1) Slice the potatoes about 0.1cm thick with a mandolin-style vegetable slicer. Put the slices in tepid water, to cover, and soak for 30 minutes.
2) Fill a tall heavy-bottomed pot, like a stockpot, about a third full with the oil. (Don't over fill the pot with oil, since it bubbles up during frying.) Set a deep frying thermometer in the pot and heat the oil, over medium heat, to 185C.
3) Drain and spin the potatoes dry in a salad spinner. Spread the potatoes out and pat them dry with paper towels. When ready to fry, raise the heat to high. Working in small batches, carefully add the potatoes to the hot oil and fry until golden brown, about 2 to 2 1/2 minutes. Lift the chips from the oil with a slotted spoon and transfer to a paper-towel covered baking tray to drain. Season with the salt. Repeat with the remaining potatoes, taking care that the oil returns to 185C. before adding each batch. Serve warm or at room temperature.