Fuel tank fasteners

This invention relates to an integral fuel tank fastener, and more particularly to a method of blow molding a plastic fuel tank having a unitary fastener feature for engaging a clip of the fastener. An integral fuel tank fastener having a unitary fastener feature or hollow protuberance carried by and formed into a preferably blow molded multi-layer plastic fuel tank shell. The fuel tank shell preferably has a continuous intermediate layer, or permeation barrier, between continuous inner and outer layers in which the protuberance is formed without producing any discontinuities that could degrade the permeation integrity of the fuel tank. The hollow protuberance projects into a fuel chamber defined by the inner layer and has an enlarged head at its distal end. The outer layer defines a blind cavity of the hollow protuberance which substantially follows the contours of the opposite side. A female clip, independent of the fuel tank, preferably engages the protuberance about the inner layer of the shell.