Finish surface from infusing a multi-sided part around a core

Discussion in 'Fiberglass and Composite Boat Building' started by Tarek, Sep 23, 2009.

  1. Tarek
    Joined: Sep 2009
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    Location: Clearwater, FL

    Tarek Junior Member

    Greetings everyone!

    This is my first post so please be gentle. :eek:

    I've been reading up on resin infusion, which seems to be pretty well documented here and everywhere else on the net, however I found very little on infusing 2 (or all) sides of a core simulateneously. I think it would be challenging to get a good finish surface, because that surface would have imprints from the flow media and bag, not the mold surface itself - unless someone here knows of a trick or two.

    Thank you in advance!

    Tarek
     
  2. jim lee
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    jim lee Senior Member

    Look up "lite RTM" google it.

    Positives I've seen with lite RTM is you can pump out parts like mad. Both sides look wonderful, little or no print through.

    Downside? You can't get near the strength to weight you can with open infusion.

    -jim lee
     
  3. Tarek
    Joined: Sep 2009
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    Tarek Junior Member

    Thanks Jim,

    I looked up lite RTM and it seems more suitable for thin walled double surface items, and require the construction of a second mold, similar to the case of a mechanical pressure mold. One would have to be very skilled at building the second mold, at a consistent and perfect gap from the first one. I would imagine would need calibrated wax and spend quite a bit of time perfecting the setup for the second mold. Is that what you are recommending?

    I'm not sure if that is what I'm looking for, based on the items I'm looking to infuse - please enlighten me, if I'm missing something - I'm looking to infuse items like a surfboard or RC airplane wing in one shot, around a completely enclosed foam core and get the desired clean carbon fiber surface with no prints from flow media, peelply, bag fil, etc. and without resorting to building separate halves and gluing them together in a separate process. Are you saying it's the same process for those? how?

    I aplogize in advance if my I sound misinformed

    Thanks again. I greatly appreciate the help

    TareK
     
  4. Herman
    Joined: Oct 2004
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    Herman Senior Member

    For RTM light, indeed calibrated wax is used to create a uniform laminate thickness. after that the mould edge details are added, and a thin laminate is created to act as the top mould. This is reinforced by adding more glass, some core, and a steel frame around the perimeter.

    A bit labour intense, but targeted at higher output (up to 8 products per shift from a single mould) and larger series.

    About your question: Yes, it is possible, but the core should act as a resin transfer medium. (have small cuts).

    Soric (www.lantor.nl) is also a possibility. Wrap your core in Soric, then the fabrics, then infuse.
     
  5. Tarek
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    Tarek Junior Member

    Thanks Herman,

    So I guess if I use a foam core and score the surface with a knife in a grid pattern, lay the laminate and have only the bagging film as the top layer, it should - theoretically - work?

    Regards,

    Tarek
     
  6. Tarek
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    Tarek Junior Member

    That made me realize there would be at least one (may be two) minor defect(s) in the part, at the resin inlet to be patched later? This also may be the case of the vacuum port?
     
  7. Tarek
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    Tarek Junior Member

    I'm sorry if this was discussed before. Does anyone know where I can buy Soric in the US in small quantities?

    thanks!
    Tarek
     

  8. Herman
    Joined: Oct 2004
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    Herman Senior Member

    Reply to your posts:

    -yes, you are correct
    -yes, you are correct
    -no, I have no idea. I am from the old world...
     
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