Originally Posted by Hutch
Are those to help separate the mold halves once everything inside is all cured up?
That's the idea Hutch - I had the o-rings under the bench and the fittings cost me under $10 in total. Each of them will be pushing down on a wooden insert cast into the lower half. It might work, it might blow the inserts out of the lower section, it might crack the lower cavity, it might do all of the above to the upper tool, and it may just look silly in the end, but l'm gonna find out - slowly as I turn up the pressure mind you...
I opted for the barbed fittings so that it's easy to configure with 1/2" hard vacuum hose. With a pneumatic control valve, and an actuator it might be possible to alternately apply vacuum to help with mould assembly after trimming and prior to joining or alternately positive air pressure to open the mold post cure.