FSP "fiber spray putty" to build boats

Discussion in 'Materials' started by pacoblasco, Nov 28, 2006.

  1. pacoblasco
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    pacoblasco Naval Architect

    Do anybody works with fiber spray putty?
    I use to work with monolitic GRP or PVC-cored GRP, but recently I heard that you can use fiber spray putty to use like a core but using less man hours.
    Do you have experience with Euromere FSP (http://www.euromere.com/gb/euromere.htm#fiber spray putty) or similar process?
    What do you think about this?

    Regards
     
  2. Herman
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    Herman Senior Member

    We use ITW Spraycore material here, without any problems. Just get the right spray tips for the material. The people of Spraycore can help you with that. (www.itwspraycore.com)
     
  3. marshmat
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    marshmat Senior Member

    Can you use it for a boat? Yes.
    Should you? I would have to say NO! NO! NO! BAD IDEA!
    Why? Well, David Pascoe explains it better than I can.... http://www.yachtsurvey.com/Fiberglass_Boats.htm
    The stuff you mention, and similar materials from their competitors, is renowned in the boating industry for being complete garbage. It's not nearly as strong as claimed once it gets wet, it doesn't fatigue well, etc, etc. If your goal is to build cheap crap, go ahead. If you value quality and durability in your products, I would steer clear.
     
  4. Herman
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    Herman Senior Member

    You're not supposed to use it everywhere.

    Here it is used in difficult to core boats (overlapped clinker built) which have CE cat. D classification, a 4 hp engine and see hardly any battering at all.

    It is also used in bench lids and similar things, as well as a wide range of industrial products. (out of scope here)

    However, I can imagine why boatbuilders tend to use it anywhere. Even in high-load boat hulls like the ones in the link shown.

    Firstly, it works cheap. As prices for consumer products are under heavy pressure, and competition is high, you always look for cheaper ways of production. Spray putty helps in that sense.

    Second, there are plenty of rules for fiberglass boats in terms of tensile strength (mostly not a problem, even at marginal amounts of glass) and stiffness. (usually the limiting factor, so most boat laminates are calculated to reach a certain amount of stiffness.). However, impact strength is mentioned knowhere, and I do believe that there is definately a need for at least some guidelines of what a laminate of a certain boat type should be able to withstand.

    However, that does not mean spray putty is a bad products. It has its advantages, but also its limitations. Always use the advantages in the best way, and steer away from its limitations.
     
  5. marshmat
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    marshmat Senior Member

    Good points Herman. My point wasn't that the stuff itself is evil- it's not- but rather that it is not a good boat material. It's great for benches and seats, for instance. I use a very similar foam material (albeit epoxy-based) in many of the moulds I deal with. But I have yet to come across a spray or putty core that has the water resistance, the fatigue resistance or the shear strength that are needed for even a small, lightly loaded boat. These are useful industrial products that many boatbuilders repeatedly misuse, and generally do a crappy job of misusing at that.
    With the current trend towards 'full disclosure' (Doral, for instance, lists the actual laminate schedules for each model right on their marketing website), do you really want to be telling your customers "it's made of gelcoat, 2 layers CSM, half an inch of spray putty, then 1 layer roving"?
    If you use this stuff in places it's not meant to be used (ie. boat hulls), there is a very good chance that you will pay out far more in warranty costs than you would pay to do it right the first time. I can testify that these putties take a LOT more skill to use properly than might be expected.
     
  6. pacoblasco
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    pacoblasco Naval Architect

    Thank you.
    I know it can be used in general applications, and I see in the brochures (also in the web) they are using it to build boat hulls.
    If we can do we can save some time, but I am not sure.
    Maybe I should contact the manufacturer to know if the material fulfill the ISO or classification society rules for hulls.
    Somebody told me they are using it in Beneteau boatbuilder (France), and this makes me think that it is approved, at least, for CE boats.
     
  7. marshmat
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    marshmat Senior Member

    Dangerous premises to go on, pacoblasco.
    There are several common errors you should be aware of when it comes to new materials:
    (a) Trusting the manufacturer's claims
    (b) Believing in "if it's not banned by the classification society, it's OK"
    (c) Not doing a full engineering analysis on it
    Do you know its shear modulus? How about compressive strength? Shear strength after 5,000,000 cycles? Porosity? Strength after immersion in water?
    If you don't know actual, tested numbers for parameters like that.... then it's worth its weight in garbage.
    Any time a new material is introduced, you MUST DO A FULL ENGINEERING ANALYSIS!
    Imagine getting sued by the family of someone who died because their boat broke up. The lawyer asks about the engineering analysis on the hull. You say 'well, the supplier said it would work'. Guess what comes next.
    Bottom line: Do the lab tests, do the durability tests, do the engineering analysis. Then, and only then, are you in a position to make the decision.
     
  8. Herman
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    Herman Senior Member

    I do not know exactly what or how Beneteau is using spray putty, but there is a fair chance that they use a barriercoat. (ITW Spraycore 3500 for example).

    This material is sprayed in a thin layer behind the gelcoat, and greatly improves osmosis resistance and print through. In that scenario, it is NOT a structural material, and a full strength laminate needs to be behind it.

    I professionally test laminates for osmosis, and I must say that ITW Spraycore does a vey good job. Also print through is greatly reduced. On METS 2006 we had a panel on show with a glass-like finish, even after postcuring at 80 degrees C.
     
  9. marshmat
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    marshmat Senior Member

    Herman, there appear to be two different materials being discussed here.... the ITW stuff you describe in post # 8, and the Euromere FSP material mentioned in the first post. The barrier coats you describe can indeed be very valuable; improving osmosis resistance can be a valuable tool in extending the life of a hull. The Euromere FSP stuff, though, is described on their website as taking the place of a core, being sprayed up to an inch thick. This is what I have been referring to as a Very Bad Idea.
     
  10. Man Overboard
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    Man Overboard Tom Fugate

    I checked out the ITW Spraycore website. They claim to have a rot resistant product that can be used as a barrier coat. Has anybody used this product for that application? If so how well does it flow out? For instance do you still have to apply fairing compound before final gelcoat? Do you think it would be a suitable product to use over strip plank method to reduce print through of strips that sometimes occurs over time?

    Claims from website:
    Superior and cost effective wood (plywood and balsa wood) replacement, with excellet screw holding capabilities. SprayCore Wood Replacement will never rot.
    SprayCore 4000 was recognized for excellence by the National Marine Manufacturers Association (NMMA) winning an innovation award for its multi-functional features.
     

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  11. Herman
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    Herman Senior Member

    We have only experience in female molds (yet). When spray applied, the surface is smooth.
     
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