Fold Wall-Sanding Sheets So Rough Locks Against Smooth

The Problem

Sanding a skim-coated wall burns through sandpaper, and a sheet folded casually in half fights you the whole time: grit rubbing grit dulls both faces, and the loose layers slide against each other instead of staying put in your hand.

The Technique

A painter's version of the classic fold:

1. Fold the sheet square — in half, and in half again — to crease it into quarters.
2. Slice along one fold to the center with a putty knife (his 4-inch knife doubles as the cutter).
3. Fold the panels over each other so a grit face always lands against a smooth paper back. The rough face bites into the smooth one, so the folded pad holds itself together and doesn't creep while you sand.
4. Sand with the exposed face; refold as each face loads up or dulls — four working faces per sheet.