Coosa vs Nidacore

Discussion in 'Fiberglass and Composite Boat Building' started by rlilley, Jun 13, 2010.

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  1. Ilan Voyager
    Joined: May 2004
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    Ilan Voyager Senior Member

    Hi kpiazzisi . Your panel looks good. You do not need vacuum with polypropylene honeycomb as it has a polyester screen hot welded to the cells. So a simple contact between the screen and the glass fiber with fresh resin is enough to insure a good bond.
    The lone precaution to take is about eventual bubbles.

    As you have wisely consulted the tech at nidacore, simply follow their procedure for gluing the bulkhead to the hull. The key of the success is a good decontamination and sanding of hull that will receive the gluing part until the first coat of fiberglass.

    After seing your panel, no doubt you'll do your reparations without problem.
     
  2. apex1

    apex1 Guest

    A widespread error, but a error.

    Polyester (what you call "boat resin") does NOT stick well to cured polyester, and should never be used for such repairs. Use Epoxy (is a resin also!)
    I hope for you, you will follow this recommendation, and not remember my words when your bulkhead pops apart from the hull! (which definetively happens sooner or later)

    Regards
    Richard
     
  3. keysdisease
    Joined: Mar 2006
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    Location: South Florida USA

    keysdisease Senior Member

    Coosa

    Coosa board is a direct plywood replacement, handles and cuts and shapes easily with wood working tools. Fastens very nicely.

    For someone without GRP skills who wants to save weight and doesn't mind the cost its a very good substitution. If you want it to last for the next three owners slap a coat of epoxy resin on it, otherwise as an interior floor leave it as is and it will be just fine and last longer than the plywood you took out.

    As mentioned, Nida Core is a good product but for fastening there will be a learning curve.

    Coosa is used by lots of boatbuilders here in Florida, I'm not familiar with any real failure problems.

    Steve


     
  4. Ilan Voyager
    Joined: May 2004
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    Ilan Voyager Senior Member

    Dear Richard,

    You're preaching in the desert. Yes the bulkhead will pop as fresh polyester does not stick on an old polyester laminate, but a lot seem to like the smell of this resin. So let them use the ordinary and wrong procedure, a lot of sanding until arriving on the fiber itself, twice the surface to sand, twice the material to use, a candle to some saint with a little prayer (that may help and does not cost too much) and no savings at final.
     
  5. kach22i
    Joined: Feb 2005
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    kach22i Architect

    From what I've seen and read on the Internet all the vacuum bagging would do is suck some of the extra resin out thereby making the panel even lighter.

    The vacuum bagging also insures full saturation of the glass fibers, but so does pushing in the resin with a roller for the most part.

    I have never vacuum bagged myself, but have seen it done in person by others.
     
  6. kpiazzisi
    Joined: Oct 2010
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    Location: Sarasota Florida

    kpiazzisi Junior Member

    R U people seriously saying that Polyester Resin can not be used to create a secondary or mechanical bond with old polyester laminate? Seriously. What data do you have to back this up. I have a boat repair friend who has been repairing boats for 25 years with nothing but polyester boat resin. He has not had a boat come back yet. Just to satisfy my curiosity I am going to conduct a test. I am going to laminate a piece of honeycomb board I just made to an old piece of roving attached to a bulkhead I removed. My guess is that the failing point will not be the mechanical bond, but somewhere else. If my hypothesis is correct I would ask that you either supply data for your argument or stop giving out bogus info.


     
    Last edited: Oct 16, 2010
  7. keysdisease
    Joined: Mar 2006
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    keysdisease Senior Member

    Be sure you grind the old surface before bonding to it. This will do several things like rough up the surface for a better mechanical bond and clean it of contaminents and wax. The bond will be mechanical, not chemical as in a wet layup and as with all thing boat, its all in the prep.

    Steve

     
  8. apex1

    apex1 Guest

    You turn barefaced Dude!

    Yes we say in all seriousness that polyester sticks to nothing! Not even to polyester. Except the latter is uncured.

    What your friend does is just cheap jobs, thats it. And his claims to have no reclamations mean nothing.

    Ahh, FWIW
    you actually bark up the wrong tree here with Ilan and me.

    Go, do your crappy job and be happy................

    As Ilan said, in the end you will not have saved a penny, but quality.

    no regards
    Richard
     
  9. kpiazzisi
    Joined: Oct 2010
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    Location: Sarasota Florida

    kpiazzisi Junior Member

    Where is your proof. So far all you have provided is an opinion. I am willing to listen and be open minded, but so far you have just provided sarcasm. Please provide me with a reputable link. Yes, there is plenty of literature that states that epoxy is a better adhesive. There is also literature that states that epoxy is a better sealer. I am sure epoxy is a superior resin, however I can not find literature that states that poly will not work as a repair resin to bond new poly laminate to a fully cured poly laminate. If you can find this information from a reputable source, then please provide me the link and I will go out and spend at least $150.00 for a 3 gallon kit, and hope that's enough to bond my stringers/bulkheads into the cured poly hull. I will be at this stage soon, so please find me the link if you can.

