: I'll defer to your experience but I wonder how much of what you're describing
: is cosmetic as opposed to actual depth a gouge takes into that ablative
: layer and how far the gouge is going before it starts into the glass. Also
: I wonder if your graphite/epoxy/silica coats are substantially thicker
: than comparable clear coated boats. Is it possible what you interpret as
: resistance to scratching is actually low visibility of scratching with
: less ability to discern damage to the underlying glass laminate and wood?

: In other words line up three test panels all with the same thickness of
: epoxy/glass. One with 6oz glass and three thick fill coats then sanded and
: varnished. One with glass then graphite/silica fill coats of the same
: thickness. One with glass plus lighter glass and minimal fill coats and
: varnish to approximate the same thickness/weight of the other two. I'm
: assuming your graphite/silica mix is thicker than regular epoxy and that
: you are putting on at least two coats. Basically ensure the thickeses of
: epoxy above the glass is the same as on the thicker graphite mix. With the
: double layer with lighter glass and thin fill coats can ensure the thicker
: glass layer panel isn't over weight.

: Then get a big cinderblock and slide it back and forth some set period of
: times followed but suspending the brick and repeating some
: glancing/gouging blows.

: I could see the graphite sliding over rocks with a more slippery layer could
: pass you over and not stop on the rock or in the case of sand that it
: would slide over more easily but when it comes to the kind of sliding
: impacts that dig into glass and depress the wood I wonder how different
: the actual depth of the gouge is. With a varnished surface every scratch
: of any kind shows up and the varnish begins to peel of along the keeline
: leaving an obvious wear strip. With the graphite you're never going to see
: that whitened scratch or strip of missing varnish, it's just more black
: stuff but that isn't exactly a measurment of wear, ie. depth of the
: scratch/gouge.
: Also any kind of gouge that dings the wood but doesn't tear into the glass
: won't be visible on the graphite anywhere as much as varnished epoxy.

: When I made a kayak for a friend I wanted the bottom to be as maintence free
: as possible but she lived where it got very hot and it was likely the
: kayak would be sitting outside in the sun upside down. In 95 degree
: sunlight things get too hot to touch. So I did the bottom with two layers
: of 4oz s-glass, two thin fillcoats, lightly sanded then three white tinted
: fill coats with a bit of silica. Sanded and painted yellow. That way there
: would be a depth gauge for scratches but there would still be some UV
: protection where the paint peeled on the bottom. Basically I went for
: thick ablative tint coats on the very bottom and not much on the sides.

: Like I said my experience with graphite is minimal on two boats where it was
: just along the center strip on an s&g kayak about 2"-3" at the
: widest and it looked like it got scratched just like the varnish except it
: wasn't as noticable next to the varnished wood scratches.

It's not like I'm selling this process

And that sounds like a reasonable test. Right now I don't have the time to do this. Just reporting on experience from a process I copied from someone else.

Bill H.