Infusion Q&A

Discussion in 'Fiberglass and Composite Boat Building' started by jim lee, Dec 17, 2009.

  1. Herman
    Joined: Oct 2004
    Posts: 1,618
    Likes: 94, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    The advantage of clamping early is that the Vf will be higher and more consistent, yet not wasting resin. However, it is a bit of a gamble when to clamp. At 80%? or perhaps 85?

    There are other options to get a good Vf, but these waste more resin, but take out the guessing factor. It all depends on the preference of the operator...
     
  2. groper
    Joined: Jun 2011
    Posts: 2,483
    Likes: 144, Points: 73, Legacy Rep: 693
    Location: australia

    groper Senior Member

    Thanks for the reply Herman, but im still not sure what this means...?

    What do you mean by "its a bit of a Gamble"?

    Is it possible to starve a laminate of resin by clamping too early? I dont mean starve as in leaving dry patches near the part edge where the resin front finishes; - i mean starve as in pulling too much resin from the entire laminate to wet out the perimeter and leaving the entire part with a slightly dry laminate, you might see this as fibre whitening etc?
     
  3. groper
    Joined: Jun 2011
    Posts: 2,483
    Likes: 144, Points: 73, Legacy Rep: 693
    Location: australia

    groper Senior Member

    Just wanted to add a link to this excellent thesis on vacuum infusion;

    http://www.library.umaine.edu/theses/pdf/KenersonJE2010.pdf

    It explains the process in great detail and provides sources and solutions to common problems encountered including inter-tow and intra-tow void formation. Its a comprehensive paper, quite long and detailed, but an excellent resource in every respect.
     
    1 person likes this.
  4. Herman
    Joined: Oct 2004
    Posts: 1,618
    Likes: 94, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    Clamping too early might leave you with a partially unfilled part. The high Vf will not likely get dried out.
     
  5. groper
    Joined: Jun 2011
    Posts: 2,483
    Likes: 144, Points: 73, Legacy Rep: 693
    Location: australia

    groper Senior Member

    I asked this question earlier (about resin starvation) and my quest to find an answer led me to that paper i linked to in my previous post.

    I found the answer/solution to a problem i was noticing in some of the infusions ive been doing. I thought it was caused by clamping early, but it was not the case, nor was it caused by numberous other causes i investigated. The fibre whitening and micro void formation i was getting in places is linked to the resin flow speed - too fast and you get micro voids in the tows, too slow and you get voids between the tows... to get the speed right you need to do testing, and control the speed via the viscosity of the resin (temperature), or the permeability of the stack (change flow media etc), or by the pressure differential etc. I was only getting the intertow voids occuring near the edges of the parts infused from center towards the perimeter as the flow slowed down towards the end of the infusion (which is why i thought it may have been from clamping early). The middle of the panels were not affected.

    Theres heaps more info contained in that paper i posted earlier, such as vacuum reduction after clamping and Vf, vertical height and resin pooling vs Vf, formulas for calculating ideal flow speeds etc the list goes on... well worth a read...
     
  6. Styrofoam
    Joined: May 2012
    Posts: 16
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Thailand

    Styrofoam Junior Member

    Cant quite find an answer for this but is it possible to vacuum form a hull that's really thick? Say 10mm or 20mm of just fiberglass mats laid down no core no nothing just fiberglass.
     
  7. groper
    Joined: Jun 2011
    Posts: 2,483
    Likes: 144, Points: 73, Legacy Rep: 693
    Location: australia

    groper Senior Member

    Yes , and its a he'll of alot less labour too.

    Also probably cheaper as you will use less resin...
     
  8. Herman
    Joined: Oct 2004
    Posts: 1,618
    Likes: 94, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    Thickest I have done is 4" (100mm) single skin glass. No problem.

    If fiber amount is what you are after, you will save loads on labour and resin, but the part will be thinner than a hand laminated part, so will be less stiff.

    If you add fiber so the part will be just as thick as the hand laminated version, there will be more fiber and less resin, and will be heavier, stiffer and stronger.

    Alternatively you can look into adding a core of some sort, which will save on resin, labour and weight.

    Keep in mind that laminates that thick might generate considerable amounts of heat. Adjust your cobalt levels and choose slow and low exotherm peroxides, perhaps even add some CU8 solution to cut down on exothermic heat.
    When using epoxy, choose a slow one, that does not generate too much heat.
     
