Weave or lots of layers of CSM

Discussion in 'Materials' started by Leon01323, Oct 8, 2011.

  1. Leon01323
    Joined: Dec 2010
    Posts: 95
    Likes: 1, Points: 0, Legacy Rep: 27
    Location: England

    Leon01323 Junior Member

    Hey guys

    Last post I was making a mould for a mountain board deck and now I've come to making the board. Made a test piece using 4 layers of 300gm foam core in the middle and then 4 layers again. Was not strong enough to take my weight.

    Was thinking I could do it with layers of 600gm Matt on the basses that each layer would be 1.6 mm and would try and get A good thickness.

    I was then tempted to use weave fabric but not used it before. I've heard it does not bond well together in layers and that would not be good. Is that true? Also is it a lot lot strong and i could use less layers and have a thinner deck.

    Any info would be great, thanks in advance :)
     
  2. Herman
    Joined: Oct 2004
    Posts: 1,618
    Likes: 89, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    There is not much info in your post, but I will try:

    Are you using polyester resin?

    My best guess at this time:
    -change to epoxy
    -increase foam thickness
    -use wovens, or better, UD on the inside, woven on the outside.
     
  3. Leon01323
    Joined: Dec 2010
    Posts: 95
    Likes: 1, Points: 0, Legacy Rep: 27
    Location: England

    Leon01323 Junior Member

    Sorry for the lack of info.

    Using polyester as epoxy will be too expensive for what i need.

    Will weave bond together like CSM then? Was only using foam as a bulking aid in the hope it would increase strength but had no luck.

    Will try weave like you say and see how many layers I need and will test as I go.

    Thanks
     
  4. Fanie
    Joined: Oct 2007
    Posts: 4,603
    Likes: 170, Points: 63, Legacy Rep: 2484
    Location: Colonial "Sick Africa"

    Fanie Fanie

    Polyester resin is as strong as epoxy - it is the glass that determine the strength, not the resin. The resin is not considered when calculating fiberglass strength, only the glass is considered. Epoxy resin can bend more than polyesrter resin, so unless it's going to bend a lot there should be little difference except the price.

    Only use woven, it is a lot stronger than chopstrand, and neater and easier to work with.

    The thicker the foam and the further apart the outer glass layers the stiffer (and strionger) the board will be BUT

    There is a relationship between the thickness and strength as well as the width of the sides from each other. If the board is wide you can make two narrower boards side by side so that there is a vertical rib or ribs spanning the length (or width depending which will carry weight best) inside the board which will add a LOT of strength.

    A 10mm foam will need a LOT of glass and will come out heavy

    A 100mm thick foam will be stronger and stiffer because the upper glass will compress to fold inside the bottom and the bottom glas will want to stretch around the top.

    You need to give the size as well as the weight you intend to carry on the board indicating the support points to a firberglass/marine engineer to calculate the best ratio, thicknes vs layers and have a safety ratio in there too.

    Post pictures, be interesting to see.
     
  5. tunnels

    tunnels Previous Member

    If you insist on using foam the density need to be really high as you fill get core shear if the panel has lots a bending taking place .
    if you want it stronger use triaxle 0/45/45 glass matt 800 grams ,2 layers each side and the core needs to be at least 18 mm thick .
    If its what im thinking a Balsa core maybe better for you rather than Foam !!and could cost less !!
    Resin to use !!! Vinylester is better than polyester and less exspensive than epoxy but has simular qualities . :)

    Going to exstremes with the glass ,400 gram uni directionall matt 3 layers each side ,just a little more complicated to build but will handle flexing better and could last longer .:p
    Need to post some pictures of what you got and are trying to make . :?:
     
  6. Herman
    Joined: Oct 2004
    Posts: 1,618
    Likes: 89, Points: 48, Legacy Rep: 1240
    Location: The Netherlands

    Herman Senior Member

    Fanie, see attached. This is a mountain board. It WILL see a lot of flex and abuse.

    As said by all 3 of us, skip the CSM, you will never get away with it. I have no idea of how "flexi" such a board should be, but a more advanced layup is what you need.

    [​IMG]
     
  7. tunnels

    tunnels Previous Member

    go man go !! what a way to die !! completely out of control!!!

    Oh my God whats next ??
    Forget the core and go with solid unidirectional glass and use vinylester resin . Yes it will be a little heavyer which could be a good things but theres going to be a ton of flex involved and twisting etc etc exstreme will be an understatment !! The place where your trucks are monted will need special treatment to take the enormous loads from the mountings The mountings are through bolted with 4 bolts ? they really need a steel base plate with another plate on the other side rather than just relying on the holes to carry such enormous shock loads But sure as hell id be using unimatt and making it to flex and twist . and not be solidly ridged . twist will last and not break to easly . Solid with no flex you could be walking a good part of the way down the hill . I hope you got video and you tubed it !! wow what a way to go yahoooooooo! anyone died yet ?? no dont think about carbon its like a carrot and will snap very quickly unless you find a composite engineer and you are prepaired to spend a wheel barrow full of money .
     
