It's not a false nail that I use. It's a layer of acrylic put on top of the existing nail. The acrylic is a white powder in a little jar. It is applied by a brush that is dipped into a clear chemical liquid (acetone?). This turns the acrylic powder briefly into a gloppy clear viscous semi-liquid that is quickly spread on the nail, using the brush. It is spread out in a even layer, about a millimeter thick, on top of the entire nail. It begins to harden within less than 30 seconds, and sets up in about a minute, I'd say. It is then sanded and filed lightly to the final shape.

What you have then is a heavily armoured nail that is virtually unbreakable under normal circumstances, and works great to play the guitar.