Aluminum keel & chine Extrusions

Discussion in 'Metal Boat Building' started by sboyle, Aug 11, 2013.

  1. sboyle
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    sboyle New Member

    Has anyone located an Aluminum extruder in North America that extrude's keel and chine extrusions. I have located them in AU but that not cost effective. There were some listed in the few books that cover Aluminum boat building but they have moved or gone out of business
     
  2. gonzo
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    gonzo Senior Member

    Do you have a drawing of the extrusion section?
     
  3. Ad Hoc
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    Ad Hoc Naval Architect

    It is not recommended to use 6000 series extrusions below the waterline.
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    So what extrusions are suitable below the waterline ?
     
  5. Ad Hoc
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    Ad Hoc Naval Architect

    From the 5000 series, "marine" grade of course.
    But these are generally more expensive and limited in their size and shape owing to this series being non-heat treatable.
     
  6. sboyle
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    sboyle New Member

    I have all my plate and weld wire acquired and the companies that were making the extrusions are out of business. Hoping to come across a company that has dies for these extrusions. Understand the required usage of 5000 series materials. I have located all the other type of extrusion that I need.
     

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  7. richard gray
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    richard gray Junior Member

    exstrutions

    they could be made up by bending and welding 3 pieces in this shape. fillet weld or plug weld
     
  8. Ad Hoc
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    Ad Hoc Naval Architect

    sboyle

    How big is your boat?

    I also notice you're in Redding. Lovely part of California.
    Is your boat thus for fresh water lakes, rivers, not sea/coast?
     
  9. sboyle
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    sboyle New Member

    The boats will be a couple of Alum dinghys in the 8' range and a small 18'cruising Sloop possibly.
    The keel & chine extrusion are so the the bottoms of the dinghys will wear better on the Baja beaches. Fiberglass gets eaten up on the Baja beachs.
    Redding is just where I work next job is Reno.
    Have a Bristol Corsair 24' undergoing a complete rebuild.
     
  10. Ad Hoc
    Joined: Oct 2008
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    Ad Hoc Naval Architect

    For the keelson, why not just use a thick FB...say 40mm or 30 by 20mm thick and butt the hull bottom into the thick FB, which is almost a solid block. If 20mm is too much say 15mm or 10mm, select one that suits you best. It will act as a rubbing strake and some local strength too. This can be made/cut from 5083 plate too. Perfect!

    Just a thought.
     
  11. sboyle
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    sboyle New Member

    There will be some wear strips on the bottom but the extrusion will be to join the two bottom plates together.
     
  12. tazmann
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    tazmann Senior Member

    the extrusions are not really necessary, I have done a couple 8 footers and a 10' without them using .100" 5052 material . Keel and chine seams setup inside edge to edge.
    Tom
     

  13. peterroderick00
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    peterroderick00 Junior Member

    amongst other things ,I have enough experience as a machinist have worked at a tool making facility, my shop is near atlantic city nj & I have a few connections with tool & die shops,the extrusion dies are relatively simple compared to say a coca cola bottle that a tool shop usually makes molds for ...it may be a good idea to have a die made to an extruders spec with your extrusion shape in it...& as simple as they are & as many people on this forum as there is im sure someone could use a cad program to design your shape in about 10 mins & a tool maker could make a die for you that you could approach an extrusion shop with..my experience is all non computer machining & I could even make one manually in short time, I`ve heard an extrusion shop will sometimes trade to varying levels with you for the use of your extrusion shape after your done with it...just an idea ,& for as much help as I`ve got on this forum I wouldn't at all mind paying the good treatment forward...if I can help let me know, but do understand I have no experience extruding ,just machining & im only repeating what ive heard "around the campfire" about them trading...either way it can be done reasonably im sure as the dies are usuall just a round blank of some thickness with the required shape machined in the blank to tight tolerance of course but that's not a dilemma for any competent machinist..i hope the info helps
     
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