How a proa works / I'm making a 45ft one in Aluminum

Discussion in 'Multihulls' started by SV Pororoca, Jan 8, 2020.

  1. magwas
    Joined: Oct 2009
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    magwas Senior Member

    That machine can do both MIG and TIG. Which one do you do?
    I am an inexperienced welder, and for me TIG is easier when working with aluminum. Because I control the amount of added material by hand, I can more easily maintain the pool, so I am more confident that the weld is indeed strong.
    For checking watertightness, there are weld check sprays.

    (I hope I could contribute something. I know these are basic things.)
     
  2. gonzo
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    gonzo Senior Member

    That is an arrogant and unfounded opinion. Many of us have built hundreds of boats. Get your facts correct before insulting a large group of professionals.
     
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  3. Nixe
    Joined: Dec 2020
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    Nixe New Member

    Hello
    It is easy to get someone down.
    Just write some critical comments from your desk and finish your coffee.
    Sure the weldings on the pictures were not good. Sure any boat could get better with some advice from more experienced boatbuilders. But it is more important that someone gets his dream finished. Perfect or not.
    Have you ever heard of this proa again?
    Alex
     
  4. ALL AT SEA
    Joined: Nov 2013
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    ALL AT SEA Junior Member

    You just answered your own question.
    Poor execution of design and build, combined with a dose of reality from comments from others probably (hopefully) mean the aluminum went to the recyclers before someone got hurt.
     
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  5. gonzo
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    gonzo Senior Member

    I think that for an inexperienced welder the best solution is to tack weld lightly and then hire a welder to finish it.
     
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  6. willy13
    Joined: Jan 2022
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    willy13 Junior Member

    The hardest part with welding aluminum boats is laying a weld without pin holes. With the proper bulk heads and bracing an amature welder can make an aluminum boat that is structural. It just might sink when the bildge pump battery runs out of juice.

    I am curious if pororoca chose to use 5086 aluminum. Its the easiest to weld, and it can actually be fusion welded (no filler), but sometimes isn't the easiest alloy to find at a local metal supply store. I'm not recommending fusion welding in this case, it just shows how nice of an alloy it is for welding.
     
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  7. Ad Hoc
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    Ad Hoc Naval Architect

    The ease of welding, is related to the grade, tempers and the correct filler wire being used.
    The rest is down to how the structure is designed and arranged - whether it allows good access, as well as the skill of the welder.
     
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  8. willy13
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    willy13 Junior Member

    Yes, I agree, and there is a reason you can weld 5086 without filler rod in certain situations.....
     
  9. Ad Hoc
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    Ad Hoc Naval Architect

    No more or less than any other 5000 series alloy....5086 is not unique at all in that sense.
    It is called friction stir welding!
     
  10. rwatson
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    rwatson Senior Member

    You just reminded me of a concept I was considering.

    How would low temperature Aluminium "brazes" go in removing pinholes in a structurally sound welded boat ?

    I suppose the same concept could be considered for steel as well.

    Any downsides ?
     
  11. willy13
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    willy13 Junior Member

    The most popular 5000 series aluminum in my area is 5052. You can not fusion weld (sorry thats the term I use, lol) 5052 without cracking. My only point was that taking the extra effort to find 5086 sheet instead of 5052 sheet is worth it especially for an amature welder.
     
  12. willy13
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    willy13 Junior Member

    My game plan if I was to build an aluminum boat was to MIG everything and then use a TIG machine to fusion weld (sorry for improper term) any pin holes I found. But I am an amature welder, so.... , that learned how to weld 30 years ago after the person I hired to do a weld project F'ed it up.
     
  13. Ad Hoc
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    Ad Hoc Naval Architect

    What are you talking about...you are being very contradictory.

    Thus, please explain and define what YOU mean by fusion welding!
     
  14. willy13
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    willy13 Junior Member

    I was clear on what I consider fusion welding to mean in my first post. I am an amateur welder so my terminology may be off a bit, but I was clear. Its welding without filler rod.

    To reiterate, welding 5052 requires filler rod or it will crack. 5083 and 5086 can be welded without filler rod without cracking. Therefore 5086 can be more forgiving for the amateur welder.
     

  15. Ad Hoc
    Joined: Oct 2008
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    Ad Hoc Naval Architect

    That is called autogenous welding.

    All aluminium, no matter its grade, requires a filler rod.

    Unless you friction stir weld the aluminium, which is a form of autogenous welding.

    Autogenous welding is commonly done on other metals, such as stainless steels etc, but not aluminium, it would have next to zero strength.
     
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