or London canal system in London, but eventually I would like to cross the Channel and take it to the Danube (dreams...) and for that the said holes may get a lot of splashing onto them.
    I may have the threaded one at the lowest point and the red one across just in case.
     
  12. Pedro
    Joined: Jan 2020
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    Pedro Junior Member

    That's an interesting reply, as it also provides information I did should have researched but didn't :) Thanks a lot for that.
    My payload I don't know exactly, but expect it to be not over 400 kg, and that's if I get a fat lady to visit ;) But seriously, I think the platform and cover (like a small shed) 70kg more, then myself and engine and other stuff 70 kg more.
    Way below your calculation. In addition, I am reserving two gaps where I could fit two more barrels in the future if needed.
    The barrels are attached to the underneath of the platform with metal straps.

    Sorry can't post photos here. I think it's only after being a member for some time. Or I didn't do it properly when I tried.
     
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  13. Pedro
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    Pedro Junior Member

    Parallel to the platform, like a very poor man's catamaran type of thing.
     
  14. Boat Design Net Moderator
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    Boat Design Net Moderator Moderator

    To post a photo, click on "Upload a File" under the reply area and you can select a jpg to include with your post.
     

  15. Pedro
    Joined: Jan 2020
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    Pedro Junior Member

    Tragically, I am not anywhere near Florida. I'm in Britain, where not many people use these, and buying second hand is not cost-effective. I bought these new for the equivalent of just over $40 each.
     
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