Currently I'm undertaking my first CF project, which involves manufacturing a 'closed' shell from CF. My skills, knowledge, and equipment are relatively basic so I'm making two sides of the shell via resin infusion and a Unimould system mould, then I will join them to get my 'closed shell' 

You can try using expanding silicone for the same effect. The heat expansion of silicone can be used to apply pressure to the mould surface in the same way a bladder is used.  Obviously it requires an elevated temperature cure and as such is best suited to pre-preg use.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant