NidaCore vs. Plywood

Discussion in 'Downeast Projects and Boat Building' started by powderpro, Feb 24, 2012.

  1. powderpro

    powderpro Captain

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    I performed a test; NidaCore vs. Plywood for my own information, but thought I would pass along my findings. I had no other reason for doing the test than for my own personal information. I think some of you will find this information interesting.

    Test parameters: Both core materials measured 18" x 48". 3/4" thick NidaCore vs. 1/2" marine plywood.

    The 3/4" NidaCore was covered on each side with 1-layer of 1708 and then 1-layer of .75 oz mat. The mat was used to cover the 1708 to create a smoother finish.

    The 1/2" marine plywood (no voids, good stuff) was covered on each side with 1.5 oz mat. The mat adds very little if any strength, but it is what I use to seal plywood in bulkheads.

    The weight difference between the 2 finished materials equated to 15 lbs per 4'x8' sheet. So if you were to use say 30 sheets of 4'x8' 1/2" plywood to build your boat, you would save 450 total pounds by using the NidaCore instead of the plywood. Those sound like good weight savings, but it gets better.

    The NidaCore was way more rigid and stiff than the plywood (which surprised me a little bit). For plywood, marine plywood with no voids is pretty strong/stiff material. I've always been satisfied with it's strength. I'm just estimating here, but I would guess that you would have to jump up to at least 5/8" marine plywood to equal the rigidity/strenth of the 3/4" NidaCore. 5/8" plywood is about 11 pounds heavier per 4'x8' sheet than 1/2" plywood, so now the weight savings for a 4'x8' sheet of NidaCore is about 26 lbs lighter than a 4'x8' sheet of 5/8" plywood. 5/8" marine plywood is sturdy material in my opinion, but the NidaCore blows it away in weight savings.

    I'm not trying to say that NidaCore is superior in every way, or that you should use NidaCore in all your builds, projects, repairs, etc. But when you simply look at weight, I'm estimating a 600 - 1,200 lbs weight savings on a typical 36'-38' boat if you use all NidaCore vs. all plywood. There are a lot of variables in exactly how much weight you would save by using NidaCore, but I think a 600 - 1,200 lbs savings would cover most DE boats in the 36' size range. The bigger the boat, the more weight savings; smaller boat, less weight savings.

    For the way I build my boats, I'm estimating a 600-700 lbs saving. I'm estimating the extra material cost for me will be about $3,500 more to do all NidaCore vs all plywood. And obviously some more hours of labor for the NidaCore.
     

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  2. Tunascapes

    Tunascapes Senior Member

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    Thanks for sharing. Everyone always talks about weight savings but it is nice to see it in actually data you can use. I just made a sandwich of 1/2 and 3/4 that is four ft by 5 ft and burst out laughing when I went to pick it up. I was crazy not to use a composite for it but with the labor I have in to it I'm not changing it.
     
  3. F/V First Team

    F/V First Team Captain

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    I think I'll stick with Tricel
     
  4. powderpro

    powderpro Captain

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    Tuna- you sandwiched 1/2" and 3/4" plywood together? That's a lot of material... I think your plywood could stop a .50 caliber :)
     
  5. Tunascapes

    Tunascapes Senior Member

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    Ha. I was trying to build up so I could get a 3/4 hatch thickness so they could be stood on no problem. Probably over kill and I'm sure there were other ways. Oh well the bow will stay trimmed down.
     
  6. powderpro

    powderpro Captain

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    I didn't start this thread with the intention of starting a back and forth on which material is the best, or which material beats all others. It was purely a weight comparison/experiment.

    But since you mentioned Tricel, why do you prefer it over other available materials/products? Cheaper? More readily available? I can get Nidacore easily and at a good price, so if I built with composites, I would probably use Nidacore, but I'm not against looking into Tricel or other products. Thanks
     
  7. F/V First Team

    F/V First Team Captain

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    [​IMG]


    I like being able to have a sheet of material 4' x 8' that is 3/4" thick that I can bend in a tight radius and have an exposed wood grain face. Oh and it weighs 18 lbs per sheet.
     
  8. jawz

    jawz Senior Member

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    big fan of composites - i use alot of penske board - great product,lite in weight and strong !
     

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  9. MDI45

    MDI45 Captain

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    Travis,i thought u guys used very thin veneer in tonys boat
     
  10. F/V First Team

    F/V First Team Captain

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    Not at all, they came 3/4" thick and with a little boat shop magic we got them to do amazing things :)

    Finishing up a project with Coosa board, same as Penske but a bit more economical. I would definitely use it again, although I wouldn't pick it up without gloves on.
     
  11. powderpro

    powderpro Captain

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    Is Coosa board easy to work with? Easier than Tricel or NidaCore? What are the advantages/disadvantages of Coosa vs. Tricel or Nida? My experience with NidaCore is pretty limited, but I feel comfortable using the stuff on a large scale project. Just trying to compare other products and how well they work vs. plywood and NidaCore. Thanks.
     
  12. F/V First Team

    F/V First Team Captain

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    Coosa is very easy to work with, I thought it would buck against the saw blade something fierce but it just went through it like butter. Very easy to saw, the dust kind of sucks though, so you know, wear a mask. Easy to shape with a grinder for doing radii of different degrees. I would certainly use it again. Wear gloves when handling the sheet goods though, all those little shards of glass like to find their way into your skin and are a pain to track down and pluck out.

