Ss inserts in chainplates

Discussion in 'Metal Boat Building' started by John Dickie, Jun 14, 2021.

  1. John Dickie
    Joined: Apr 2019
    Posts: 25
    Likes: 2, Points: 3
    Location: South Africa

    John Dickie Junior Member

    Is welding in 316 drilled inserts into mild steel chain plates a good idea? Prevent rust stains, hopefully. I came across this idea donkey's years ago, but forgot to do it timeously:)
     
  2. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    I think that I can see some of the chainplates mentioned standing proud of your timber deck in this photo -

    BDF - John Dickie's 32' steel hull timber deck.jpg

    This photo is in John's other thread here -
    solid Iroko cabin trunk https://www.boatdesign.net/threads/solid-iroko-cabin-trunk.63859/page-2

    Re welding inserts into these chainplates - I will just say that that weld area looks to be uncomfortably close to the timber deck.
    Are you proposing to chop the tops off the chainplates, then butt weld on new S/S plates, or to drill out a large hole in each plate, and then weld in a round section of S/S - or another method I have not thought about?
    Would it be feasible to weld a thinner strip of S/S on each side of the chainplate, to act as a chafe guard?
     
  3. John Dickie
    Joined: Apr 2019
    Posts: 25
    Likes: 2, Points: 3
    Location: South Africa

    John Dickie Junior Member

    20210615_155841.jpg 20210615_153056.jpg
    Thinking of Tig welding 12mm ssrod into the chainplates. Been some progress
     
  4. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    She is looking very impressive John, especially so now that you have the cabin trunk and bulwarks on.

    Re welding the 12 mm rod into the chainplates- I presume that you would drill out the existing holes to say 13 mm diameter, weld in the sections of rod, and then drill them to suit the diameter of the clevis pins in your rigging?
    Or would you drill them first in a press before welding them in?
     
  5. John Dickie
    Joined: Apr 2019
    Posts: 25
    Likes: 2, Points: 3
    Location: South Africa

    John Dickie Junior Member

    Pre drilled and a tight fit-minimal tig to reduce heat input. It's got 10 coats of paint, and some of the areas will be very difficult to fix. I guess I'll do the easy ones first, and take it from there. Still not sure it's the best course of action. Will 304 work in this location? Crevise corrosion should not be an issue, or am I missing something?
     
  6. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    I am thinking that it would still have to be 'continuous' welded on each side, so that it doesn't rust underneath if it is simply 'tacked' - and continuous probably does not go well with minimal?

    In view of how you have 10 coats of paint already on these chainplates - do you have this much paint already in way of the holes required for the inserts?
    If you do, would it be feasible to put in composite shims instead of the S/S inserts (maybe glue them in 5200 or similar).
    And then the clevis pins could bear against the shims (?)
     

  7. John Dickie
    Joined: Apr 2019
    Posts: 25
    Likes: 2, Points: 3
    Location: South Africa

    John Dickie Junior Member

    By minimal tig welding I meant a very shallow, low heat input weld, but continuous. The holes in the chainplates are only 2mm oversized for the pins. This task is still a few months away-next up is glassing the coachroof. Can't say I'm looking forward to it:)
     
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