I have a bunch of UD carbon fibre and some biaxial fibreglass which I’ll use.
I also have some bamboo and maple veneer but think the shape is too much for that (will test bag a couple of sheets and see)
I also have some Spheretex SBC composite core material which is a resin absorbent mat which adds thickness at about half weight of a normal laminate buildup.
Maybe use a core of that, for a central stringer, or maybe some thickening a near the edges…?
Not sure on any additional reinforcement in truck mounting spots.
Need to read your thread again and do some more research.
Kinda want to avoid using ply or wood in that area alone…
Bit worried the footpockets aren’t far enough apart, but with their depth and shape, wider stances will have feet canted together a bit, making it a bit more comfortable and better suited for bracing against accelerating and braking forces.
I weighed out the amount of carbon that build used and I think it was a bit wasteful, about 4550 grams carbon / sq m. I think a smarter application of core would give the stiffness required - I’m doing a test using expanded PVC foam board now. From what I read the thicker the core material the stiffer the laminate, it operates similar to an I beam in that the main strength comes from the carbon plies while the core maintains the distance between them.
The core stuff I bought wasn’t too expensive and was great when I used it on a mould I made. Just made some little gussets and stuff. Getting adhesion between edge layers and core is important I think, to resist shear loads. Balsa is also a decent option.
Fwiw I used aramid reinforcement under the truck mounts and in the drops. Carbon fails catastrophically when it goes while aramid “gives” and retains a portion of it’s strength. I think delrin does too.
Router again for the dropouts next, then the plan is to smooth and finish all of the rocker shaping and then route and sand in the long direction to form the concave.
Yup bending forces are resisted in this way, by tension at the base of the deck and compression in the top layers. Those forces are mostly occurring and being resisted centrally on the board between the trucks (on a longboard).
Other loads are being resisted nearer to the trucks in shear. For strength here, I think adhesion between layers in the laminate is more important.
Increasing the thickness of a board (even slightly) will have a significant impact on its stiffness. My simple dayjob example: a 140x45 (6”x2”) timber wall stud has around 3x the stiffness of a 90x45 (4” x 2”) stud. Keen to see how the foam core test goes
might have to get some of that in the stack
obviously like it thick
