Thanks Mark.
I had the same thought about keeping the vac pump on after the infusion i.e. sucking the resin out. I guess it depends on whether its possible to drop it to a token amount.

Its quite hot where I live, with temps in the high 20s and 30s. The epoxy cure time is  around 24 hours, with de-moulding possible after about 10. The humidity on the east coast where I am is frequently above 70% (meant to hit 87 tomorrow) which makes me think it could be a boiling issue. I'm about to add a cable gland to the middle of the chamber so it can be set up with the suction line directly in the resin pot clamped off. Then it can pull a vac to degas, crack the pot through the ball valve under the vapour filter, and switch the pump across with a single hose to keep the process going without stuffing around too much. I've had all 4 of my infusion attempts fail in the same way, with small incremental changes each time. Its frustrating but am willing to try just about anything to get it right at this point.

In terms of leaks, I'm fairly confident the bag was ok. I do a drop test each time and leave the dry stack on vacuum for about an hour, and already do the press down thing around the tape as the resin flow starts. 

From here I'll add a resin break and include the degas section and see where it ends up. I might also drop the vacuum to see if that makes a difference.