I want to make a flat sheet (or rather block) of carbon fiber that is 3cm thick? It's not a big block, roughly 7x7cm. I can only imagine infusion would be pretty useless for this as vacuum will have hard time pushing down that thick of a sheet so I'm thinking wet lay up and put something really really have on top to compress. What say you? Also, most importantly, how many layers do you think i'm gonna need to build that kind of thickness?

Hi,

Normally I get around 1 mm thickness from 4 layers of 200 gsm twill ..

I would simply do a test ... Cut out 10 7 x 7 cm pieces of your 285 gsm cloth compress it in a vise between two pieces of steel plate/ other hard material, and measure the distance between the two plates... I guess you will need the plates to press the "stack" anyway   Make it 8 x 8 cm or a bit more to be able to remove the outside "fuzzy" edges ..

Add layers until you get the desired compressed thickness ...  add epoxy ...  cure ... Done 

I make quite a lot of cloth "micarta" for knife handles, using both Epoxy and Polyester... I have two 20 mm thick stainless steel plates to compress it between.

I lay up blocks of about 1 cm thickness ,,, a couple of layers, then soak with resin, then more layers.. .e.t.c.  

It all begs the question:    Why make a 3 cm x 7 x 7 cm CF "block" ....  The same block in hard aluminium will be as strong and probably lighter...

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