Carbon seat build

I think one of the most critical and difficult to design and build , I have some experience with composites and shaping EPS high density foam

i have used Epoxy but hand shaped surfboards. But the seat needs to be right the for the surf hydrofoil and the downhill bike

the only way  will know what works is by sitting in it! make mistakes and start again sometimes you just know when a seat works at first i will work on the Downhill bike

after that the hydrofoil but i need to go through the process for one first.

I'm using the CNC to shape the base using 60mm XPS high density foam which now days is used for allot of building applications

it is high density and machines real,y well i have to machine the seat in three parts glue them together then fine shape by hand. before applying the carbon

The seating was always going to be a challenging e exercise for me, I have experience with epoxy from my able bodied surfing years making boards but not carbon so it will be the case build one then build another fixing each problem as it rises

Once again I design a seat I think will work using fusion 360 trying to get my measurements I think will work but you never know till the final seat is physically in front of you letting you know if you are right or not so the first seat is a template for what to do in the next one right or wrong

As I only need the surface to glass the carbon into I extend to design it so I have the outer body to glass then once the glass and carbon sets I should be able to peel off the carbon shell in theory but I’m not to fused about production at this point

For the core I am using  XPS high density foam the kind you can buy for insulating houses the cost €70 1000x600x60 around 8 which is loads the epoxy resin I’m using is west coast epoxy resin and the carbon I got from AliExpress

Using the CNC and machining the seat in 60 mm segments. So we have bottom middle and top then we glue each segment of the forming block together for our carbon sand the slight discrepancies  out  from each segment

Once satisfied with the forming base I leave a square block in the center so I can mount it for glassing vice it into a board then prep the carbon and epoxy

As with all things new the XPS foam cuts worked well, I glued them together and with the west cost epoxy used carbon to create the first layer using standard carbon weave

 But in retrospect I should of glassed the foam first then used a release agent before using the carbon without this the carbon adhered too well to the foam so I needed to cut the foam out which looks messy but as it’s the prototype I was pleased with the result I feel the seat will fit tightly to my hips and was and is a better result than I expected.

I coated it in another layer of glass and sanded it down again I will put on a second layer around. The back and on the flat part I will add a few disks of stainless steel giving strength when it’s bolted in

 Doing more research I have discovered better methods of casting the core still using XPS but coating it in release agents afterward a hardened shell with an epoxy release wax creating a reusable mold allowing the glassed carbon shell to be removed with the first layer put down