Styrofoam

Discussion in 'Fiberglass and Composite Boat Building' started by Chukchi, Oct 27, 2013.

  1. Chukchi
    Joined: Oct 2013
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    Chukchi Junior Member

    I've been trying to build a floating rest platform for spearfishing. I often will dive off the beach and a cooler, as well as a resting place, would be nice! I've tryed PVC pipes like a tiny catamaran (4" and 6" diameters) but it's just too heavy. My next try will be with styrofoam, eps from home depot. Is there anything out there I can paint it with to withstand the bumps and bruises of waves and rocks?
    Thanks!
     
  2. El_Guero

    El_Guero Previous Member

    Shape it reasonably well in the form of a big surfboard (or sit on top kayak), leave room for your cooler in the middle (and live well), wrap in Dacron and epoxy .... Top the cooler .... and have ice for 7 days.

    :)
     
  3. PAR
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    PAR Yacht Designer/Builder

    Why would you "wrap in Dacron"? Why a surfboard?

    Calculate the amount of weight you would ever have aboard this float, then multiply by 2, for a reasonable margin. Shape as desired, but if just a platform a rectangle is about as good as it gets. Cover in light 'glass cloth and epoxy, then paint with color of choice. If you expect a lot of traffic on top of this platform, use a 1/8" or 1/4" piece of plywood on top of the foam, which gets 'glassed in when that time comes.
     
  4. El_Guero

    El_Guero Previous Member

    Chukchi

    Update us when you get some pictures.

    wayne
     
  5. Grey Ghost
    Joined: Aug 2012
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    Grey Ghost Senior Member

    Is the idea to heat shrink the dacron on the foam or ???

    Does dacron bond well with epoxy??
     
  6. El_Guero

    El_Guero Previous Member

    Shrink wrap ... epoxy, just because I like epoxy for its strength.

    Paint will do.
     
  7. PAR
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    PAR Yacht Designer/Builder

    Epoxy alone, without a fabric reinforcement has little strength. Paint is just a UV protection coating, so . . .

    Maybe a little better definition of what you'll do with this craft would help.
     
  8. Chukchi
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    Chukchi Junior Member

    Wow! Lots to think about! Thanks!
    The platform needs to be tough to withstand being thrown into the back of pick up trucks. And being dragged through sand, rocks and the occasional oyster bed. Stability is needed also, so I don't overturn it putting a fish in the cooler or hanging on it to rest.

    How thick should the foam be? I've read that one cubic foot will provide Buoyancy for 62 pounds, but how much of the foam is above water?
     
  9. PAR
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    PAR Yacht Designer/Builder

    A cubic foot of foam will be just flush with the water's surface with a 63 pound load, which is why I recommended you double the flotation requirement.

    You can toughen up the foam with xynole or dynel, though only in regard to abrasion. It'll still be moderately flexible, which may not be a bad thing for this float. You can sheath the foam with 'glass cloth, which will stiffen it up and add abrasion resistance. There's other choices as well.

    How much weight will it need to support in the worst case situation? How heavy can it be? Do you want any features, like a built in beer cooler, automatic oyster shucker, etc.? Do you want to stand on it or will scantly clad young ladies, be relegated to a lawn chair instead? Will it be propelled? If so, by what? Any thing else you might want to add, regardless of how innocuous it might seem, it'll probably play a role in the float's shape, size, etc., so don't be shy.
     
  10. Saqa
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    Saqa Senior Member

    I have done a styrene craft before and I can relate to what you want to do. Since you are thinking of a cooler too why not make them one. Get a block of styrene foam, give it a barge type shape so you can lay on top and paddle or push with your fins. Use a hole saw as a router blade and dig a cube type cavity. Once you have given it a skin with some fabric and made a lid with a bit of foam sheet you will have your platform and cooler in as one unit. Drain out on landing and transfer to a regular type cooler back at the car. No reason why you cannot fit some good barrow type wheels to it too and make it easy to drag back to your car. Lots of people use a block of styrofoam in fiji for net and spear use
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  11. SukiSolo
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    SukiSolo Senior Member

    Here in the UK there used to be available a small dinghy built out of expanded polystyrene. Called a Puffin it was clad in cloth with something that held it on without melting the core. They were blue and took a small outboard and were used as tenders. The weakness was if the covering got a hole then a solvent could enter the core and eat it away.

    They were not durable long term but were light and stiff. Funny little things I remember rowing them and using them with motors at one time. Sort of a late 60s vrsion of the Fairey Duckling but much smaller.

    Hoping this image works.

    http://www.the-broads.co.uk/fileattachments/j/june13_056.JPG
     
  12. SamSam
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    SamSam Senior Member

    Yes, why wrap it in a peel ply?

    It's another example of elguero's lack of knowledge and inability to keep quiet. He has no real answer but has to give one anyway.

    On the one hand the erroneous info he gives is a waste of time and effort, confusing people that want answers, and on the other hand it can be dangerous to propose solutions that might leave people in danger when they don't work.
     
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  13. PAR
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    PAR Yacht Designer/Builder

    I'm glad I'm not the only one that's noticed this attribute, maybe another can join me on your "Ignore List", El_Guero .
     
  14. Grey Ghost
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    Grey Ghost Senior Member

    The only thing I've read similar was a Duckworks article on covering a SOF with a second skin of xynole+epoxy: http://www.duckworksmagazine.com/07/howto/skin/ Dacron was heat shrinked over the skeleton and then a "second layer" of xynole was laminated with epoxy on top.
     

  15. jonr
    Joined: Sep 2008
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    jonr Senior Member

    If you want "drop it on the rocks" durability and don't mind a simple rectangle (unless you can roto mold), then consider foam filled HDPE.

    Saqa's work looks nice.
     
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