woven fiberglass fabric how much?

Discussion in 'Sailboats' started by metin_mehel, Aug 25, 2011.

  1. metin_mehel
    Joined: Jul 2009
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    metin_mehel mech.eng.

    Hello guys,
    I have designed a small catamaran LOA 5.8m and beam is 2.8m. the construction technique is stitch and glue. I just cover the inside of chines by fiberglass tapes. Nothing on exteriour.
    I will coat the exteriour with just epoxy but I am not sure that I should cover with woven fiberglass fabric. The hull is made by 8mm. thick okume marin pw.
    How about the cost of woven fiberglass fabric? Do you ofer me cheap market?
    Thanks a lot.
    Metin :confused:
     
  2. Ilan Voyager
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    Ilan Voyager Senior Member

    8mm plywood is too much but can work. On this size a 6mm is generally enough. That depends of the use of the boat.
    I counsel you to cover outside (and decks) with a 160-200 gr/m2 satin fiberglass to control the thickness of the epoxy (are you using epoxy?). That will last far longer as that gives a harder surface.
    If the cata is often beached a second layer on the keel zone is good practice.
    I have no idea of the prices of fabric in Turkey.
     
  3. metin_mehel
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    metin_mehel mech.eng.

    Ilan,
    I applied westsystem epoxy filled through chines inside. But only one layer of fiber tape was laid on each fillet. Moreover the beam of one hull is 50cm and 580cm in length but there are only 3 bulkheads (8mm okume). There are no stringers. So I am thinking the design is little bit weak. I asked to Dudley Dix if he coat exteriour of his boats. About Didi 26 he said he only reinforces some places and he does not cover exteriour with fiber. In turkey 200gr/m2 fabric is about 7.2$ do you think it is expensive? Can you compare it in your country?
    Thanks
     

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  4. Ilan Voyager
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    Ilan Voyager Senior Member

    Metin-Mehen. A 580*50cm hull is largely enough with a 8mm okoume. I do not see the need for stringers.

    It's simpler when building to give the extra strength of the surface with a few meters of fiberglass cloth so the paint will last years.
    The keel is particularly exposed and a few extra layers made with all the chutes is a good feature. Only the fiber is abraded and fixing it becomes very easy.
    Also exterior fiber makes the boat very watertight with no checking or cracking of the joints. Fiberglassing pays by itself at the second year...
     
  5. Ilan Voyager
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    Ilan Voyager Senior Member

    At 7.2 US $ the meter (what width?) the price is fairly good. Look at www.raka.com for the prices in the States, it's not so far. In Mexico count for about 12 USD the lineal meter in 50 inches wide for a 4 oz of last quality...

    Fiberglassing adds durability at the outer coat, as it improves stability, hardness and resistance to abrasion. It's important for a beach boat which is handled from and to the trailer, is dragged on the beach, receives a lot of knocks.

    After one season without fiberglassing you'll have to fix all dings and scratches as okoume is very soft. The boat will look miserable and you'll spend money and a lot of time. That will cost far more than the initial fiberglassing.

    That improves also the durability of the boat.
     
  6. KnottyBuoyz
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    KnottyBuoyz Provocateur & Raconteur

    Hello Metin

    I know a fellow countryman of yours who's built boats in Turkey. He may be able to help. He's asked that you contact him through Facebook http://www.facebook.com/cumhurguvenc or his cell phone 05326165886

    Regards

    Rick
     
  7. Steve W
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    Steve W Senior Member

    While i used to come down in the always glass it camp and i personally always do although my preference is for Dynel cloth i did major repairs on a very nicely built 25ft Searunner tri a couple of years ago that had only been epoxy coated apart from the chines and deck edge and at 28 yrs old with the original paint was holding up very well indeed, it had zero rot and only a small amount of checking ( it was built of 3 ply fir) which probably would not be present with almost any other plywood choice. The checking was almost all on the inside faces of the amas as it had spent winters on a trailer with the amas folded. So, while im sure i will continue to sheath, i am less convinced that it is essential. I agree with Ilan that 8mm is a bit too heavy for this size cat and since its too late to change i would probably just sheath the bottoms with a couple of layers of the fabric of your choice, my default choice is dynel, others prefer polypropylene, others glass, they all work, just some better than others for abrasion which is the main reason for doing the bottom on a boat that will be beached often. You will of course also glass tape all end grain ply such as deck edges and transom edges
    Steve.
     
  8. m3mm0s rib
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    m3mm0s rib Senior Member

    Metin, I feel that launched crooked on the epoxy will not work as polyester and will have to clean the surface to be able to do anything that prices differ from country to country but if thou look here http://www.fibermaxcomposites.com/shop /
     
  9. metin_mehel
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    metin_mehel mech.eng.

    Thank you very much for all your replies. I decided that I will only cover the wet surfaces from the closest chine. Here 1 m2 fabric with is 7$. I think at this weekend or next I can start painting. So can you advice me painting? What is the cheapest way?
     
  10. metin_mehel
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    metin_mehel mech.eng.

    some photos...

    I am realy not sure that fillets can work :) . I will live and you will watch from tv...
     

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  11. Ilan Voyager
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    Ilan Voyager Senior Member

    On beach boats, acrylic car paints work pretty well.
    Easy to use, dries very fast (3 coats in the day) so no dust, insects and hairs embedded in the paint. Dries perfectly on epoxy.
    Far less expensive than the so called marine paints and no comparison with the alkyds which often have difficulties to dry properly on epoxies.
     
  12. peterchech
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    peterchech Senior Member

    Cheapest way? Latex porch and floor paint. Down side is you may have to give a touch-up coat every year if you use the boat a lot.
     
  13. Ilan Voyager
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    Ilan Voyager Senior Member

    Surely in the States (but it looks awful with brush strokes). Not so sure in Turkey where this kind of paint is probably not common (building style is very different from the States, specially the north east)...
    Car acrylic paint is found everywhere, covers well, very easy to use with a good finish and good gloss. It lasts five years without any work nor touch up on a polyester panga in Mexico under a UV 12 sunlight and 3000 hours/year of sun with 85-100 degres F... It's my winner since 15 years.
     
  14. metin_mehel
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    metin_mehel mech.eng.

    I bought acrylic car paint and its primer (Hope works with epoxy well). NowI will buy compressor. what about jelcoat? It is cheap. Why dont we use it?
     

  15. Ilan Voyager
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    Ilan Voyager Senior Member

    Not need to buy a compressor for just a paint job. Surely someone can rent you one. Compressor for painting are small and very common, and it's a 2 days job if you prepare well before.

    Ordinary gelcoat is more destined for mold work. It doesn't work on epoxy, simply because the epoxy inhibits the hardening of the polyester gelcoat, and that becomes an ugly mess.

    Acrylic car paint works very well on epoxy. Do not worry. Prepare the epoxy surface with a last 320 sanding with water and soap. Rinse well with clear water. Let dry.

    Do not use any solvent for wiping the epoxy surface, it's the best way to have problems. If needed use only the paint's solvent.
    Spray the primer to get a good "one color" surface (generally pale grey or white-cream) and after, spray the paint as recommended. That goes very fast as the acrylic dries in minutes.
     
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