preform stringers???

Discussion in 'Fiberglass and Composite Boat Building' started by clynad, May 9, 2012.

  1. clynad
    Joined: Apr 2012
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    clynad Junior Member

    Does anyone have any experience to share regarding with preform stinger systems such as Creative Form Products (CFP.inc) or Prisma Composite Preform???
     
  2. tunnels

    tunnels Previous Member

    :idea:Just make your own !!!:p
     
  3. Herman
    Joined: Oct 2004
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    Location: The Netherlands

    Herman Senior Member

    When used in a curved situation, such as a boat hull, the UD on top tends to crinkle somewhat, which is undesirable.

    I like the foam blanks in the right shape better, where the customer can apply their own fabrics.
     
  4. clynad
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    clynad Junior Member

    thanks for the replies guys
     
  5. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    These pre-formed shapes can be handy, but can also have some draw backs as mentioned. Considering the costs, unless a large project was underway, where labor costs could be justified by speed increases, they are considerably more costly ten just cutting foam and tabbing it into the laminate.
     
  6. tunnels

    tunnels Previous Member

    what is so complicated making a poly urethane foam shape ,sanding it and sticking it in the place where it is needed and then painting a coat of resin over it and then glassing !!100mm onto the hull up the side and folded on top then do the same for the other side!!! 10mm onto the hull , up the side and fold on top each layer need to form a double up on top ideally you need to use 10mm wide 900 gram unidirectional tape full length fron one end to the other as straight as possible 5 layers is a good figure and the repeat the glass again 110mm onto the hull up the side and fold over the top and same on the other side !!.
    Now instead of using the woven roving where only 50%0f the glass is rear doing its intended job i would use the same weigth double bias where 100% id doing what its there for . ooops did i hear rumblings about always using woven roving ?? well this is a classic example of what can happen when a job is not done properly!! what are a couple of the thing wrong here ??
    any one want to have a guess ??:?::(
     

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  7. ian_upton
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    Location: Grand Blanc, Michigan

    ian_upton Junior Member

  8. Silver Raven
    Joined: Oct 2011
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    Location: Far North Queensland, Australia

    Silver Raven Senior Member

    PU foam for stringers

    'tunnels' - you can't possibly be serious - surely. PU - for anything in a boat. It is not 'closed cell' - not in any way - under a stressed situation. Why would you use it? Why would you leave it in situ?? It will absorb water regardless of how you coat it. Why not make the shape - that way if you must - then get rid of the foam & just glass the shape into the required position. Your technique is about 100 years out of date. jj
     
  9. tunnels

    tunnels Previous Member

    You are on a differant planet my friend .time you went and had a look at what really goes onin the world !! Its been done this ways and still is being done this way every where in the world!!, go lift the bonnet on any big power boat and pu foam will be used as a former . right at this moment I am part way into a 95 foot boat and have 10 stringers 28 mtrs long all done like this . Even racing yachts we do same way and some of them have 6 or 9 layers of carbon fibre uni's running along the top along with 3 layers of double bias glass .
    They will only asorbing water if who ever makes the stringer dosent do there job properly . "BAD WORKMANSHIP" its called !!.
    More than 90% of fireglass failures are from bad workmanship and 10 from poor choice of materials to do the job !!
    1972 was the first time i ever did this and in a couple of weeks from monday we will be doing the same thing again .
    Now as you were saying ???:?::p
    I just looked and see your your a damned OZZIE !! that figures !! gidday cobber !!! the only nation on earth the shoots and eats its national symbal (the kanagaroo ) !! shove another roo on the bar be mate !!
     
  10. tunnels

    tunnels Previous Member

    dont forget to give the bonding to the hull plenty of glass and resin and should be 150 mm wide bond to the hull and use double bias not 0/90
    Only 50% of the glass is going round the corner and doing any work the rest is there for ballast !! :D:p
     
  11. clynad
    Joined: Apr 2012
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    clynad Junior Member

    I started this thread because i am looking into a 18' boat mold that comes with a set of stringer molds i would like to compare the price of preforms to the hassle and price of customizing.The real question for me is will the preform be cheaper than coating the mold with some kind release material (or layer of glass), foam it out, trim the bottom to the hull profile then install them in the boat will a proper tabbing runoff (Dave Gerr specification). My hope is that i wont be left with a big "smile" speaking in "colorful language" how that nice video on the Prisma site made it look soooo easy.
     
  12. tunnels

    tunnels Previous Member

    When you say stringer mould you are refering to a grid system ?? molded of glass and fitted inside the hull and floors etc etc are fitted over the top !!????
    That is the best you can get !! dosent come any better !! grid is glassed in and dosent rot ,dosent get wet ,and become heavy ,dosent need foam any where round it !! your discription is a little confusing !!:rolleyes:
     
  13. clynad
    Joined: Apr 2012
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    Location: Bahamas

    clynad Junior Member

    tunnels this defiantly ain't a grid system looks more like someone made a tool using a pair of 2x10 engine bed stringer.
     
  14. tunnels

    tunnels Previous Member

    post some pictures !!

    Ok so got ot wrong again !! post some pictures and take away the confusion !!:D
     

  15. clynad
    Joined: Apr 2012
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    Location: Bahamas

    clynad Junior Member

    the is stored an another island (150 miles away) i took a look at it last week but sorry no pics
     
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