Infusion Q&A

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

  1. groper
    Joined: Jun 2011
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    Location: australia

    groper Senior Member

    All my infusions have been done with epoxy, so cannot comment on gelcoat print with PE or VE infusion...I guess the shrinkage of these resins may get a little. All i can say however, is that there is no noticeble print through when i infuse heavy weight multiaxial fabrics directly to a flat table mold using epoxy and zero leaks. If you have leaks however, you do get surface blemishes in the leaky area where there is tiny air pockets usually located between the fiber tows, so in this case i would expect the fibre to print through.

    have you considered your laminates yet?

    Are your laminates single skin or cored sandwich type?

    Do you have to adhere to a minimum glass hull thickness rule, above or below the waterline, and have you considered the same laminate will be considerably thinner with infusion vs handlayed?

    Have you considered the laminate thickness and strength properties of the infused laminate compared with current handlayed - can you reduce the cloth weight?

    If your laminates are heavier than 60oz - which they almost certainly are below the waterline - then you will actually use so much less resin, that it offsets all the infusion consumable costs and you will start to save money - provided you are shrewd when buying your consumables...
     
  2. Herman
    Joined: Oct 2004
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    Location: The Netherlands

    Herman Senior Member

    Pricing in larger volumes: Some 2 euro / kg for a DCPD resin, 2,75 for an ISO resin, and 4,50 for a VE.

    On shrinkage:

    There is 2 types of shrinkage:
    -shrinkage due to chemical reaction
    -shrinkage due to temperature

    In order to reduce shrinkage, keep temperatures low. (with infusion this is sometimes a challenge, with thicker laminates)

    Chemical reaction: just based on materials. VEs usually have lower shrinkage, but not all of them.

    The longer the product is in the mould, or postcured in the mould, the better the surface reflects the mould surface. You sometimes see a product demoulded, having a perfect surface, but after 2 days the surface has printed: chemical shrinkage.
     

  3. Steve W
    Joined: Jul 2004
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    Location: Duluth, Minnesota

    Steve W Senior Member

    Groper,i have 2 different boats i am looking at, the bigger one which i already own the female hull mold for (but probably wont start for a couple of years,it will be for my son and hes not ready yet)will have a basic layup of about 111oz plus a 3/4" core with a total of about 136oz down the centerline as designed, i will probably reduce the overall laminate but increase it down the centerline for beaching. The other boat we are thinking of would be a 8.5m cat so the laminate will be quite light,well under 60oz.
    Herman, good points about shrinkage, when you say that not all VEs have lower shrinkage, this is where trying to find out what others are using and how it is working out is important to me, i used to manufacture snowboards years ago and we went through a lot of different epoxies (and heartache) before finding finding one that did what we needed it to do even though some were marketed specifically for the purpose. Unfortunatly it was a very secretive industry back in those days and you pretty much had to figure everything out yourself, much better now with forums like this.

    Steve.
     
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