Serial Resin Infusion Boat Hull

Discussion in 'Fiberglass and Composite Boat Building' started by KnottyBuoyz, Aug 9, 2014.

  1. KnottyBuoyz
    Joined: Jul 2006
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    Location: Iroquois, Ontario

    KnottyBuoyz Provocateur & Raconteur

    I've been scouring Youtube for resin infusion vids of boat hulls. Most mfgr's infuse the inside of a boat hull from the bottom of the keel up to the gunnels. There is one particular video showing what the mfgr calls a 'Serial Infusion'. See it here.

    http://youtu.be/_J6SGZZolbU

    It got me thinking. On a large infusion there's always a lot of risk involved, not just the money, but the requirement for a consistent fully infused part. If i infuse the inside of my boat hull, 31-1/2' long by 10' wide I'll have to cover just over 600 sq ft in one pull. By dividing up the pull into smaller segments I can better control the results I think.

    I put together a crude animation to illustrate what I'm thinking about. I do apologize it's not Pixar quality!

    http://youtu.be/N4HN8A16WzI

    All feed lines, spiral wrap etc. will be 1/2". I may not actually use valves but just kink the feed & vacuum lines as required.

    Thoughts, comments, suggestions? Always glad to have some feedback from anyone.
     
  2. kapnD
    Joined: Jan 2003
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    Location: hawaii, usa

    kapnD Senior Member

    Aren't you increasing the complexity of the process? The resin flow needs to be continuous throughout the infusion process, seamless, so to speak. Your aft to fore "zone approach" may take a lot of time to accomplish, and leave joints in the resin, especially when it flows where you don't want it to go, as it will along the keel, chine and transom corners. How will it pull up the sides to the gunnels? Gravity needs to play its part in the process.
    I would stick with the tried and true approach to reduce risk.
     
  3. KnottyBuoyz
    Joined: Jul 2006
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    KnottyBuoyz Provocateur & Raconteur

    I know it was an oversimplification trying to illustrate it. The feed/vacuum lines would stretch all the way across the hull hugging the inner surface. Under a full vacuum gravity has absolutely no affect on the pull (most are done bottom to top) which is towards the vacuum. The next feed/vacuum line is about 30" away. Once the resin front hits the second feed/vacuum line the following valves are closed and the next set open. There's a full vacuum maintained on the entire bag from the last vacuum inlet at the bow.

    I think it's much more simple than some of the hull infusions I've seen on Youtube where there's tens of feed lines & tens of vacuum channels laid in the hull. They're usually opened in sequence which requires a half dozen guys on hand to coordinate it. Just like in the example video one person can easily handle one hull. In my case two sets of hands would likely do it.

    I'm trying to avoid this!

    [​IMG]

    This looks a lot simpler to me!

    [​IMG]

    The complexity of the vacuum manifold (for lack of a better term) is no more complicated than 10 or 11 T's spliced into a line. The resin feed lines are individual so they can be as short as possible (reducing waste). I think doing it this way also simplifies the bag. No punching holes in it for vacuum ports & feed lines. Everything is done from the gunnels. Once you get the layup done and the bag on and pull it down there's a lot less chance you'll have to go inside to find a leak.

    I don't expect this to be an approach that'll speed up the process. At just over 600 sq ft that's a lot of resin to move through a layup. I will do a test this winter. I suspect that it'll infuse at about 2 inches per minute. Each zone being 30" will take approx. 15 mins. Total time to infuse the whole hull approx. 2 hrs 45 mins or less. If I wanted to go faster I could actually start in the middle and work my way outwards! ;)

    Thanks for chiming in. I do appreciate it and that's what we're here for right? To talk it through?
     
  4. groper
    Joined: Jun 2011
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    Location: australia

    groper Senior Member

    One problem is race tracking. When your boat has chines and places with abrupt changes in direction, the resin often races down those areas faster than the rest of the laminate. The problem with your strategy, is that should this occur, you have a big problem towards the end of the infusion and a dry spot encircled with resin at the bottom of the hull near the bow.

    I would run a series of lines, starting at the keel and working upwards. Same process, you only have 2 lines open at one time. 1 pair would run at any chines. The rest seperated at appropriate intervals depending on your resin viscosity and flow media.

    The vacuum lines don't need all those valves, they can stay open provided you have a decent resin brake zone at the edges. Stop the flow media 2 inches short of the brake zone also.

    Some of the infusion strategies you see on YouTube are rediculous. Probably set up by infusion consumables sales reps. Maximum use of consumables so the client spends more money per job...
     
  5. KnottyBuoyz
    Joined: Jul 2006
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    KnottyBuoyz Provocateur & Raconteur

    I was trying to model the hull in Sketchup but my drafting skills aren't up to it. Here's a view of one that was built & hand laminated in Belgium.

    [​IMG]

    You can see the deep box keel. The only difference is mine is 1 meter longer. That would likely pose some difficult challenges to my serial infusion strategy! (we need a forehead slap icon).

    Another view, same boat from transom to bow.

    [​IMG]

    If I infused the keel separately then sealed it over I'd have one turn at the chines to the gunnels. I've thought of race tracking in these areas but never having done anything this size I have no experience with it. I did get some on a smaller part I made when the fabric bridged from the foam core to the tooling surface.

    I'll have another go at it.

    Thanks again groper. Got any pics/video of your infusion work? I would go looking if I knew where.
     
  6. groper
    Joined: Jun 2011
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    groper Senior Member

    My build thread is located here http://www.boatdesign.net/forums/bo...displacement-powercat-build-thread-38588.html

    That box keel completely blows your original idea... With yours, an elliptical resin front would work well. Started at the bottom of the keel, the second feed would be a ring around the top of the keel. Then another ring around this on the hull bottom, and so on, until you get to the outer chine. Another feed here, pulling it up to the gunnels.

    When sequentially opening the feeds, you must wait until the resin front completely passes the next feed line, BEFORE you open it, other wise you trap a dry spot just behind the next feed, where the front has not passed yet.
     
  7. KnottyBuoyz
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    KnottyBuoyz Provocateur & Raconteur

    Laying out the vacuum & supply lines something like this.

    [​IMG]

    I'm guessing that the darker material is some sort of vacuum/flow channel.
     
  8. groper
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    groper Senior Member

    Yes, exactly.

    They are using Enka channel by the looks of it. It's expensive but doesn't leave appreciable print on the finished laminate and it's easy to apply it on those vertical surfaces.
     

  9. jorgepease
    Joined: Feb 2012
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    jorgepease Senior Member

    Since I have seen resin flow with no signs of slowing to the center of an 8' panel and since I infused my 22' x 8' inwards I would be tempted to infuse this inward in three sections similarly. The verticals don't matter if you have packed your laminate well and have no bridging.

    Also always plumb an extra vacuum line with a veterinarians needle on it. Wrap the needle with the tacky tape so you can puncture the bag if you get a dry spot. Had to do this once and it worked perfectly and will have it on hand for my next infusion.
     
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