Inexpensive hull construction materials

Discussion in 'Boat Design' started by fpjeepy05, Dec 9, 2019.

  1. ondarvr
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    ondarvr Senior Member

    Yes, the correct formula can achieve a good bond, the cost will probably be higher for this type of resin.

    Grinding the ABS into a powder may cause it to dissolve completely in the resin
     
    Last edited: Dec 20, 2019
  2. rxcomposite
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    rxcomposite Senior Member

    According to my reference book, ABS plastic is commonly mixed with rubber. Although the product is already polymerized, it has poor resistance to solvents.

    These are the specific chemicals that attack ABS- "ABS polymers are resistant to aqueous acids, alkalis, concentrated hydrochloric and phosphoric acids, alcohols and animal, vegetable and mineral oils, but they are swollen by glacial acetic acid, carbon tetrachloride and aromatic hydrocarbons and are attacked by concentrated sulfuric and nitric acids. They are soluble in esters, ketones, and ethylene dichloride." Wiki
     
  3. fpjeepy05
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    fpjeepy05 Senior Member

    I asked, which was stronger.

    I didn't as which was harder. I didn't ask if it has good properties for a core. I didn't ask who uses it. I didn't ask how to apply it. I didn't ask about its density, I didn't ask about how well it will bond. I didn't ask how much it will cost. I didn't ask where it will be sourced.

    One material can be stronger than another and still be a worse core material.

    Discussions seek common ground. You just want to use your 50 years of negativity to argue. I'm not interested.
     
  4. fpjeepy05
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    fpjeepy05 Senior Member

    It is cheaper than PVC core.

    I was using stronger as a general term. Modulus of elasticity in compression and elongation at failure would be more accurate terms if you want to be nit-picky.
     
    Last edited: Dec 23, 2019
  5. ondarvr
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    ondarvr Senior Member

    A poly putty is typically very weak and brittle, that’s why it’s not used as a core, it’s also very expensive for what it contributes. “Hard” is about the only thing it has to offer.

    You can improve the strength by adding fibers and other products, but now the cost goes up.

    And you still haven’t explained how you are going to use this mix easily as a core.

    What you are talking about is not new territory, the idea has been around for many decades.
     
  6. fallguy
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    fallguy Senior Member

    This thread has drifted close to sealioning. Perhaps not intentionally, but the which is stronger is sort of the perfect way to sealion.

    just sayin

    Ondarvr is a class act on this forum.

    Do be kind.

    And I intentionally am quoting Ondarvr to avoid useless debate.
     
  7. ondarvr
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    ondarvr Senior Member

    These conversations tend to spiral like this. Someone makes a claim with nothing to really back it up, they just insist it will work and that it’s a great idea.

    What the industry has experienced trying to implement that idea is irrelevant, because the person making the claim knows better.

    A cheaper core that holds up in real world use has been searched for since composites first started being used.
     
  8. ondarvr
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    ondarvr Senior Member

    Let’s say you can find a filler for polyester resin that is a by product of some other manufacturing process, and it’s free. It also increases the physical properties so it becomes an excellent core.

    Now you have a paste that needs to be applied to a surface in a consistent thickness over a large area. This is where the hassles and costs start to escalate.

    You can buy equipment to extrude putty onto a surface, but for production purposes it’s very slow. This equipment can be very expensive too, with a good deal of training involved.


    The cast/cultured marble industry does something like this every day, they mix very cheap “dirt” with polyester to create a sheet material used for counter tops, showers, and other items.

    Even using very low cost materials that have poor physical properties and is extremely heavy, the cost is high due to processing.
     
    Last edited: Dec 23, 2019
  9. rxcomposite
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    rxcomposite Senior Member

    No general term here. Use the correct term if you pretend to know what you are talking about. "Modulus of elasticity in compression and elongation at failure" is nowhere to be used to be used when defining core property for use. Quit pulling our leg.
     
  10. gonzo
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    gonzo Senior Member

    If the core fails by elongation, either it is more brittle than glass, or the laminates are made of rubber.
     
  11. Rumars
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    Rumars Senior Member

    In the end it's all pretty simple even if the OP does not want to see it. A cored panel will always be thicker then the equivalent single skin one. If one uses enough filler material to strech poly resin enough to make a price difference the core will be unsuitable for the task. It's simple math, and if the OP would actually calculate or make a test panel he would also know it.

    Going back to his initial topic of stringers it's similar. Either you use a material that can take the loads by itself and wich does not need fiberglass caps for strenght, or the fiberglass cap takes all the load and the inside can be hollow.
     
  12. waikikin
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    waikikin Senior Member

    Hi fpjeepy,
    There's an observation... 8 negative words highlighted. Discussions should seek common ground but a level of respect needs be applied as often once all the information distilled the answers sought might be revealed. There's a big difference between being dictatorial and collegiate & I know who achieves the greater success and respect. Open forum, bring some, if you already have the answers you seek share them or not.

    Regards from Jeff.
     
  13. Mr Efficiency
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    Mr Efficiency Senior Member

    I don't think jeepy is overly familiar with the idea that you catch more flies with honey, than you do with vinegar ! :rolleyes:
    Nevertheless, I wish a happy Christmas to all ! :D
     
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  14. fallguy
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    fallguy Senior Member

    Merry Christmas to all!
     
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  15. ondarvr
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    ondarvr Senior Member

    All of the “I didn’ts” are how you qualify a core for use in a particular application.

    All is good, have a nice holiday everyone.
     
    Last edited: Dec 25, 2019
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