Still at it... (with questions on shaping and gluing blue/pink foam)

Discussion in 'Boatbuilding' started by BobBill, Oct 30, 2020.

  1. BobBill
    Joined: Oct 2009
    Posts: 750
    Likes: 13, Points: 18, Legacy Rep: 157
    Location: Minnesotan wakes up daily, in SE MN, a good start,

    BobBill Senior Member

    Making foam hull from blue/pink stuff using H-16 side as web...

    What is decent glue to use, besides epoxy (too hard);

    And, if anyone has experience using electric wire to shape before fairiing?

    This hull plans to be 16' LOA, 15" beam-give or take, and 15" deep, ssy assymetrical, like Hobie, but about half weight..as outrigger as in avatar rig.

    Want to try the foam gamut...
     
  2. garydierking
    Joined: Sep 2004
    Posts: 154
    Likes: 26, Points: 28, Legacy Rep: 174
    Location: New Zealand

    garydierking Senior Member

    The polyurethane glues work well with foam. Something like Gorilla glue works fine and is easier to shape later. I have cut RC aircraft wings with a hot wire bow that I made. Stainless wire hooked up to an old battery charger. Should be more info on the aircraft building sites.
     
    Rumars likes this.
  3. fallguy
    Joined: Dec 2016
    Posts: 3,527
    Likes: 489, Points: 93, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    I read you were going to build a hull! Amas are fine with polystyrene. Make sure to rough it up with 40 grit and I also like to hotcoat with thickened epoxy immediately before glassing.

    good luck

    I built some Dierking inspired amas
     
  4. KeithO
    Joined: Jul 2019
    Posts: 241
    Likes: 37, Points: 28
    Location: Michigan

    KeithO Senior Member

    Look at the attached link. A video made by Burt Rutan on building the LongEze composite airplane.

    Scroll ahead to the 12:00 mark to look at how they build the hot wire cutter and how they set the wire tension before each cut. Aircraft Spruce may still sell a kit to build these, you just supply the 2x and aluminum tubing...
     
  5. BobBill
    Joined: Oct 2009
    Posts: 750
    Likes: 13, Points: 18, Legacy Rep: 157
    Location: Minnesotan wakes up daily, in SE MN, a good start,

    BobBill Senior Member

    Thanks all...
    Am on borrowed machine and being brief.
    Will view vid later...have to make coffee.
    Bought couple electric train transformers and some wire for trim-bow and using hard edges of shear-web as guides...would put up pics but on problematic machine.
     
  6. BobBill
    Joined: Oct 2009
    Posts: 750
    Likes: 13, Points: 18, Legacy Rep: 157
    Location: Minnesotan wakes up daily, in SE MN, a good start,

    BobBill Senior Member

    Gary, Good on ya...Save me bum again...Gorilla Glue, soft...
    Will try to take pics of my chore, as it goes, especially wire cutting.
    Main hull is 19" so making rigger about same as before, with the 16 Hobie...for the carry...and adding a cockpit to main hull for paddling comfort/easer...also have to add the "jacks" to keep massive sail out of water when doused.

    Also, FWIW, the hook and llop fastener setup works will with smooth carbon spars, just takes some time to fasten sail to spars. Way it has to be with smooth spars...so you know.

    The hook and loop stuff is strong...220 square feet main...no jib yet...have not tried.

    Thing I most look forward to with new hull, outside of lighter weight, is easy float.

    Thanks...will post pics in Spring I am still above ground.
     
  7. BobBill
    Joined: Oct 2009
    Posts: 750
    Likes: 13, Points: 18, Legacy Rep: 157
    Location: Minnesotan wakes up daily, in SE MN, a good start,

    BobBill Senior Member


    KeithO, merci...this is kewl...hot wire is picky but precludes mess. I have save guitar wire and have some Amer Flyer tinplate train transformers and a 110v rheostat - in case.
     
  8. BobBill
    Joined: Oct 2009
    Posts: 750
    Likes: 13, Points: 18, Legacy Rep: 157
    Location: Minnesotan wakes up daily, in SE MN, a good start,

    BobBill Senior Member

    Went to box store to look at the foam sold and have been nudged to Gorilla Glue...very low cost the pink foam and currently 2-inches thick, so easy to useglue up. The biggie now is how to shape with the Hobie-16 asymmetrical side-cut as shear web...
     
  9. BlueBell
    Joined: May 2017
    Posts: 1,326
    Likes: 267, Points: 83
    Location: Victoria BC Canada

    BlueBell Ahhhhh...

    What is this "web..." you keep referring to?
    It would seem you're using it to represent the compound curvature of ama surfaces.
    "Web..." ?
    If so, how are you going to recreate this "web..." form?

    Are you going ahead with this now or is the plan still to wait for spring?
    You keep referring to pictures... can you post some because I'm having a hard time following what your doing, saying, talking about.
    Cheers
     
  10. BobBill
    Joined: Oct 2009
    Posts: 750
    Likes: 13, Points: 18, Legacy Rep: 157
    Location: Minnesotan wakes up daily, in SE MN, a good start,

    BobBill Senior Member

    "Shear Web" is a stern-to-bow stiffener and thick or rigid surface to which the foam sheets are attached.
    It also anchors pylons and attachments like a stay, chainplates, or even decking set atop it.
    Often, simply thin (3/16 or 1/8 ply, cut to outrigger's outlined/planned shape.

    (Am using spare machine and doubt pics are here.)
    In this/my case, am using side of Hobie 16, the the starboard or flat side of the starboard hull, which will double as shear web and cutting guide, might add storage area...Do on-line search for "foam outrigger build" and should find them in various stages of construction. I think Gary Dierking's foam outrigger is on display as well, but it is fashioned of Dow (blue) construction foam..and glassed.

    Glassing the faired foam affords somw stiffening and protection, with ability to repair, if nec.
     
    Last edited: Nov 24, 2020 at 6:22 AM
  11. fallguy
    Joined: Dec 2016
    Posts: 3,527
    Likes: 489, Points: 93, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    I don't love the idea of reusing the Hobie hulls, but I miggt not get it.

    the pylon reuse is good, no great, but if you are using the top of the Hobie hull; that is not really a shear web per se. More of a cap, no?
     

  12. BobBill
    Joined: Oct 2009
    Posts: 750
    Likes: 13, Points: 18, Legacy Rep: 157
    Location: Minnesotan wakes up daily, in SE MN, a good start,

    BobBill Senior Member

    Do not plan to use of H-16 top as deck, only side as shear...
     
    Last edited: Nov 23, 2020
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.