the vacum system is simulating a very large weight on the construction. That I can do too by putting a table upside down over the foam and loads of weight on top of that.
Actually, to simulate the vacuum's 'weight' you would need to have a large car (not just a SAAB) on top of the parts being joined, and have to ensure that all sides of the parts (shucks) were being held together by the exact same weight - as a vacuum produces. Didn't you look at the video? Jim uses - very successfully - a $50 food saver vacuum system.