[Captain Ahab Jr]

I've been designing and using carbon composite materials for nearly 20yrs now and from your description I don't think its the right choice of material for you.

Can you go into anymore detail about what you want to make, does it see any temperature, impacts, what sort of spherical tolerance are you after, how many do you want to make. The more information you can give the easier it will be to choose the right material.

You may want to look at an alumnium loaded adhesive, Hysol 9394 is quite strong and I guess could be cast but you may run into problems with it not curing or curing too fast with the size of volume you are looking at.

There are also quite few good rapid prototyping alumnium loaded materials such as Windform XT, very strong and there would be no tooling or mould needed.