Hello, A couple of questions...

Hi Gandude. Just went through this myself. What RRR said, 3M#8308 seam sealer. I also live in 94518. You can pick it up at Finishmasters on Willow Pass Rd. Near Safeway, or Ned's on Market St. next to Ace Motorcycles by Concord BMW.
Treat the metal with phosphoric acid. Directions say to wash off and dry, then ok to paint. I used etching primer first, then primer, then paint. I figured the floor will outlast me, since I just turned 60! Would like to see your project sometime, Private Message me if you'd like to meet.