Tried a different approach for the lid to the board.
I wanted to work with carbon so I got some 600g cf and a core material named lantor Soric LRC 3mm.
In order to make the lid fit the board 100% I started by cutting out compartments for batteries and so on. After that was done I filled the compartment with styrofoam.
I used self adhesive vinyl as a release layer on the board and then started to work with the vacuum process.
Cut the fiber and the core to correct size. Lay one layer of 600g on the vinyl. Add epoxy.
for the core material I used a brush to help the epoxy to get on both sides of the material before laying it on top the the carbon.
I reinforced the edges with carbon strips and lastly added the final layer of carbon.
Connected my refrigerator kompressor and waited for 12h, I used 720g west system slow epoxy.
The final lid is approx 590x425mm, 8mm think and a perfect match to the board. Weight is 1kg.
It’s very strong and I thing one layer of 3mm would have been enough since I have support in the compartment.