shaping aluminium with explosives

Discussion in 'Boatbuilding' started by sand groper, Jul 19, 2010.

  1. sand groper
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    sand groper Junior Member

    Dear all, forgive me if this has been posted previously.
    I recall an Australian boating magazine story from the 70's / 80's about an attempt to create alloy hulls using a sheet of aluminium that was forced into a female mould by explosive charges.
    Imagine a concrete swimming pool in the shape of the desired hull with a sheet of aluminium draped over it. An air-burst explosion over the mould then forces the sheet into the required shape - I don't recall whether the mould had vents or the like, but there was a photo of the mould and maybe it was attempted. Can't imagine it working though.
    regards, Rex
  2. jonr
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    jonr Senior Member

    It's similar to hydroforming. I heard that it worked, but I can imagine that getting the details all correct can be tricky.
  3. sabahcat
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    sabahcat Senior Member

  4. sand groper
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    sand groper Junior Member

    So it did work. Excellent - thank you.
    And has the process been used again ?
  5. lewisboats
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    lewisboats Obsessed Member

    Cool!!! BOOM...A boat!
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  6. Herman
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    Herman Senior Member

    I have seen this construction method, however not on boats, but on artwork, and in the production of Tri-Clad.

    I guess boats are a bit big to perform this kind of actions. Unless you have an unlimited supply of explosives.

    I once read an interview on a guy doing all kind of crazy things with explosives, and he was asked how he got the explosives. Well, he said, I work in demolition, and the fun is to demolish as much as possible, with as little dynamite as possible, so on every project a couple of sticks of dynamite fall free. Guess where they end up...

    Perhaps apply for a job at "Controlled Demolition"?
  7. daiquiri
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    daiquiri Engineering and Design

    I guess some National Security Agencies might want to know that, too. :rolleyes:
  8. CDK
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    CDK retired engineer

    There's a TV show called Mythbusters on Discovery channel. They are the right guys for such an experiment!
  9. keith66
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    keith66 Senior Member

    I remember reading the article in Yachting Monthly, the boat was a Gelignite 32?
    the mould was in the ground, concrete lined with inch or so square steel bars with gaps between. The alloy sheets that made up the hull were dropped into the mould & mig welded in sections. the unformed rough hull was then filled with water & small explosive charge only a few ounces placed in the middle. on firing the hydraulic shock formed the hull to the mould in sparrows fart time.
    The other interesting thing was they then fitted the stringers with 3m double sided tape used to build helicopter rotor blades.
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  10. Herman
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    Herman Senior Member

  11. Robbo
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    Robbo Junior Member

    I saw the same thing, but Im sure it was on a show on Oz TV called Beyond 2000.
  12. Remmik
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    Remmik New Member

    Here is a YouTube video of the video segment for this boat builder. It’s from a bad video tape and you can tell it’s fresh into the 90’s with the 80’s style the reporter sports :D
    I found this looking at hydro explosive forming of cylinder tanks made from single angled rolled steel sheets into multi directional angled pieces to make a sphere.
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  13. Barry
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    Barry Senior Member

    Somewhere in my aluminum boat building books there was a reference to a person using this method to form complex curves in aluminum boats but if I remember correctly the trial and error process was extremely expensive.
    But within the same book was a reference for a material called Triclad and attached is a short explanation of joining aluminum to steel using explosives to enable a ship to have a steel hull and have it welded to an aluminum superstructure.
    Steel Hull & Aluminum Superstructure Yacht Construction - Bering Yachts
  14. Dejay
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    Dejay Senior Newbie

    At first this sounds stupid but after seeing the video it makes sense haha. You deliver the force to shape the metal without requiring some super high pressure system or use wheeling to create compound curvature.

  15. upchurchmr
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    upchurchmr Senior Member

    My aerospace company did work like this before I got there. Think 1970's.
    They were trying to make thicker aluminum pieces (and other metals) in order to reduce the machining / forming cost.
    They also tried to form the aluminum while coating an area with steel or ti.
    It all worked, but it was not perfectly controllable. They ended up having to make the preliminary parts too big, since they could not get "close" to the desired size.
    So they had to heavily machine the formed part. Additionally, it was a real problem setting up the formed part on the machine table to get an actual part without flaws after machining.
    Very costly, difficult, and time consuming setup.
    But there were some really interesting interfaces between the steel/ ti and aluminum - it looked like a series of ocean waves caused by the intermixed materials.
    Then there is a question about the long term corrosion potential between two incompatibale materials.

    Would have been fun to experiment.
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