  8. Fanie
    Joined: Oct 2007
    Posts: 4,603
    Likes: 170, Points: 63, Legacy Rep: 2484
    Location: Colonial "Sick Africa"

    Fanie Fanie

    LOL, Tunnels, it's not even wet unless you wet it yourself :D
     
  9. m3mm0s rib
    Joined: Aug 2011
    Posts: 133
    Likes: 3, Points: 18, Legacy Rep: 57
    Location: GREECE

    m3mm0s rib Senior Member

    To get the desired result should be JUST 3 layers of mat 600 + 1 coremat 3 mm and again 3 layers mat 600 grams. All this will give you a total of about 10 mm. If thou and other coremat thickness increased from 3 to 4 mm. The weight of this construction is 7-9 kg per Μ2
     
  10. Fanie
    Joined: Oct 2007
    Posts: 4,603
    Likes: 170, Points: 63, Legacy Rep: 2484
    Location: Colonial "Sick Africa"

    Fanie Fanie

    The sailboat okes can sail upwind, right. Can you guys mountainboard uphill too or have you not advanced that far yet ?
     
  11. sabahcat
    Joined: Dec 2008
    Posts: 792
    Likes: 27, Points: 0, Legacy Rep: 273
    Location: australia

    sabahcat Senior Member

    What sort of foam?
     
  12. tunnels

    tunnels Previous Member

    Core matt is as useles as **** on a bull for something like that it will shear within its self and fall apart with all the abuse twisting and bending . Corematt does not like bending ! believe me .
    Corematt came on the market long time ago as a bulking core that would comform to shapes when wet and build thickness quickly for the building industry . It was never designed for what it gets used for or what people use it for decks hull side but never in the bottom !!!
    NEVER use it in the bottom panels of any kind of boat ! never!!never !!never !!!!
    Have seen the whole bottom outside skins blow off a boat from the bow at to the bottom edge of the transom !!,chine to chine!! .
    Just went bang and snapped off ,10 miles off shore . As luck would have it the inner laminate was strong enough to limp slowly back to shore and get the boat back on the trailer . I had the job of stripping everything out of the boat then i bought it real cheap and totally rebuilt the bottom with solid glass . :D:p:p
     
  13. m3mm0s rib
    Joined: Aug 2011
    Posts: 133
    Likes: 3, Points: 18, Legacy Rep: 57
    Location: GREECE

    m3mm0s rib Senior Member

    TOUNNELS I'm not talking about bottom but only where needed lightweight construction
     
  14. Leon01323
    Joined: Dec 2010
    Posts: 95
    Likes: 1, Points: 0, Legacy Rep: 27
    Location: England

    Leon01323 Junior Member

    Hey guys

    Ive tried to get as much info as possible to show you guys that know what your talking about. Hopefully i can learn from you.

    First off ive got a guy here who has made a board using a very simple mould and weave.

    http://www.wingsurferforum.co.uk/forum_posts.asp?TID=2264&PID=20374

    [​IMG]

    [​IMG]

    [​IMG]

    thats what got me on the weave idea as it seams he has done it but it does not look very well bonded. Also my supplier says on their website it does not bond well in layers as there is a tight weave. Also not sure which of these to use:

    http://www.cfsnet.co.uk/acatalog/Woven_Glassibre_Cloths.html

    next ive got one of my boards that i ride, its deck is solid fibreglass as far as i can tell and looks like matt but maybe you guys will be able to shed some light on it.

    [​IMG]

    below is the deck. it almost looks like it has been made up of several sheets of glass and then each layer stuck together as usually i cant see the layers when i make mine up.

    [​IMG]

    to give you guys some idea of the flex, on this board when i bounce up and down with my feet strapped in i can get it to touch the ground in the middle. If i dont bounce it is slightly flexy. Im 11.5 stone (73 kg).

    below is the prototype board which i tried with the SPHERECORE between the csm matt

    [​IMG]

    Not sure if that all helps or if ive just made things worse.

    Once again thanks for all the info guys your knowledge is vast:)
     

  15. Leon01323
    Joined: Dec 2010
    Posts: 95
    Likes: 1, Points: 0, Legacy Rep: 27
    Location: England

    Leon01323 Junior Member

    Any ideas guys?

    Thanks
     
Loading...
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.