  9. Styrofoam
    Joined: May 2012
    Posts: 16
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Thailand

    Styrofoam Junior Member

    Thanks for the answer chaps. Still find it incredible but thinking logically its just more volume of vacuum thus more resin needed to fill the space. Currently trying to get my hands on David Gerr - The Elements of Boat Strength: For Builders, Designers, and Owners

    Need to figure out stringers, scantling, bulkheads hull thickness etc. But having a core is the way to go with all stringers, scantling and bulkheads infused in one go with the hull.
     
  10. rawleyjerel@yah
    Joined: Apr 2012
    Posts: 25
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: United States

    rawleyjerel@yah Junior Member

    experienced infuser

    if you would like you can email me any questions you may have about infusions ive done hundreds! ive infused other things as well like jet intakes for a submarine for the us navy and further more i am currently unemployed and looking for work so if you need a good infusion man ---- lol anyway my user name is my email address feel free to write and ask me anything i will be more than happy to answer them for you.rawleyjerel@yahoo.com
     
  11. rawleyjerel@yah
    Joined: Apr 2012
    Posts: 25
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: United States

    rawleyjerel@yah Junior Member

    infusion confusion

    it is also possible to reinfuse to rid yourself of any dry spots or resin starvation would you like to know how?? just email me and ill answer for you. did you use marine clear gel? clear gel alows you to see any dryness in the part. i was trained on infusions by bill seeman himself(bill seeman invented the infusion procces that used to be called scrimp wich stands for seeman composite resin infusion molding process) but hi patent ran out and any one can infuse now feel free to contact me at rawleyjerel@yahoo.com i will answer any questions you may have
     
  12. wadeed
    Joined: Sep 2006
    Posts: 51
    Likes: 1, Points: 8, Legacy Rep: 27
    Location: egypt

    wadeed Junior Member

    sea star

    15 years building hand layup speed boats 16ft to 33ft and i am thinking of vacuum infusion
    i read a lot and watched many you tube videos but every time i feel i have got all about it i am surprised with a new problem
    the problem now is the speed of infusion how can i decide about it speed and control it as a sample will differ than the mold
    also what about using carbon and kevlar and R and S glass in reinforcement with ve resin:D
     
  13. tunnels

    tunnels Previous Member

    Personally i would think even longer and harder before comitting myself to using infusion . theres more than meets the eye . its all the unspoken things that have to be found out about . Carbon and kevlar are non mixers as they are opposites !! one stretchs and is strong enough to simply pull out of a resin thats been used and the other has no stretch and in a resin starved situation is as brittle as a carrot . so why the hell try mixing the two . I have never found anything that cant be build just useing glass and ve resin .:?:
     
  14. wadeed
    Joined: Sep 2006
    Posts: 51
    Likes: 1, Points: 8, Legacy Rep: 27
    Location: egypt

    wadeed Junior Member

    trying to improve the strength and lower weight
    never worked with them but read about them so was thinking of using them
    with infusion i read as the skin gets thinner from the pressure it gets more breakable so should i increase thickness th:)an hand layup
     

  15. wadeed
    Joined: Sep 2006
    Posts: 51
    Likes: 1, Points: 8, Legacy Rep: 27
    Location: egypt

    wadeed Junior Member

    do you know R and S glass of owens corning
    does it have same problem of kevlar and carbon or it can mix with csm and wr without problems
     
    Last edited: Jun 28, 2012
Loading...
Similar Threads
  1. EngineeringEC
    Replies:
    13
    Views:
    1,006
  2. Florida Boat Guy
    Replies:
    15
    Views:
    2,092
  3. ber1023
    Replies:
    2
    Views:
    1,118
  4. fallguy
    Replies:
    11
    Views:
    1,261
  5. John Slattery
    Replies:
    14
    Views:
    1,618
  6. Steve W
    Replies:
    33
    Views:
    2,214
  7. weldandglass
    Replies:
    1
    Views:
    870
  8. Chotu
    Replies:
    8
    Views:
    1,208
  9. weldandglass
    Replies:
    2
    Views:
    1,148
  10. weldandglass
    Replies:
    6
    Views:
    1,609
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.