    I will probably conduct my test tomorrow, if so I will post the results.

    Sincerely
    KP
     
  10. tunnels

    tunnels Previous Member

    Nida core works well with Vinylester resins , poly is ok just vinylester is better also for your tagging to the boat!. Use a stitched matt rather than a woven uses a little less resin for the same weight of glass and makes a better job smoother job !
    If you are sticking wood any where then yes go for epoxy and bag it lightly !! dont squeeze hell out of it .Bagging takes the guess work out and gets rid of those pockets of bubbles and spreads the resin better under what you are sticking down . Not perfect but better than placing a ton of weights on top and ending up with indentations all over the place .:D
     
  11. tunnels

    tunnels Previous Member

    Wow Richard thats a bit harsh !!dont lay those kind of words on the poor guy !!
    I have seen in some of the posts you have and there is a sense of humor now and then , i even had a smile after reading what you had written . back up a little and take a breather !!
    You have some strong beliefs and you have a lot to share but everything works just some works better than others !!So tell him why and dont get all shitty about it !
    Take a deep breath and write !!:D
    Yeah its me and im back !!
     
  12. apex1

    apex1 Guest

    The expertise of our skilled members and the common knowledge of the entire industry is more than sufficient proof.

    Polyester does not stick proper to anything! period.........

    Of course one can work with a much larger surface, chemicals and half a dozen tricks to get some sort of a bond. But in the end one has the same, or even higher cost, and a far inferior result. VE, as recommended by our best proven amateur, is even worse for this application........

    But what am I doing here?
    :?:
    Ilan got it right:
    Go, do your job.

    Best luck.
    Richard
     
  13. kpiazzisi
    Joined: Oct 2010
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    Location: Sarasota Florida

    kpiazzisi Junior Member

    Thank you Tunnels. I am not trying to get into a pissing contest with anyone. I just want to fix my boat. Fiberglass composite isn't my lifes compassion and I am not building a race hull. I agreed that epoxy is superior and Apex1 agreed that you can get some sort of bond if you prep the surface and use proper technique. His "Some sort of Bond" is probably adequate in a 18 foot ski boat for many of years. So I don't think we really disagree that much.

    Anyway, can I PLEASE get some help! No matter what I need more resin anyway. I used almost 4 gallons to make 2 4x8 sheets of laminated nida. These two sheets are enough to cut out my bulkheads and stringers. This was new construction material so the CSM I laminated to the Nida with Poly should be OK....correct?

    I am now thinking of buying epoxy resin to tab the bulkhead/stringers into the hull. I eventually will need more resin and the epoxy is better for bonding. I found a guy close to me that sells epoxy in 1.5 gallon kits. I will provide the link. Can you tell me if this epoxy is OK?

    For the deck I will need three 4x8 sheets of Nida. I have about 60 yds of CSM on hand. I am planning on buying another pail or two of Poly and using CSM, Poly, and then a cloth on the deck. Since the deck will use a lot of resin and it's new material I can save a lot by using Poly (Is this OK?) I can tab the deck into the hull with epoxy if necessary? I would like to Gel Coat the deck, so the edge that's tabbed in with epoxy may have an issue accepting the Gel Coat? I believe most of the edge is not seen anyway once the interior side panels are installed.

    http://cgi.ebay.com/ebaymotors/ws/e..._trkparms=algo=LVI&its=I&otn=2&category=26455
     
  14. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    I agree to Apex, poly's secondary bonding to very poor thats not an opinion its a material fact.
    Hence the comment about building a boat from new versus a repair.
    Do some research.
    Vinylester is better
    Epoxy is the best
     

  15. apex1

    apex1 Guest

    Bateau.com sells a relatively cheap "Silvertip" epoxy, look that up.

    You should not use (and must not, with Ep) csm when the structure has to bear some load. Use fabric instead. If you go again for Poly on your deck, then of course you must (additionally) use csm between layers and as first layup. You cannot gelcoat Epoxy, and there would be no need anyway! The gelcoat is more or less just a water barrier, not needed with Ep.
    The hull, deck joint cannot be done with poly again. You need either some Ep, or Sikaflex and the like.

    Believe me, you are not saving one single penny with Polyester, but produce a inferior structure and bond.
    For sheathing the bulkhead core panels it was ok to use poly, but thats it.

    Regards
    Richard
     
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