Polycore

Discussion in 'Fiberglass and Composite Boat Building' started by Meanz Beanz, Feb 12, 2008.

  1. Meanz Beanz
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    Meanz Beanz Boom Doom Gloom Boom

    I have read some interesting things about polycore re strength and cost. What I would like to know is...

    1. How you would go creating complex curves with it, can it be stripped, bent etc.

    2. Do the ends present any issues when joining, creating apertures etc. Do you need to fill?

    Anyone used the stuff? What did you think?

    Cheers
    MBz
     
  2. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    The little I know about Polycore is that it is another polypropylene honeycomb core product. I'm assuming it comes with a scrim and I know it can be had with metal, wood or other faces bonded to it.

    It's a "sheet goods" product for the most part, though I suspect you could permit some cellular distortion with sufficient sheathing thickness, it'll act like all sheet goods and need conical or cylindrical development, as any panel would.

    I haven't tried diagonal planking the core, then sheathing, though I would think it's possible, so you could get compound curves. I would also surmise you could cut planks from the material, much like carvel, then sheath to get compound curves.
     
  3. Meanz Beanz
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    Meanz Beanz Boom Doom Gloom Boom

    So far I have had suggested that heating and bending is possible with in certain limits and beyond that a double diagonal method is used, this seems to be dependant on the strength required. Apparently the thinner lower strength sheet is used to do this sort of work. Edge joining is to be avoided because of problems gluing the poly so I imagine that sheet joining is done with a butt joint relying on the laminate strength. I have wondered if an interlocking saw tooth pattern might be a way to go. It seems quite light at 80kg cubic meter, I don't know how that compares with cedar and foam but I must do that comparison.

    It has a 45gsm fiberglass scrim, in the high strength product this prevents something like 99% of resin adsorption by the core.

    So yes your educated guess seems close to what I have been told so far but they don't recommend stripping it "carvel style" because of the edge gluing issue.

    I have yet to find someone that has bent it or built a complex shape with the stuff, hearing about actual experience would be great.

    Cheers
    Mbz
     
  4. Roly
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    Roly Senior Member

    WesternCedar = 380Kg/m^3
    Foam from 30-->150kg/m^3
    I am interested in the possible application for furniture.
    I think it is approx. 2/3 the price of 80 kg foam.
    Don't like the idea of polyethlene and resin though.
    Is the scrimm attachment done when the poly is liquid?
    I might just bite the bullet and use foam.
     
  5. Meanz Beanz
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    Meanz Beanz Boom Doom Gloom Boom

    The scrim is somehow attached in manufacture so the idea is that the resin never hits the polly. I'd assume its some sort of heat weld attaches the scrim but I don't know. I have heard of amazing stories of strength i.e. 4 ton truck driven over test panels with no damage, serious hammer bashing with very little damage, boat dropped from about 30' in an intentional effort to break it (after insurance write off, forget the reason for that) and again the stuff refused to break, in the end they chain sawed it up. Its all hearsay though, I do know of one guy who did a Seawind 24 hard deck, 600 gram fg top, 400 bottom, 15mm high strength panel and he reckons it stiffened the old center console and is a very stiff deck, he seems a reliable witness.

    Thanks for the weights Roly!

    PS. Just found this in an email

     
  6. Meanz Beanz
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    Meanz Beanz Boom Doom Gloom Boom

    The following was found on the www.themultihull.com website in the forum under materials:

    Gidday
    Just an update on my polyprop cored deck replacement on my Seawind 24.
    I managed to beach the boat on Sunday and replace the rotting ply versions.
    It has worked much much better than I expected. The stiffness is way beyond my expectation.
    I bolted on 50mm x 3mm flat aluminium that slots into the original sail track for the tramps.
    I covered it in the same outdoor carpet from the original decks
    There is more flex in the central console than the decks. The result is it actually stiffened the console.
    One other unexpected benefit was that the deck no longer gets too hot to walk on as it did before (the sun is hot here in summer). This leads me to believe it may have some fantastic insulation properties
    Would I build a boat from it? In a flash!
    I'll post some pics after easter of the end result.
    Rgs
    Tony

    G'day Tony

    What thickness Polycore did you use for your decks, and did you add any stiffening webs underneath?

    I spoke to the guy at Polycore in Q'land the other day,and he was very willing to advise... the price of the Polycore was only a little more than I was quoted for the same thickness sheet of marine ply - and a fraction of the weight. You'd have to factor in the weight of the interior f/g too, but you'd end up with a much lighter boat.

    Col.

    As per earlier post(have a look at the first lot)
    Core is 15mm
    600db top 400db bottom
    4 x 34mm pvc tube half pipe glassed over with 400db for webbing.
    If I did it again I wouldn't do the webbing, no need.
    I only did it as insurance because the laminate was an educated guess
    There are some photos of it under vacume on the seawind picture area under "this way up"
    With a little forethought and planning, building a boat out of polycore may be faster and lighter than strip.
    My load test was to have two grown men jump up and down and see how much it would flex. It passed the test easily.
    The guy at polycore was great to me and easy to deal with. Best advice I can give is to try it yourself. Its cheap enough
    Rgs
    Tony
     
  7. PAR
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    PAR Yacht Designer/Builder

    If the core is just a separator that needs to be well bonded to the structural skins, then what's the difference if there are seams in the core material. The sheathings provide the "tie" between core panels. Double diagonal seems redundant to me, you only need one and a well stuck sheath of sufficient dimension.

