Great advice Carbon Cactus, about the symmetry, it's good to have it reminded , I tend to forget how important it is, depending on the shape.

Emulsion bound and epoxy is a deffinite no go.
I might be wrong but if you use a core material, it preferably wants to be a symetric layup, so to get it close to 3mm:

195gsm CF
195gsm CF
2mm Soric
195gsm CF
195gsm CF

If you dont do it symmetrically, one side will be stiffer than the other and cause warping. Again this is what I've heard, I might be wrong.

You could use your CSM, but you would have to use a polyester infusion resin, like the one from east coast, or a vinylester, tight corners might be an issue, but it depends, a bonnet might be fine. If you use a polyester, you'd kill 2 birds with one stone and have UV protection.

Thank you Warren,

It would need to be a chopped strand mat which is powder bound.

It would be very difficult to infuse properly as the unwetted CSM is stiff so hard to get into awkward shapes.  Generally CSM is wetlay so as you put resin on it, it soaks in and the CSM goes floppy.

I would suggest you use soric.  The part will be lighter and stiffer.  If you want to add more layers than just the CF then woven glass is the way forward.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

...or do we have to use woven glass instead ?