This is my second carbon fiber project. The first was a skateboard for my son. This is a longboard for my daughter. We are not serious skateboarders/longboarder – I wanted to begin learning about composites and this seemed like a reasonable platform to start, with the option for straightforward shapes and less worry about critical failure like a bicycle frame.
This is a 48" pin tail with three layers of 3K Carbon Fiber on the bottom, two 1/4 inch stacked layers of DC Corecell 550 (totalling, of course, 1/2 inch, and only because I didn’t have 1/2 inch Corecell stock and two layers of 3k CF for the top. It was made from a mold from an existing unused wood board which i carefully sanded, prepped with multiple coats of Partall, release agent and then mounted with clay on plastic sheeting. I then coated it with a mixture of West resin and 205 hardener with fiberglass and silica thickeners and reinforced the mold with strips of 550 corecell and plain weave fiberglass to about 3/4 inch for stiffness.
After the mold completely cured I sanded any imperfections, buffed and repeated the Partall prep but used Fib release instead of PVA.
My first coat of resin was Wes105/207 with a thirty minute set at 68 degress followed by my three layers of CF, then my DC (double cut) corecell foam which I under cut 1/8 inch around and edge filled with a mixture of chopped CF, Kevlar and epoxy, equal weights. This gives better compresion on the external CF at the edges. I put my top layers of CF, then resin, release film etc. I place it in a uline 4 mil, 18 inch wide bag, sealed the edges and vacuumed with my cheap eBay used Gaast pump at 27 mm hg for 6 hours.
I should add I cut out the truck mountes in the foam and filled with chopped CF and West epoxy, again equal weights and smoothed it to prevent depressions. This is to prevent screw subsidence into the corecell (though 550 is pretty stiff it will still compression easily under load).
I waited twenty four hours after a cure at 72 deg, released the board, trimmed, sanded and recoated with West resin. I finished it with a layer of u pol clear coat for UV protection (wish I had that step professionally done)
Here is the mold
