• 1st April 2007 - By greg

    I covered the Styrofoam bulkhead shapes with a layer of fiberglass roving using a light coat of spray glue to hold the fabric in place while I fully whetted it out with epoxy resin. I wanted to make the bulkheads light but strong, so I vacuum bagged the wet layups.

    I use Elmers spray adhesive for a temporary bond when I know that I will be using a vacuum bag to keep the whetted fabric next to the form. This glue tends to dissolve when epoxy is introduced, so it does not seem to clog up the weave and prevent epoxy from fully whetting out the fabric and bonding to the form. As you can see from the photos, Elmers glue allows me to wrap the form up nicely – kind of like wrapping a birthday present. I use 3M high strength 90 when I’m not using a vacuum bag, as it does not seem to dissolve with the epoxy resin and the whetted fabric won’t lift up or peel off the surface. the problem with the 3m 90, is that since it does not dissolve, the epoxy doesn’t fully soak into all of the weaves in the fabric – it seems to wet out about 75% of the fabric though, so probably more composite material is required to offset this. I’m not sure – it would be interesting to do some testing some day and find out exactly how much various spray glues impact on the strength/weight ratio of composite materials and epoxy resin.

    They came out really nice – light and strong and tightly wrapped in glass. I bonded them into the kayak hull using epoxy/micro and radiused the inside corners nicely. Now I am going to place a strip of fiberglass roving along the joins to further solidify the bulkheads to the kayak.

    I filled the bow and stern compartments with Polyurethane expanding foam. This foam is buoyant enough to support 60 lbs of weight per cubic foot. I estimated that 2 square feet of this foam should be good enough for Within-24, since Within-24 won’t feature the top deck. I’ll add more foam in the bow and stern compartments of the top deck, plus the deck has quite a bit of Styrofoam as it’s core, and will probably float all on it’s own.

    The reason for these two solid floatation compartments is if the boat were to completely flood, it would still stay afloat due to these two sealed off, solid buoyancy areas. For Within-24, since there aren’t any additional compartments filled with air, I’m thinking of strapping in some air filled water bottles under the soft deck just in case.

  • Leave a Reply