The first step after the joints are wrapped in prepreg is to cover each joint in release cloth. In this case I use a very fine woven coated nylon that lets excess resin through during cure.
Once all the joints are covered they get a layer of bleeder/breather material to distribute the vacuum across the joints and absorb excess epoxy. Once that's in place the frame is slipped in a vacuum bag. I use Stretchlon 800 which is a 500% stretchable material that can withstand cure at 250F. You can sort of see how I form a "Y" shaped bag to slip the rear stays into. I actually managed to bag and pull a vacuum with no leaks which is a border line miracle!
Here is Chuck's frame hanging in the oven post cure. You can see the epoxy saturated cloth at the joints. I added a support bracket and bearing to the oven fan so it didn't try to self destruct this time.
Some quick work with a file results in this. I just take off the little ridges and high spots. You don't want to be removing carbon.
Post cure weight is about 26g less than before the oven. That means quite a bit of epoxy was removed. The prepreg I use is 45% resin to start. The cure process brings that down significantly.