Portable pvc air tank for pneumatic cannons?

I, after 2 years, managed to convince my dad to let me make a pneumatic cannon. The only problem is, I can't use his giant air compressor, but I can use a portable air tank. I don't have one, but was wondering if I could use 6 or 8 1'6" long tubes of 2-3" pvc pipe in junction to make a good enough air tank for maybe 3 or 4 good shots. I could use a little 12 volt air pump to pump it up using a schrader valve. Would this work well? The intended projectile is a tennis ball and the planned air cannon uses a piston valve.