Infuse two sides foam at once

Discussion in 'Materials' started by MassimilianoPorta, Nov 14, 2019.

  1. MassimilianoPorta
    Joined: Apr 2019
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    MassimilianoPorta Junior Member

    Hi, I wonder if it is possible to infuse a PVC foam core panel on both sides at once, specifically to get two smooth surfaces, therefore not requiring any fairing and just paint.
    What could be the technique/schedule?
    Thanks!
     
  2. gonzo
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    gonzo Senior Member

    You can also infuse each side individually and get a reasonable fair surface. However, it depends on what kind of finish you consider smooth enough. To do what you ask, there will need to be a male and female mold, which is really hard and expensive, unless you mean flat panels.
     
  3. MassimilianoPorta
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    MassimilianoPorta Junior Member

    Thank you!
    I was meaning flat panels and was wondering if I can layuop on glass for the bottom and place another glass (or plexyglass) on the top to have a perfect smooth finish.
    But then, how could the resin flow? Where should I place the inlet and the outlet?
     
  4. gonzo
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    gonzo Senior Member

    Infusion is something that takes a lot of knowledge and practice to get right. Any mistakes and you will have to throw everything away. For flat panels it is much easier to vacuum bag.
     
  5. ondarvr
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    ondarvr Senior Member

    It can be done, and it’s not that difficult, but as gonzo said, it takes a bit of knowledge and practice to make “easy”.
     
  6. MassimilianoPorta
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    MassimilianoPorta Junior Member

    I will try with small panels, taking into account something can and will go wrong :)

    The test panels will be rectangular with the inlet on the short side and the outlet on the opposite short side.

    My idea of a schedule would be:
    - waxed glass (or plexiglas) with applied unwaxed gelcoat and veil
    - fiberglass
    - foam
    - fiberglass
    - waxed glass (or plexiglass) with applied unwaxed gelcoat and veil

    Of course the veil would be applied on the gelcoat once it reaches a tacky state.

    How can I ensure the resin would fill all the fiberglass? Cut grooves on both sides flat sides? Holes? Both?

    What do you think of my schedule?

    Thanks!
     
  7. KD8NPB
    Joined: Mar 2018
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    KD8NPB Junior Member

    I do it all the time via RTM light process.
     
  8. MassimilianoPorta
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    MassimilianoPorta Junior Member

    Could you give me some hints?
     
  9. ondarvr
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    ondarvr Senior Member

    Anything you do to the foam as far as grooves or holes will print onto the surface, so if cosmetics are important remember that.

    The glass chosen can provide the flow, they can be had with the flow media built in.
     
  10. MassimilianoPorta
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    MassimilianoPorta Junior Member

    You are right, did not think about that...

    You mean like Soric?
     
  11. rxcomposite
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    rxcomposite Senior Member

    We made a lot of 4' x 8' panels smooth both sides but not infusion. It is 1.flat mold, 2.peel ply, 3.prepreg. 1st layer, 4.dry film, 5.core, 6.dry film, 7. prepreg, 8.peel ply, 9.then caul plate of waxed galvanized steel. The top was covered with 10. vacuum cloth. 11. Bagging film, vacuum lines at the edges. The caul plate was drilled with 1/16" holes every 6" to even out the vacuum.

    You can try wet bagging instead of infusion. Wet the fiber with resin, squeegee it out, follow the procedure stated above (eliminate dry film), then apply vacuum. For the top layer, you can wet it out in a nylon backing sheet, invert it and position it on the foam then remove the backing sheet. You can also use perforated film as a backing sheet so you don't have to remove it but you have to experiment with the size and spacing of the perforation holes. Always use perforated caul plate else you will have a lot of local delamination the size of golf balls. I have tried this technique on small curved panel and it worked. Expect lots of bleed out/excess resin depending on vacuum setting
     
  12. MassimilianoPorta
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    MassimilianoPorta Junior Member

    Thank you rxcomposite.
    The holes on the caul plate do not leave marks on the layer below the peel ply? Or they are too small to leave a mark?
     
  13. KD8NPB
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    KD8NPB Junior Member



    Both molds can be gelcoated if desired.
     
  14. MassimilianoPorta
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    MassimilianoPorta Junior Member

    This is pretty amazing!!
     

  15. KD8NPB
    Joined: Mar 2018
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    Location: South Carolina

    KD8NPB Junior Member

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