Noob kite surfboard build thread

Build Threads 2023
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Beginner shaper here!

Last year I made myself a simple cnc machine to cut surfboards (mostly interested in making boards for kiting). Building the machine took a few months, building a decent 3d model took another few months and … now I have some boards that I want to laminate. Honestly, I expected the lamination process to be way easier… I hope I can get some help here regarding that.

Here is the model I’m working on:

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The board is 5’2" stringerless EPS 200. I bought the foam from a construction company, they sometimes make black foam with graphite… This was the first white batch after the graphite batch, so now all my boards have these funny black dots… I hate them, but it is what it is.

The first board I laminated:

  • deck: 2x 4oz s-glass + 1x 4oz biaxial e-glass
  • bottom: 1x 4oz s-glass + 1x 4oz biaxial e-glass

I used sicomin clear evo epoxy. Mixed it with silica microspheres to seal the board before laminating.

It turned out super light (<2kg without the top coat) and super flexible, and seems reasonably strong. But kiting on a surfboard is rough, so I ordered some innegra for my next board to add impact resistance.

Questions:

#1. I bought this carbon tape that I want to use as a stringer to add a little more rebound to the board:

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The carbon part seems to be glued to a clear plastic tape. How do I laminate this to the board? The plastic doesn’t seem to absorb any epoxy. I found a suggestion to use 3M super 77 glue, but I’m totally not sure if this is going to work. Even if the glass binds to this plastic tape well, I will be relying only on the 3M glue for laminating the tape to the foam. Having a lot of doubts about this.

I tried to separate the carbon from the plastic, but apparently it wasn’t exactly designed to be separated )

#2. The biaxial glass has this strange texture when laminated:

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Before applying the top coat, I know I have to sand it, otherwise the epoxy is not going to stick well. But the grooves of the biaxial fiber seem to be really deep… If I sand it flush, I will remove half of the glass… loosing strength. How much should I be sanding exactly before applying the top coat?

thanks!

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Re: Item 2, your fill coat is intended to fill that in completely. Typically, though, surfboard building is not going to use that type of biaxial fiberglass. I would just follow through with a fill coat/hot coat and hope for the best… You can always sand that out and add some more later if you need additional filling.

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Sanding will remove fiber and defeat the purpose of your biaxial cloth. I’m no glassing pro but the biaxial lamination looks rough enough for decent mechanical bonding.
For a tough deck surface in the future, you might try a cork sheet/skin over and under FG on your deck.
“ Cork is also able to absorb a lot of punishment. Its cells have a unique 14 sided polyhedron structure that can be compressed to 15% of their normal volume and then regain most or all of its size and shape slowly.”
I would want carbon fiber laminated directly to the underlying FG.