Vacuum Bagging is a great approach to surfboard building. The end result is lamination layers that are well incorporated, with a near-optimal resin to fiber ratio, pressed hard against the foam to resist delamination and increase the surface bond. It also ensures the shape contours are faithfully followed by the glass or carbon.
The traditional process is to do one surface at a time–mostly because traditional wet layup methods require that. If you flip the board over before the epoxy hardens, the glass or carbon can drop away from the blank, or the wet glass just gets disturbed by the stand. the end result is a mess.
But with bagging the force holding the laminations against the blank comes from air pressure, not gravity. Glassing (or maybe we should call it “carboning”) the entire board has big advantages since the top and bottom layers can chemically bond instead of just mechanically stick together. the end result is a stronger, lighter board.
Of course, doing both sides and placing any reinforcements or features that are covered by the glass takes planning and a bit of choreography. It’s not something beginning glassers should undertake. Fortunately, the SIC by JungleWRX crew knows how to do this dance. Enjoy the video.