Epoxy/Choppstrand mat...??

Discussion in 'Materials' started by kitto, Feb 7, 2008.

  1. kitto
    Joined: Nov 2005
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    kitto Junior Member

    Hey there,

    just wondering if anyone has had any experience with laminating Chopp strand matt with Epoxy.

    I cant see why it wouldnt work as long as the Epoxy was quite viscus.

    Any advice?

    Also, has anyone found a way of laminating over Polystyrene with Polyester resin? I here there is such a thing as Styrene free Polyester resin out there, any idea how i can get my hands on some??

    Cheers Kitto
     
  2. rwatson
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    rwatson Senior Member

    There have been quite a few discusions on Epoxy and relevant viscosity.
    The big question is why you would want to use it on chopped matt. Its very expensive stuff, and the price of epoxy seems to increase with higher viscosity (West systems almost double)
    Sounds ike you have a cheap sypply of Polysturene and are trying to think of some way to make it into a boat.
    Whats the plan?
     
  3. tinhorn
    Joined: Jan 2008
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    tinhorn Senior Member

    Y'see, epoxy is a high-performance resin, but chopped strand mat is a low-performance reinforcement. It would be like putting high-octane gasoline in my 30-year-old beater pickup.
     
  4. kitto
    Joined: Nov 2005
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    kitto Junior Member

    Yeah I hear ya, the thing is, I have a project on at the moment coating a awkward Polostyrene shape, so using Polyester isnt possible and Choppy will give me a finish with no laps like boat cloth will.

    Any one know anything about this Styrene free Polyester?

    Cheers Kit
     
  5. ClarkT
    Joined: Jun 2003
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    ClarkT Senior Member

    No such thing as Styrene free Polyester. Maybe some chemist out there will prove me wrong.

    As for the epoxy and CSM, beware of the binders in your CSM. They are usually not epoxy compatible and while it may get the job done, don't count on it for much.
     
  6. rwatson
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    rwatson Senior Member

    The "off the shoulder" thought would be to use lots of layers if fibreglass cloth, cut into strips, oblongs or whatever it took to wrap it around the contours. You would eventually get the thickness you need, and the wetout you need because you are doing it in thin layers at a time.
     
  7. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    It's not necessary nor wise to use regular mat in epoxy laminates. Epoxy's much higher elongation and modulus, plus it's gap filling properties mean a cloth only layup is generally desired. This takes advantage of the physical properties of epoxy, particularly if vacuum bagged, producing quite light, very strong and thinner laminates. The use of mat is a waste of epoxy in most cases, though an epoxy compatible mat or a core bond putty can be used in difficult to bond situations.
     
  8. susho
    Joined: Dec 2006
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    susho Composite builder

    wasn't CSM hold togheter by a sort of styrene, wich desolves when the polyester is applied? If so, it would be weird to apply on the product when epoxy is used :p
     
  9. Herman
    Joined: Oct 2004
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    Herman Senior Member

    Gee Susho, I seem to bump into you every time...

    CSM is held together with either an emulsion or powder based binder. The emulsion binders are stronger, so the mat is more difficult to tear in the right shape, but the powder version creates some dust, which is not desirable. Price is usually no difference.

    These binders are soluble in styrene, the component which can be found in about any polyester or vinylester resin. Once the resin is on, the mat is easy to work around corners, de-air, etc.

    With epoxy, the binder will not dissolve, and the mat will be a pig to work with. Use some woven roving or a woven glass of some sort. About any will do.

    There are CSM's which are compatible with epoxy, however. They are held together by stitching it. Much in the same way a ncf (non crimp fabric) is held together. We buy these at Selcom. Other ncf producers might have the same material.

    About polyester on polystyrene:
    I am preparing a press release now, as we have the material to do it. It is a polyester based material, which will not attack styrene, but will bond to it efficiently. Really nice material for a lot of industries. However, we are in Europe...
     
  10. kitto
    Joined: Nov 2005
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    kitto Junior Member

    Hi there,

    I am currently working in the South of England at the moment for a company called Cordek. The department I manage runs 3x 5 axis routers our largest has a cutting envelope of 13mtr x 5mtr x 2.5mtr. We use epoxy at the moment because of how Polyester reacts with Polystyrene.

    I would be very interested to find out more about what yoy are releasing.

    Cheers Kit
     
  11. susho
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    susho Composite builder

    Yes, I use composites and you sell them, weird huh :p
    And on forums like this and modelbouwforum you can learn a lot about them, so I'm here to learn from people like you, So I think this isn't the last time we bump into each other ;)
     
  12. Herman
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    Herman Senior Member

    @ Kitto:

    I will Email you some info soon.

    @ Susho:

    Still sanding at Schaap Shipcare?

    Forums are great for info. However, always be careful. Ideas are always great, but nothing substitutes some decent testing.
     
  13. susho
    Joined: Dec 2006
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    susho Composite builder

    yes, mostly shipcare, somtimes composite, both need people, so I'm always more than welcome at both, but usually shipcare wins :p
    Now it is mostly clean the policeboats, no fairing and sanding last month :D
    I still have my own boat(waarschip 570) and my scale models, where I can do whatever I want with composites. what I see at schaap, I try myself.
     

  14. Roly
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    Roly Senior Member

    When it is said that epoxy is a high performance resin it should be qualified by
    "higher" rather than high. IMO.
    UTS, Mod, % elongation to failure.
    isophalic poly- 71Mpa, 3.9, 2
    West Epoxy- 50-76 Mpa, 3.66, 5-6 (Hardener depend)
    Then epoxy has other qualities, such as adhesion and water resistance.

    Then there the expensive epoxies.
    Can't see the point in using CSM with epoxy when you can use DB.
     
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