Oops, make that 1.5 oz where ever I said 1 oz. I think the changes in materials over the years makes less of a difference that what Graham said, "From hand layup, to vacuum bagging, to resin infusion and/or pre-preg." Reducing the amount of resin using these techniques results in a hull that is just as strong yet lighter.
Ken H. On 1 March 2014 20:20, Ken Heaton <kenhea...@gmail.com> wrote: > The schedule for the 1990 37+ > > Below the waterline the layup was one layer 1 oz. chop, one layer 1 oz. > mat and one layer of C77K/200 Kevlar Fabmat (a blend of fibreglass and > kevlar 49) outside the balsa and one layer of C72K/100 Kevlar Fabmat > inside. This Fabmat is much heavier than the 1 oz. chop and 1 oz. mat at > about 2.47 oz. for the C72K/100 and 4.94 oz. for the C77K/200. This was > over 10 oz. per sq. ft. of reinforcing material not counting the resin. > > The layup was much heavier at the turn of the bilge across the (almost) > flat bottom of the hull to the keel sump as an additional two layers of > C77/200 Kevlar Fabmat were added and further, in the keel sump, the balsa > was replaced with two layers of Compositex. This was over 20 oz. per sq. > ft. of reinforcing material not counting the resin. > > Ken H. > > > On 1 March 2014 15:27, j...@svpaws.net <j...@svpaws.net> wrote: > >> I'm but an accountant not an engineer. Help me understand this stuff.. >> >> So if I use a 1990 34+ as the baseline, the hull was a composite of vinyl >> resin, presumably glass matt and chopped strand, balsa core and Kevlar. >> >> Now fast forward to 2000 and my early 121. The glass Matt has been >> replaced by E glass, balsa has been replaced by core cell, glass strand >> remains to add bulk and the Kevlar remains. Presumably this provides a >> lighter hull as the e glass is stronger than matt, core cell is lighter >> than balsa and requires less resin and the Kevlar remains the same. >> >> Fast forward another 10 years and we have epoxy, reinforced with carbon >> which does the job of Kevlar, matt, e glass and strand. The core cell >> remains. >> >> Am I even close? >> >> John >> >> >> _______________________________________________ >> This List is provided by the C&C Photo Album >> http://www.cncphotoalbum.com >> CnC-List@cnc-list.com >> > >
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