I have bee curious about this, can some one please explain how air does not get trapped in between the rubber in this process. There is certainly some air pockets when you pack the mold, and then the clamping certainly seems like it would seal that air in between the layers. So with out any vacum how does all the air get out? Not having tried this I am amazed that it all would just squeeze out every tiny last bubbel? How does it work?