I built a foilboard (90x42x1.6cm) with wood from my buddy's mill (western Red cedar). Started with 1x4 boards, chopped to length, glued together 2 layer bent lamination, cut outline. Drilled holes, filled with resin+microballoon, Fiberglass and epoxy 4 oz cloth, sand down and clean resin, last layer of resin, redrill holes, lay down deck pads.
Lessons learned: I did top side jointer, bottom side planer, jointer side and jointer other side- I should've done table saw for the last side.
This led to a slight error in the boards- slight mis alignment, and I pressed it together with my glue-up, but caused some minor warping in the wood.
I cut my length first- I should've left an extra 10cm or so extra, give some fudge factor.
I did an ad hoc press for the glue up- i did everything at the same time and it was a bit sloppy. In hindsight I think I would've created a mould for each set of boards then press each pair individually. Then glue the 5 sets together into the board shape.
Warped boards led to more work to sand the board flat, and even then it wasn't perfect. When I laid down the fiberglass there were some minor voids left. Suspect they're just cosmetic but could've done better.
Drilling/filling holes with microballoon: minor shape errors led to some perceived misalignment of the foil mounts. Just a couple degrees, but not perfect. Microballoon really expands the epoxy, I used a lot of resin with test batches... Could've used a much smaller amount.
First layer of resin is the most important by far. I used 6 oz of resin for my first layer. Seed to work well- first layer is just to get the cloth to stick to the wood flush, not to fill the coats.
I had the cloth float off the surface where it wasn't totally flat... Could've got a syringe and injected epoxy into the void, but didn't.
Poured way too much epoxy on my last coat on the bottom, just ended up sanding it off anyways.
Biggest drill bit in the shop was 3/8 for holes, should've used 1/2. When I went to redrill for 5/16 bolts ended up cutting into wood a bit and having to epoxy the wood to waterproof it.
So, in hindsight I burned a bit too much material on v1.0 but seems like it's a functional product.
Next step is taking it to the water and seeing if it'll snap in half!