I like that vaccum approach... for the pressure side of things... bear in mind... 1 PSi is 144 lbs per sq foot. We test ship welded seems... we put in 2 psi... sometimes I hear welds breaking loose.

fiberglass will explode. 1 psi would be plenty to make bubbles. Also note that if the air flow is too strong... it will blow too hard to make bubbles. You should be able to hear it though