Demolition phase 2 is complete. The Mako interior lays bare and scoured clean like fresh sand exposed at low tide. She's ready, bow out, eagerly awaiting the gurgling lift of incoming tide. This build is rushing in on the visible horizon. Next step, shore up the hull with a new schedule of fiberglass.
In stripping away the detritus, we've weakened this hull considerably. Our first order of business, stiffen her back. We want a rock solid base layer, so we consulted
Prisma Composite Preforms, experts in composite construction. They've advised a new layup which will form the foundation for their
preform stringers and stiffeners. Modern designs achieve a lightweight, stiff hull via a cored laminate construction. But this vintage Mako was straight fiberglass without core. Prisma engineers devised an improved schedule of fiberglass that is stiffer than original. The first application will be Quadraxial cloth, followed by 24 oz 0°x90° cloth which Prisma distributes. The Quadraxial cloth is 4 layers in one cloth, each weave alternates a different direction (0°, +45°, -45°, 90°). We'll elaborate more on this in the next post.
We had yet to get our hands on the quadrax but expected a heavy cloth where it's drapability is stiff like
biax. Heavy cloth poses a challenge for hand layup - air pockets. Small voids were throughout the original build. Grinding off the old roving revealed loads of air pockets, particularly at the hard turn on the
chines. In a morning coffee gam session TJ and I leaned over the transom and threw out some problem solving ideas- what if we smooth the sharp transitions with a
fillet. The fillet will ease the bend in the cloth maximizing the bond.
We mixed
West 105 /
205 with a hefty dose of
milled glass filler and filled the V in the bow. This mixture needed something more to prevent sagging, so we added enough
407 low density filler to make it stay put on the sloped sides. We also spot patched some voids in the stern with the remainder of the batch.
The gray in the bow is the milled glass mix, the shiny brown is the same mix with 407 added. Once cured we passed the sander over it with some 120 grit and faired this to a fillet-like easy curve.
This hull is clean and ready for the big show. Time to dress her up with some Quadrax!
In stripping away the detritus, we've weakened this hull considerably. Our first order of business, stiffen her back. We want a rock solid base layer, so we consulted Prisma Composite Preforms, experts in composite construction. They've advised a new layup which will form the foundation for their preform stringers and stiffeners. Modern designs achieve a lightweight, stiff hull via a cored laminate construction. But this vintage Mako was straight fiberglass without core. Prisma engineers devised an improved schedule of fiberglass that is stiffer than original. The first application will be Quadraxial cloth, followed by 24 oz 0°x90° cloth which Prisma distributes. The Quadraxial cloth is 4 layers in one cloth, each weave alternates a different direction (0°, +45°, -45°, 90°). We'll elaborate more on this in the next post.
We had yet to get our hands on the quadrax but expected a heavy cloth where it's drapability is stiff like biax. Heavy cloth poses a challenge for hand layup - air pockets. Small voids were throughout the original build. Grinding off the old roving revealed loads of air pockets, particularly at the hard turn on the chines. In a morning coffee gam session TJ and I leaned over the transom and threw out some problem solving ideas- what if we smooth the sharp transitions with a fillet. The fillet will ease the bend in the cloth maximizing the bond.
We mixed West 105 /205 with a hefty dose of milled glass filler and filled the V in the bow. This mixture needed something more to prevent sagging, so we added enough 407 low density filler to make it stay put on the sloped sides. We also spot patched some voids in the stern with the remainder of the batch.
The gray in the bow is the milled glass mix, the shiny brown is the same mix with 407 added. Once cured we passed the sander over it with some 120 grit and faired this to a fillet-like easy curve.
This hull is clean and ready for the big show. Time to dress her up with some Quadrax!
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