I am thinking to try a vinyl ester  infused soric and carbon mould for use with pre preg processing.

Laminate might be 6 layers 400g carbon each side of a 4mm soric (maybe 2 of 4mm soric in areas) to make a thicker stiffer mould.

Anybody tried using a soric mould like this? I know there maybe be air left within the soric cells but it all very well supported? Heat/expansion??

Or should I use a few layers of flow mesh or shade cloth and leave in the centre of the laminate? This would mean no air in the laminate leaving a core of resin/plastic mesh.

I have several soric sandwich moulds. Most of the times I use the for elevated temp infusion, but some smaller ones for prepreg too. Most are epoxy based and infused, but some are vinylester/polyester handlaminated. Either way I usually use soric coremat, because it leaves no hex pattern and is much lighter than most other soric variants. 6 layers should be enough to avoid print through anyways. Must be a giant mould if 12 layers of carbon are not stiff enough. For me coremat infuses quite well, but off course needs flow media. Dimensional stability is good, but I tempered them carefully.

Ive used Corecork in infused moulds before. Bit different to Soric, but similar enough. 

Are you using a vinyl gelcoat John? Or just raw surface? If using a gelcoat then you'll be all good as you can sand/polish out any print through from the core. Air content in the core shouldn't present itself as an issue, 6 layers of carbon is plenty to resist blistering.

Ok I'll probably do this.

Vinyel ester gel, csm vinyl ester skin layer, infused vinyl ester 5 x 400g carbon each side of 1-2 layers of 4mm soric.

100C cures for the pre preg parts.

I had one hand laminated mould 500x500x200mm sandwich design, but core was based on epoxy foam. Stiffness was great. It works ok, however only for OOA prepregs. In autoclave the mould was destroyed totaly by overpressure.