Coosa vs Nidacore

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

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  1. kpiazzisi
    Joined: Oct 2010
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    kpiazzisi Junior Member

    Here are some preliminary results of my experiment. Keep in mind I did this in a hurry and did not pay much attention to craftsmanship, correct mixing ratios, etc. Already 30 minutes after layup the poly is proving strong. I am sure all you nasayers will find fault with my methodology. I am sure it is much easy to do that then admit that poly can be used to create a bond. Anyway here are the PICS.
     

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  2. kpiazzisi
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    kpiazzisi Junior Member

    Now holding up 90lbs. No sign of failure anywhere
     

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  3. War Whoop
    Joined: Jun 2003
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    War Whoop Senior Member

    Kp Right on repairs Polyester or VE, we have a tendency to be oversold on resins,remember where Epoxies are concerned there is NO chemical interaction only mechanical lock secondary bond,with the esters you still may have some molecules (bond sites)with an affinity for each other, this stronger chemical bond plus the 36 Grit anchor pattern adhesive bond.
     
  4. kpiazzisi
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    kpiazzisi Junior Member

    It finally failed after holding up 140 pounds for a few minutes. Keep in mind this is force being applied directly on the side of the stringer, so there is leverage involved. Had I suspended the whole thing to a beam on my garage ceiling, I probably could have lifted 3 times the weight. The fairing compound I made also never hardened, so that also added weakness. The break also had a little bit of the old roving fibers in the new resin side of the break!
     

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  5. kpiazzisi
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    kpiazzisi Junior Member

    Here are the PICs after it finally failed.
     

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  6. apex1

    apex1 Guest

    Do you know what you are talking? Resins? What is Poly or VE in your opinion? No resin?
    As a pro you should use the right terminology and not amateur drivel.

    You are right that there is no chemical bond with Epoxy, just a several times better secondary one, thats it.
    But there is definetively NO chemical bond with poly either. Once cured is cured, over.

    Let this stubborn chap go for poly, who cares.......... And support him on his way, it is at least not your money he wastes!:mad:
     
  7. War Whoop
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    War Whoop Senior Member

    Polyester Is what I said. or VE = Vinylester ,Now a Wiley Coyote Super Genius such as yourself should know that!!!!!!!

    also you are Dead wrong as usual on THE bonding in Polyester and Vinylester both, if there are any "unbound styrene bonding sites present" which create very strong secondary bonding DUH Now that said unless someone Post cured the laminate at the boiling point of water for 12 hours or so these friendly Molecules will be present. And BTW your water migration in structural Foam is a hoot I got a laugh out of it as well. I usually get paid to educate dummies.
     
  8. apex1

    apex1 Guest

    Go try with yourself!

    And what is Poly or VE in your opinion, to repeat my question? No resin?

    You "professional" made a distinction between Poly / VE and "resin". So whats "resin" ? Epoxy?




    They are ALL resins Mr. Coyote!

    Of course you laugh about water ingress. You have to sell your stuff. Maybe your customers have it harder to get the same fun out of it after some years.
     
  9. War Whoop
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    War Whoop Senior Member

    What Water ? Maybe in the crapola you use one could find pools of water.Your Resin reply is about what I expected from the beer garden ,they are all resin, the "A" side of the Epoxy, the polyester and the Vinylester also the modified epoxy sold by Ashland chemical is a vinylester as well. Are you always this damn stupid or a special effort today??
     
  10. apex1

    apex1 Guest

    Leave it.

    It is senseless to talk with such a sad individual, and I do not waste my time with ****** like you.
    Build your shitty junks like I build mine, but don´t talk a amateur in a crappy repair job.

    You are slippery not only when wet..............

    over and out
     
  11. War Whoop
    Joined: Jun 2003
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    War Whoop Senior Member

    I see the one who builds mis-batched slow azzed Junk here, some advice Wiley work on the reading comprehension, you might even be able to read a label one day and not mix paint in the resin.Sorry about your lack-of-brainpower thing. Gosh, that must be hard to live with.



    Epic Fail Wiley!!!!!!!!!

    [​IMG]
     

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

    kpiazzisi

    Some guys have a lot of true experience with real materials on real boats. I'm part of them...Such a work with marine plywood and epoxy resin on a small boat like yours results cheaper (yes! when you include the work and the time spent...) and faster because it's far simpler. And it has proved to be strong and long lasting since forty years.

    But let's go practical: You have some CSM, your Nidacore and polyester resin. Make your panels in polyester it will be strong enough for your boat. I do that all the time, it works.
    Ask Nidacore, their technical steff is very friendly and helpful. Give them the width or your deck panel so they can help you as it's not necessary to make a tank's armor but just a deck for a small boat.

    With 3/4 of inch nidacore ( as I have seen in the pics) 24" center beams is a bit too much apart; or you'll have to put a lot of glass and resin to get it rigid or your deck will be to flexy with possibility of fracture at the beams. 18" would be more conservative and will use less material: the purpose is to limit the flex at max load (two big guys just between the beams so about 400 pounds) to 1/120 of 18 inches so grossly 1/8 of inch.
    A true rigid deck has a max flex of 1/360. But on a personal boat 1/120 is acceptable, but flexy.
    The local strenght is given by the ability of the panel to withstand one 200 lbs guy on the tip of one foot without local crushing.
    Nidacore has surely tables for that.
    The mat looks rigid because is full of resin (only 25% of glass at best, more likely 18 %) and thick , but the modulus is very low and it's not strong. You have to use roving, UD, biaxial or triaxial to get strength and minimize the quantity of resin which only purpose is to "glue" the fibers together, nothing more. Polyester resin has a very low modulus and is fragil: it breaks easily with little elongation. A good common glass fiber composite has at least 35% of glass, 40-45 % is better.
    Do not forget that GRP with polyester ages fast (becomes soft) and absorbs water (which worsens further the softening) so it will need a water barrier as a gelcoat, or epoxy resin and or paint. That adds weight but it's mandatory.
    Why to use epoxy resin for gluing?
    1-polyester resin does not glue on old polyester, I mean fully cured. It bonds on "fresh resin" but after about about 1 day this bond it's not possible any more. The problem is worsened in the common polyester resins because these resins are PARAFFINED (or they will remain sticky as the humidity of air inhibits the curing of polyester) Nothing glues on paraffin, and when sanding it contaminates the surfaces. With paraffined resins it only possible to glue fresh on fresh while laminating. After 15 x jelly time you have to sand, as the paraffin has migrated on the surface. Epoxy resin glues without problem on polyester, after sanding. Epoxy gluing qualities are far superior to polyester.

    2- Polyester has little elongation. It's means that in all the points of concentration of stresses (ie bulkhead on hull) it will break with very little movement. A good epoxy has 5 % of elongation and better modulus.

    3- At final gluing with epoxy is easier has you have less hard surface preparation, less material and more time to do the job. And thr joint is stronger and will accept flexing without breaking.

    Preparation of the surfaces, specially the hull is primordial. Clean with an industrial degreaser and rinse well. Grinding with with a 4 inch grinder and a metal grinding disk is the faster way (but brutal, be careful) leave the rough surface to get teeth for the gluing. Grind just through the gelcoat. Use a vacuum cleaner to clean. DO NOT WIPE WITH ANY SOLVENT, it may redissolve the paraffin of the remaining dust and contaminate the surface.

    It exist a lot of manuals describing the making of GRP composites, and gluing with epoxy of the bulkheads and floors with the due precautions, specially with honeycombs.

    Let me know if you need some light on this chapter.
     
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