Infusing flax

Discussion in 'Fiberglass and Composite Boat Building' started by rob denney, Jun 19, 2020.

  1. rxcomposite
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    rxcomposite Senior Member

    Relatively, yes. A good electrical conductor is a good thermal conductor. If Glass is 1.0, wood is 0.12, Copper is 100. Relatively that places wood and glass in the insulator category.
     
  2. ondarvr
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    ondarvr Senior Member

    The difference between the thermal conductivity of wood and glass have a huge effect in composites.

    A wood mold is a thermal insulator, a glass mold is considered a heat sink. (Glass, as in sheets used for flat-stock and counter tops.)

    Glass cookware works well. Not so much for wood.
     
    Last edited: Jun 28, 2020
  3. ondarvr
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    ondarvr Senior Member

    That's almost a 10 fold difference conductivity.
     
  4. ondarvr
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    ondarvr Senior Member

    Just talked to a friend that was on the North Amercan Corrosion Council about 10 or more years ago when Canada was dumping money into alternet uses for flax fiber.

    Canada has a huge flax crop and was looking at markets for the fiber in composites.

    He recalled 75 million as the budget to promote it.

    The study showed that about 20% of the glass in a laminate could be replaced with flax and still retain similar strength, or at least enough strength.

    I had a customer at the time that was building several large flax fiber promotional products for an upcoming show/event for this.

    What also came out in the study was that the commercial flax crop had been bred for specific growing characteristics which significantly reduced it ability to be used in composites.

    Natural flax, or at least more natural than what was being grown in Canada, tested much better as a fiber in composites.

    The money was allocated and spent, the products were built and paid for, then it all went nowhere.

    This is the typical result from an effort to introduce natural fibers.

    I'm not against natural fibers, it would be great to have low cost, greener option for building items that don't require the properties of glass.

    The problem is that glass is cheap, and the infrastructure is in place to supply it just about everywhere on the planet at anytime in any quantity.


    Also the engineering is well understood using the current very consistent physical properties of the typical fibers.

    The industry has been based on using glass for so long that it will be difficult to convert to something else with a higher cost and lower physical properties that may be inconsistent.
     
  5. rxcomposite
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    rxcomposite Senior Member

    That seems to be a personal conclusion and anecdotal at best. I subscribe to a lot of composite magazines and research but it is not viewed that way.
     
  6. ondarvr
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    ondarvr Senior Member

    Research as to what a fiber may be capable of is different than what goes on at the shop level in choosing a fiber.

    Fabricators take the path of least resistance, which for now is typically glass. There's some carbon and Kevlar mixed in, but its a small fraction of the glass.

    I work with these shops in choosing products and methods to meet their objectives. Normally it's building a good part for the least amount of hassle and money.

    Occasionally the goal is to use a different fiber for a specific reason. I don't know of any that stayed with the alternative fiber when the orignal need had been met.
     
  7. Rumars
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    Rumars Senior Member

    The biggest industrial user of natural fibers as reinforcement for composites is the automotive industry. It is used with thermoplastics to make interior paneling. The problems they identified are:
    1. Limited availability. Basicly they can not get enough hemp and flax and have to also use lower quality substitutes like jute and others.
    2. Price. The more refined the fiber the higher the price. To make high quality yarns you need the longest fibers with the most consistent diameter possible, spun on very good machines. That's why they use only coarse fibers in very open weaves or as unwoven material (sort of like CSM).

    High quality flax or hemp is very expensive, it has to do with how it is processed. Carbon fiber is cheap compared to it.
     
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  8. rxcomposite
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    rxcomposite Senior Member

    Yes, I agree. Most of car interiors are made of natural fibers. Natural fibers like basalt has a niche in the industry. It is used where it is good at.

    It will take time before the manufacturers/growers, processors, and weavers shake their hands together to make a cost effective mainstream product.
     

  9. Rumars
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    Rumars Senior Member

    Well, just to show it is possible, there actually are boats made out of natural fibres. Marc Van Peteghem was involved with at least two, Tara Tari (2009), 60% glass, 40% jute, with polyester resin, the second one, Gold of Bengal (2013), 100% jute, polyester resin (infused). Both boats made successfull journeys, but full scale production in 100% jute still awaits implementation (I suppose it's price related, chinese glass is cheaper). Anyone interested can contact the builders about their experiences, it's an NGO (explore the site, I linked directly to the 100% jute construction photos).
    Expédition Gold of Bengal - Gold of Bengal http://goldofbengal.com/expedition/expedition-gold-of-bengal/
    The Tara Tari story is also on the above site, then the boat got to live on under new ownership Interesting Sailboats: THE MOST BEAUTIFUL SEA STORY? http://interestingsailboats.blogspot.com/2014/04/the-most-beautiful-sea-story.html
     
    Chris Rogers and Dejay like this.
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