    As far as how it is against Tricel, well it is heavier and I don't think that I would be able to contort it like Tricel. I might try it with a piece of scrap after this project is done so that would be a disadvantage in regards to Tricel. It isn't made out of the same material as nidacore (recycled milk cartons) so I am not worried about delamination as much (that's why milk jugs were popular to mix resin in back in the day - because the resin didn't stick to the plastic and you could just pop out the hard puck and reuse the jug, also: it had a handle). Also don't have to de-core the Coosa as one would with nidacore and Tricel for most applications so that would be an advantage. I haven't tossed any Coosa into a bucket of water to test absorption yet, but for all I know it might be hydrophobic (which would be a plus) so I really cannot comment on that. The price is a turn off in regards to plywood, even to Tricel actually, but it is fairly rugged stuff. Takes a shot pretty nice when one is bored in the shop after hours and has access to things that fire projectiles. One might try it again on a piece of scrap with no glass on it for a proper comparison. The 1/2" material of the 15 lb density is what I've been able to work with so far, it has the same bending properties as a sheet of plywood at those dimensions, it might be a little more limber, so putting some glass on both sides of the material would help this obviously, just to stabilize things a little more. The way Coosa is stored is important as well, having it leaning against open air because it's propped up in a trailer at an angle isn't the best, they can get a little bow to the panels - plywood can do the same thing. On smaller projects this wouldn't be a big deal, you can use that to your advantage or alternatively hide the arc in the way that you build the piece. Coosa takes a screw pretty dang good for just being injected foam in a 3 dimensional fiberglass lattice. But you can over-torque the screw and tear it out, something plywood is apt to do as well when using it as end grain. It's good stuff, might not be the best for every thing, but I'd consider using it again.

    Use some imagination and you can use all kinds of different materials for construction.
     
  13. BillD

    BillD Captain

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    Good description of materials!
    Thanks
     
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  14. powderpro

    powderpro Captain

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    First Team- Thanks for the informative response. You have said before that you prefer Tricel over NidaCore... besides the option of having a veneer of wood grain on the Tricel, isn't Tricel and NidaCore about the same thing? They look very similar, almost identical to me. Thanks
     
  15. F/V First Team

    F/V First Team Captain

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    nidacore is recycled milk jugs that resin doesnt stick to situated in a hexagon shaped honeycombto make the thickness of the panel

    tricel is resin impregnated kraft paper core situated in a triangular pattern to make up the thickness of the panel. surfacve options range from nothing (just the kraft paper core itself) to wood panel exterior, to plastic exterior to various flavors of metal.

    nidacore has to be laminated to make panels, tricel comes as a 4x8 panel that has to be cut to fit.

    bare coosa board takes a shot well, tested it out this morning and there was minimal damage to the core.
     
  16. benenglish76

    benenglish76 Member

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    I was always under the impression nida-core was best handled in a pre-preg process...
     
  17. F/V First Team

    F/V First Team Captain

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    Getting equal pressure on the core is key, vacuum bagging is very good at this. If you have a method to do so in a press format without bagging, it should work similarly.
     
  18. jawz

    jawz Senior Member

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    coosa/penske board - great products...but,penske and coosa do not hold screws well - granted,these will hold a screw better than divinycell,but,if you're planning on fastening anything,you really should remove the coring in the area the fastener's gonna go,and fill it with epoxy...if you're gonna thru bolt something,that area should be sleeved...

    penske/coosa board will not absorb water...another good point regarding composites,is the fact you really don't need to use epoxy to laminate,using vinylester products is fine.

    and yep,gotta wear a mask and saftey goggles when cutting with a saw - it really does cut like butter,saw will never load up...

    i do not like,or use nidacore,for anything...people who have never seen it before are amazed when i show them a piece of it - the reaction is allways the same "that's it " ?? it's basically cheap shit,in plain words,i would never use that for decking,i know some mfg's do,but some not me.a few years ago,a company sent me a sheet of it,with an order i placed from them - told me to "try it out" - it's been collecting dust for a few years now...


    marine grade ply is fine - strong,and holds a screw well - drawback,it rots...rotting is usually caused by poor sealing - balsa turns to saw dust,and plywood rots - keep it dry,and there's not a problem,get it wet - things change,and change quick too...
     

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  19. F/V First Team

    F/V First Team Captain

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    I have that exact same sample panel of nida-core collecting dust...
     
  20. F/V First Team

    F/V First Team Captain

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    Any screw location should be treated as any other core material would be with back filling and a bedding compound or adhesive, but the glass on that panel is what should be holding the screw, not depending on anything beyond that. I was impressed that the panels held together well when screwed together with a coarse thread, you could really tighten them up to take the bows out of the panel (seriously, don't have them stored upright leaning against the wall) but like anything foam they can (and do) tear out when you torque them up too much. But that's why we putty things, so that we don't have to rely on fasteners in the final piece.

    No idea if these panels would lend themselves to something like stitch and glue method, the wire might eventually cut through them if there is enough pressure. Might have to oversize the hole and put a sleeve or something in the hole prior to the wire, like some tubing or the like. Might be interesting.
     

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