Infuse two sides foam at once

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

  1. ondarvr
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    ondarvr Senior Member

    On that size panel, and since you are sanding and painting anyway, I’d only do one perfect side. Infuse it on a glass table with peel-ply on the top. The time spent trying to get both sides perfect, only to sand and paint them would take longer and be more complicated than sanding and fairing a peel-ply surface.
     
  2. MassimilianoPorta
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    MassimilianoPorta Junior Member

  3. MassimilianoPorta
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    MassimilianoPorta Junior Member

    This is a sketch of what I want to produce:

    ttop_1.jpg

    ttop_2.jpg

    The borders are exaggerated, I would like them just 3-4 mm thick.

    My idea would be to shape an xps foam for the base and lay a plexiglass so that at least the bottom will be smooth.
    Will it work if I apply another plexiglass sheet on the top?

    The schedule will be then, from bottom to top:
    plexyglass
    release film
    fiberglass
    Pvc foam with holes
    fiberglass
    peel ply
    flow media
    Plexyglass sheet
    Breather (not to punch the bag)
    Bag

    Inlet on the short sides, one single outlet in the middle.
     
  4. rob denney
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    rob denney Senior Member

    Inlet on the long sides. And maybe wrap it round the corners a little as well. And make sure you have a catch pot in the vac line. I would feed from one long side across to the other, have the vac line 100mms from the edge with strips of peel ply connecting it. Make sure the plexiglass is the same size (or smaller) as the laminate, otherwise the edges will bend or the bag break. Make sure the bag is tight in the corner between plexigalss and table. A 300 x 300 test piece will tell you a lot.
     
  5. rxcomposite
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    rxcomposite Senior Member

    Plexiglass is acrylic. Poly will dissolve the plastic. Not sure about the epoxy resin.
     
  6. MassimilianoPorta
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    MassimilianoPorta Junior Member

    ttop_3.jpg

    Something like this?

    I will do some research on this
     
  7. rob denney
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    rob denney Senior Member

    Yes, but think of it as vacuum outlet, not resin. There should not be any resin in the vac line, or need for a catch pot if you do it right..
     
  8. MassimilianoPorta
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    MassimilianoPorta Junior Member

    Yes, I should have written vacuum outlet. As this will be my first infusion, a catch pot is mandatory otherwise it could become my last one :D

    How many feeding lines in the inlet do you recommend, just one in the middle or more?
    Same question for the outlet, thank you :)
     
  9. Eric ruttan
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    Eric ruttan Junior Member

    Burt Rutan has been making aircraft out of polystyrene and epoxy longer than most of us have been alive.
     
  10. MassimilianoPorta
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    MassimilianoPorta Junior Member

    Thank you Eric, I was meaning research if it is possible to use a plexyglass sheet as a mean to smooth the surface and skip or have less sanding and fairing.
     
  11. rxcomposite
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    rxcomposite Senior Member

    Plexiglass is acrylic. Acetone or Mekp will melt it. Polycarbonate is a similar plastic with clear bluish properties. Polycarbonate, we use as aircraft windshield. Lexan, a brand is an improved properties of polycarbonate. Also used as windshield.

    We use polyethylene or nylon sheet (can't remember which one) for our laminating board because of the self healing properties and it doesn't stick.
     
  12. MassimilianoPorta
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    MassimilianoPorta Junior Member

    I will try to source pe or nylon then, thank you!
     
  13. rxcomposite
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    rxcomposite Senior Member

    Resin Flow is always radial and the best result is the feed is at the bottom and resin is pulled by vacuum from the top edge. If you want it from left to right with two side simultaneous, You must have a resin distribution/flow pipe/spiral tube from the feed line so that both upper and lower fibers are fed at the same time. On the opposite end is a flow medium a vacuum cut off and a resin trap. The diagrams should help you figure it out.

    Just watch out for styrene outgassing if you are using poly as illustrated in the article.
     

    Attached Files:

  14. MassimilianoPorta
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    MassimilianoPorta Junior Member

    Thank you very much for the schematics rxcomposite. I am going to use epoxy both for strenght and no vapors.
    I will try to refine more my drawing for the intended placement of resin distribution pipes
     

  15. rxcomposite
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    rxcomposite Senior Member

    Always use more vacuum ports than resin feed so you can have more control over the resin front. Say 1 resin port= 2 vac lines. 2 resin port=3 vac lines. Once the resin flow has reached its destination or the resin catch can is starting to fill, close the connecting vac off.
     
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