Looking for Spline Weights

Discussion in 'Boat Design' started by swan1, May 1, 2014.

  1. swan1
    Joined: Apr 2014
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    swan1 Junior Member

    Please if someone has some drafting whales/ducks/weights for sale, let me know. I'm currently based in Sarasota, Florida USA. Cheers.
     
  2. messabout
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    messabout Senior Member

    You can make your own if you do not find them here or elsewhere. Get some scrap lead from the salvage yard or from a tire dealer. Lead weighs 0.41 pounds per cubic inch. A five pound duck would need about 12 in^3. Home built ones are not as pretty as professionally made ones but they work just as well. A little bit of paint and a sheet cork bottom makes them presentable.
     
  3. swan1
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    swan1 Junior Member

    Will do tnx.
     
  4. NavalSArtichoke
    Joined: Oct 2013
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    NavalSArtichoke Senior Member

    Here are a couple of off-beat batten weight sources:

    http://digiitalarchfab.com/portal/wp-content/uploads/2011/03/LOFTING-DUCKS-Spline-Weights.pdf

    Ducks in bronze instead of lead:

    http://www.edsonmarine.com/marinestore/index.php?main_page=index&cPath=108

    It looks like the objets d'art are cheaper than the bronze variety.

    You can find articles online about making your own, but it looks like a lotta work. Always be careful handling molten metal and don't inhale any fumes.
     
  5. swan1
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    swan1 Junior Member

    Thanks for your help and advice. Reasonable price on link I guess, anyway will try to cast one soon.
     
  6. messabout
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    messabout Senior Member

    The links show some nice ducks but they are rather pricey.

    About messing with lead: You can melt the lead on a simple hot plate, Lead melts a relatively low temperature. Just throw some scrap into a sauce pan that you do not mind sacrificing and melt.

    Here are warnings. Be damned sure there is no water or moisture of any kind in the mold that you are going to use. You can make a perfectly serviceable mold cavity from plaster of paris. The right idea is to make the mold and forget it for a week or so until all vestiges of moisture are gone. If you use a plaster mold, build a box or frame for it so that it cannot come apart when you pour hot lead into it.

    When making the mold allow for some molding draft. That is to say, the top surface will be a bit wider than any surface below it. I think that is an obvious requirement. If it suits your purpose you can make the ducks in two parts, as in a top and bottom section. That way you can easily put in the L shaped wire part that contacts the spline. Epoxy the two parts together. I have epoxied lead parts that were not subject to impact or heavy load, with no subsequent problem. Doing it that way gives you some leeway to design as you please. It really does not need to look like a whale unless you want it that way.

    When the lead is melted all kinds of crap will float to the top, including the steel clips if you have used wheel weights. Skim off the dross and floating objects and dispose of it discretely and carefully. When you pour the lead do it slowly and very very carefully so that it can not splash. This is a dangerous operation and the very greatest care and attention to safety is essential. Look before you leap.
     
  7. DCockey
    Joined: Oct 2009
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    DCockey Senior Member

    I cast a set of "ducks" in a plaster of paris mold when I was fifteen. The lead was purchased at a hardware store at a very reasonable price. At that time molten lead was used to seal joints in cast iron drain pipe. The lead was melted in a plumbers lead pot on one of the burners of my mother's stove. I pre-heated the mold in the oven, and cast the lead using a plumbers ladle on the front porch.

    The mold was cast around a wood pattern with some wire embedded. The idea of the wire was to reinforce the mold and it held the mold together when it cracked during the last lead casting. If I did it again I'd make the mold in a wood box.

    The hooks were bent finish nails with a filed chisel end, epoxied into drilled holes. Drilling the holes was the only significant problem. On the first attempt to drill a hole the twist drill dug in and snapped. A family friend who was a very talented machinist bailed me out. He reground a drill bit with a very flat angle so that it scrapped rather than cut the lead.
     
  8. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    Davids experience with drilling lead is typical. Lead 'bites'

    try to cast the wires when you pour them.

    Messes advice to use aluminium pots ( especially old alu teapots with a spout ), works great.

    You will be able to melt the lead over a small gas burner.

    If you go around to to tyre sellers, they seem to have lots of lead weights either cheap or free.

    PS - putting lead tyre weights or fishing sinkers embedded in epoxy in a mould is the easier way to get smooth, heavy ducks with no fumes and burns
     
    Last edited: May 4, 2014
  9. swan1
    Joined: Apr 2014
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    swan1 Junior Member

    All most valuable posts here tnx. What minimum weight is recommended per unit in relation to spline material? I've seen from 3 to 5 lbs metal each, even a wooden made with lead filling.
     
  10. SamSam
    Joined: Feb 2005
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    SamSam Senior Member

    I don't even need any but it looks kind of fun to do.

    http://www.duckworksmagazine.com/06/howto/splineweights/index.htm

    While your at it, a bit of decorative flourishes would be worth the effort.

    [​IMG]

    http://www.boatdesign.net/forums/boat-design/need-spline-weights-420.html

    Somewhere I was reading that while lead melts at 650 degrees or so, it pours into molds better at 900 degrees or thereabouts. I don't know at what temperature an aluminum pot might melt.

    Again, the fumes are extremely toxic, and the results of water in the mold are an instantaneous boiling which amount to an explosion of molten lead. A face shield or a barrier of some kind are a good idea.
     
  11. rwatson
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    rwatson Senior Member

    Lead melts at 330 degrees C
    Aluminium melts at 660 d C

    I wouldn't have recommended a technique that doesn't work, and hasn't been proved in practice.

    Dont bother trying melting lead in heavy steel containers - it just soaks up the heat needlessly, and the lead stays solid
     
  12. rwatson
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    rwatson Senior Member

    Wood with lead inside is fine. The heavier the better, though too big is awkward. But its not weight only. Get some 'non slip rubber' sheeting for the feet. Often the grip on the surface is as important as the weight in some situations
     
  13. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Soup cans and they will hold anything you'd like for weight, though lead and/or spent atomic reactor rods work best. My first set was cat food cans, because of their low profile.
     
  14. swan1
    Joined: Apr 2014
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    swan1 Junior Member

    All good here indeed , hoping those sheer lines come nice and easy. "Muchas gracias" to all.
     

  15. bob perry
    Joined: May 2014
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    bob perry Junior Member

    Swan:
    I have a big bucket full of spline weights. If you go to my blog:
    http://perryboat.sail2live.com/
    Just type in "spine weights" in the search window. There are two entries on this.
    There is a blog entry done about a year ago where a bunch of us posted on our collections of spline weights and other old design tools.

    I had a 16 year old intern, Will Porter, here for 16 days a couple of months back. I had Will start work with a hand drawn set of lines. He really enjoyed the experience drawing by hand. I figured he wasn't going to get it anywhere else. We moved to the computer after 2.5 days but I thought having some fun bending a spline would be good experience for him so he understood how curves work.
    [​IMG]
    [​IMG]
    [​IMG]
     
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