Kevlar / Vacuum Infusion

Discussion in 'Boat Yard Basics' started by CurtisWright, Sep 25, 2013.

  1. CurtisWright

    CurtisWright Light, Strong, Cheap. Pick Two.

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    Hey guys, I am about to start another build and really want to learn how to work with kevlar and do Vacuum Infusion. Is there anyone out there that knows how and wants some free labor in their shop? I have a few vacation days I can take to learn.
     
  2. 8loco

    8loco Well-Known Member

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    A new one already?
     

  3. cutrunner

    cutrunner Cert. Yamaha technician

    Lol
     
  4. DuckNut

    DuckNut Brandon, FL

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    He's just trying to keep up with Mattyvac
     
  5. CurtisWright

    CurtisWright Light, Strong, Cheap. Pick Two.

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    You have know idea what people like matty and I go through. This isnt a choice, its something were born with. Its a sick obsession with no known cures. :'(

    I want to try and build an SUP or ambush/solo like boat.
     
  6. Gramps

    Gramps Living & Dying in 3/4 Time

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    I'm starting to feel the same way... Already drafting up plans for my own Ambush type rig...
     
  7. DuckNut

    DuckNut Brandon, FL

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    CW- I am the complete opposite from you. The boat I use most is one I built in 1985. A couple updates over the years and still going. In fact, the only update was to remove the wood that was used and went with various foams to replace the wood - the layout is exactly the same.

    If you hang in there a couple more years they will probably have a pill for the obsession.
     
  8. CurtisWright

    CurtisWright Light, Strong, Cheap. Pick Two.

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    That's cool duck. I'm sure I will keep mine for a while. I think deep down, I enjoy the challenge of design and building more than I enjoy actually fishing.
     
  9. firecat1981

    firecat1981 BBA Counselor

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    I honestly don't know too much about building with kevlar, mostly because it's so cost prohibitive, but I do know it's usually mixed with other mediums. From what I've been told by another builder carbon fiber is super strong, but lacks impact resistance and can be brittle. Kevlar is very impact resistant, but can lack rigidity. So when laying up hulls many times they will use the carbon/kevlar woven cloth (looks like black and yellow checkerboard). That's all I got on that one.
     
  10. CurtisWright

    CurtisWright Light, Strong, Cheap. Pick Two.

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    Yea,  I am a Mechanical Engineer and am fairly familiar with the material property's.  Yield Strenghts,  Modulous of Elasticity's and Regidity's and so on   I am also pretty familiar with the properties of the various resins.   I think I have a fairly methodical approach to calculating impact force from a wave and using that force to detirmine the what cross sectional moment my hull needs to have. 

    Coored composites usually fail in shear at the core to laminate transition on the compression side.

    I just have no experience with infusion and materials are a little to expensive for the trial and error method.
     
  11. Dillusion

    Dillusion devilray snob

    Boats, jeeps, golf, guns...can't keep any of em
     
  12. el9surf

    el9surf Well-Known Member

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    Cwright go and visit swaylocks.com. although geared towards surfboard construction there is a ton of info on how to vac bag with different lam schedules.
    Kevlar itself doesn't have the structural integrity you need. You would need a blend. Also kevlar can present a cutting and major sanding issue during construction.

    I have built a couple surfboards from scratch with great results. I can tell you that resin research epoxy is far superior to a standard poly resin. Its impact resistance is truly impressive. Where a standard poly lam schedule would crack and shatter on a decent impact the resin research cured product won't show near as much damage.
    Also if you want to build an sup you can source a blank from us blanks in melbourne or online via greenlight.

    Using an eps blank with a stringer and resin research with a combo of sglass and standard 6 to 8 oz glass you could build an incredibly tough sup. Vac bagging not necessary hand lam would work and save you money and a lot of trial and error. Most surfers are concerned about weight which affects lam schedule but that wouldn't be as much of a concern if building a fishing sup. Vac bagging might help you save a few lbs on a sup but setup cost wouldn't be worth it for the few lb difference.
     
  13. el9surf

    el9surf Well-Known Member

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    Worst case link up with someone in the pensacola area on swaylocks.com that is already setup for vac bagging.
     
  14. CurtisWright

    CurtisWright Light, Strong, Cheap. Pick Two.

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  15. DuckNut

    DuckNut Brandon, FL

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    Here is what I know: infusion and bagging are two separate processes.

    Infusion is a method of transferring resin into the layer of fibers. To transfer you need pressure or create a difference of pressure from the atmosphere to the part.

    Resin Transfer Method (RTM) is a method where the resin is transferred from a container and infused into the fibers by a pressure pump, no vacuum. This requires a heavy inner and outer mold.

    Vacuum bagging- (prepreg) molding is a process where there are no resin transfer because the resin is already impregnated into the reinforcing material. You have to cook it in an oven though. A variation of this is VARTM- UV curing, another vacuum bagged process.

    Also, ordinary off the shelf resins and fibers will not work and you must have the correct pressures.

    It is, and the videos will show how easy it is but there is a lot of trial and error until you get it right. Keep in mind that if you use too much pressure then the laminate schedule has changed and may result in undesirable results of too thin of laminate and that will directly affect your final products stiffness
     
  16. lemaymiami

    lemaymiami Well-Known Member

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    Along with the great advice already given remember that dealing with composites (glass, carbon, kevlar, etc.) that different materials have different saturation and bonding characteristics... That's one of the reasons that early "kevlar" hulls (where the only actual kevlar used was in just a few places to replace roven woving) manufacturers had problems with the kevlar portions de-laminating away from other materials... not a small problem.

    I'll be watching this thread, always interested in hull layup...
     
  17. CurtisWright

    CurtisWright Light, Strong, Cheap. Pick Two.

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    Yea,  so far my thought is to set up on the coldest day of the year in my garage,  mix my resin with a little less hardener than is required for the ambient temp.   Hand lay all the fiber and resin into the mold, then try and get a release film, absorber and a vacuum bag over it before it starts to harden.    Then close my garage doors and fire up a propane heater to warm the room and help kick off the resin.

    This is why I want to start small on an SUP or Ambush sized hull.   I wanted to do this on my Fowl River 16, but I literally need 20 people to get it all in before the resin kicks.  About 10 wetting glass in the mold and the other 10 with clean hands handeling materials.   I think it is really cool how Bell Canoe's uses a carbon kevlar weave with Vynalester resin and no Gel cote.   They just put a UV inhibitor in the resin.
     
  18. DuckNut

    DuckNut Brandon, FL

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    Please post pics of how you heat your garage to about 250 degrees for about 4 hours...that will be a tremendous feat if you don't set the house on fire.

    If you are going to experiment - I would lean toward the UV curing because the resin won't kick until you turn the light on and cure it allowing you all the time you need to get it laid out properly.

    But you also need to calculate a layup schedule with a full understanding of all of the components strengths and shortcomings. Last thing you want is a cracked hull.
     
  19. CurtisWright

    CurtisWright Light, Strong, Cheap. Pick Two.

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    250 Degrees? With Poly resin on a 40 Degree morning you can mix about 22cc of MEKP per gallon and the glass wont start to cure for an hour and then it just gels and never quite hardenes. I closed up my garage lit the shop heater got it to about 110F and it cured PDQ.
     
  20. cutrunner

    cutrunner Cert. Yamaha technician

    I've watched a bunch of maverick hpx's being built. They use varis. Vacuum assisted resin infusion.
    That's the way to go. But crazy expensive. Seeing varis makes normal vacuum bagging look like shade tree building.
    Also got to see the ramcap process at Everglades, that's pretty cool as well