    In a any boat larger then 8', you'll have seams anyway. I don't see why multiple diagonal seams are any better then multiple horizontal seams (such as a carvel plank).
     
  8. Meanz Beanz
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    Meanz Beanz Boom Doom Gloom Boom

    Re Strip planking : I think its just to do with the fixing and fairing prior to the glass going on. After all you can't really fair it like foam and if its not glueable at the edge you have extra problems forming up. I could see that it would be an inappropriate use of the stuff, although I have not seen it yet. The use of the terms high strength and normal strength suggests that there is some strength in the core. Yes as you say you will have to join sheets, but simple butt joints are going to be a bit easier to pull off than strip planking.

    I hope to get a sample and play with it.

    Cheers
    MBz
     
  9. Roly
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    Roly Senior Member

    "hope to get a sample and play with it."
    Me too. Phoning Hi-mod this moment.
    These are some exciting developements for sure.
     
  10. PAR
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    PAR Yacht Designer/Builder

    I'm not thinking of strip planking dimensions, but carvel or wider, whatever the compounds will permit. On a 25' carvel that has 12 to 14 planks per side the average plank width would be over 5" on a typically shaped hull. Maybe think of it as extreme multi chine without the logs. Diagonal would allow wider planks.
     
  11. Meanz Beanz
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    Meanz Beanz Boom Doom Gloom Boom

    You would just have to be able to match the edges exactly because you can't sand. That's something that you would have to be careful about with diagonal as well. Maybe bagging it would be a good idea.
     
  12. Pylasteki
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    Pylasteki Junior Member

    Hey Guys,

    Been a few months... anyone given this stuff a try? :D

    Zach
     
  13. maggie42
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    maggie42 Junior Member

    The real Polycore come forward!!!!!

    Greetings all.

    I had not realized that this new core has generated so much interest!

    I watched the feeding frenzy at the Sanctuary cove Boat Show on the Gold Coast this year.......when people actually saw the right core!

    Most of the comments were I thought.......I knew....????

    The boat manufacturers were lining up to feel the core and to see the independent DVD impact tests
    and the independant DVD on the new fire rated Polycore!

    And by the sounds of it you all seem to be confused with its abilities and strengths.

    Are you aware that Polycore is the new generation PP core that is actually structural?
    Many do get confused and call the old type of honeycomb cores Polycore!

    I have even seen and heard some sales reps pulling the wool over some of the yachties with trust me this is the real structural Polycore core while waving the old type core under their noses!!!!!

    Look......
    they may look the same but you actually MUST have the two in your hands side by side and you will see, that they are miles apart

    If you have any doubts just look at the panel at each end there is a
    Brand mark...which says's
    Polycore Honeycomb (TM)
    next on the sheet is the manufacturer
    and then the sheet will have its grade... H for HIGH STRENGTH or S for STANDARD core.

    If you want to feel the real Polycore core drop me a line and I will pass you to the right distributors of the core......

    The real Polycore is structural and has passed for full hull core and bulkhead construction with its testing with DNV for non survey vessels!!!!!
    Certificate pending the final stage for surveyed vessels.

    Genuine Polycore is equal to core cell foams and Dviney cell in strength all three will sail you home just Polycore would do it cheaper!!!
    and with impact it was a top score!!!

    Balsa core in impact testing failed badly the DVD of the testing showed the 15kg weight going straight through the Balsa core like it was cannon shot going through butter at the 3 meter mark you saw it fail and leave a hole that no man could plug or bail out to save the boat.

    P.S

    In China there is a trader selling the old type of core, and call themselves Polycore Technologies
    I must make It clear that this company is not a manufacturer and has just stolen the name Polycore.

    There was a lot of talk about it and at the show it was made clear that this company was a leach

    This is one of the reasons why I joined your forum,
    If I can assist people it will make my day!!!!!

    As Multiehulls are my life and 2nd love

    Cheers Maggie :D :D :D
     
  14. tinhorn
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    tinhorn Senior Member

    Ok, Maggie - we expect to hear from you regularly.

    IF it passes impact tests, Polycore sounds great. When I was in the biz (back in the last century) I used some cardboard honeycomb, Coremat, balsa, 2# urethane sheets, and Parabeam. Parabeam was my favorite, and Polycore sounds like it has many of the same advantages. I'd seen a plastic honeycomb core material, but at the time I wasn't convinced of the bonding capabilities of the plastic honeycomb to my vinyl ester resin.

    If it sticks to the resin, this product sounds great!
     

  15. maggie42
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    maggie42 Junior Member

    Hi Tinhorn.
    Thanks for the follow up.....

    check out www.austrol.com.au this will put your mind at rest
    This company has the PP8-H structural core- they are the first to post the DVD of the inderpedant impact testing and the F.R fire Polycore DVD
     
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