Waffle chips, called gaufrettes in France, are easiest to make using a mandoline equipped with a ruffled blade.
3 lbs. Idaho potatoes, peeled
1. Using a ruffled blade in the lower plate of a mandoline, cut potato, creating a ridged surface. Twist potato 90 degrees, then slice against the grain through the potato. Discard the end slice, adjust the height of the lower plate (if necessary) to slice potatoes about 1/16" thick, then continue rotating and slicing potatoes until all have been sliced. Place waffle chips in a large nonreactive bowl and cover with water.