Plastics

Discussion in 'Materials' started by Jetskiobsession, Jul 16, 2018.

  1. Jetskiobsession
    Joined: Jul 2018
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    Location: New York

    Jetskiobsession New Member

    Hello,
    This is my first post in this forum so thanks for providing it! My question is about making large scale plastic molds. I love what sea-doo has done with the spark for whoever is familiar and i am curious as to how it was done? Is this injection molded or Roto-molded? Also, is this a viable option for 1 offs? Very interested in hearing back, also, looking for any additional information that you may have!
     
  2. JamesG123
    Joined: Mar 2015
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    Location: Columbus, GA

    JamesG123 Senior Member

    Both injection and roto molding require significant investments in machinery and tooling. Its not viable for 1 off or home gamers.

    Oh and welcome to the forum.
     
  3. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    The hull is called "polytec" which sounds like a brand, rather than a type of plastic. Certainly there is no scope for backyarders to mould with thermoplastics, assuming that is what it is. But virtually any shape can be achieved with GRP, by enthusiasts,with the right moulds, and/ or methods.
     
  4. Jetskiobsession
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    Jetskiobsession New Member

    Do you know what method of production is used on the polytec plastic?
     
  5. JamesG123
    Joined: Mar 2015
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    JamesG123 Senior Member

    "Polytec" is just Sea-Doo's marketing dept gimick for some flavor of fiber reinforced plastic. They have since moved on to a new one; "CM-Tech".
    Web searching either term will provide the info you seek.

    No, you can't do it yourself. But what you could/can do is take a mold of the jet-ski or whatever, part, and create your own copies of it in hand laid up fiberglass. They probably won't have the strength to weight ratio, and you'll have to figure a way of all the mounting bosses and screw lugs that are cast into the OEM moldings, and you surely can't punch them out by the hundreds per hour like Sea-Doo does, but... there you go.
     
  6. Mr Efficiency
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    Mr Efficiency Senior Member

    I assume it is a thermoplastic, polyethylene perhaps, they do claim it has the advantage of being a uniform colour, and scratches and scrapes don't show up like gel coat scratches in GRP. But I can't see anything on the net to say exactly what it is.
     
  7. SamSam
    Joined: Feb 2005
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    SamSam Senior Member

    From what I can tell it's a secretive combination of the above and the molding procedure is vacuum infusion. That kind of molding process (infusion) is backyard do-able. I think even thermo- vacuum forming is a backyard possibility. Here's a pdf about vacuum forming...

    https://capla.arizona.edu/forms/shop/fromechvacuumguide.pdf

    .
     
  8. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    If you look at the mold marks, all PWC I know of are made in a male/female mold set.
     

  9. SamSam
    Joined: Feb 2005
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    SamSam Senior Member

    I think you're right because it would be impractical to make such complicated shapes on a mass scale using infusion. It looks like the deck and hulls are not even made the same and are of different materials and/or processes also. But there is so little information and it's so vague and secretive, who knows? Is CM Tech and Polytec two different materials or is CM Tech a company that make a product called Polytec?

    OP, I doubt the process is simple or cheap and then there did seem to be a lot of complaints of cracks in the hulls, glass and resin patching and plastic welding were the two repair methods.

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    "Sea-Doo uprooted its conventional deck molding process for a new process of laying multi-layer thermoformed sheets of Acrylic and ABS into the mold before the fiberglass is injected. This results in a high gloss acrylic finish on the top deck that is more resistant to chipping and cracking due to the flexible nature of the acrylic sheets (as well as a smooth inner surface). This new, flexible CM-Tech material will be ideal when all medium and full-sized runabout hulls are eventually replaced with Polytec."

    .
     
    Last edited: Jul 22, 2018
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