Some things just cannot be found at your local hardware store unfortunately.

If you plan on doing more than 1 build suggest buying 2 micro mesh 'guitar' packs as on my 4th the 4,000 grit was already knackered from the 3 previous builds but stepping from 2,000 to 6,000 was not a problem as that still had plenty of bite even up to 8,000 grit. At 12,000 it takes things to an insanely smooth flat level finish with no lumps or bumps.