Dec 01, 2003 · HDPE is naturally a translucent white lor. Red pigment has been added to this welding rod to get a better match when welding red HDPE pieces. This package ntains 30 ft. (9.1 m) of high density polyethylene (HDPE) plastic welding rod. Each rod is 12 inches (30 cm) long and 1/8th inch in diameter and there are 30 rods in the pack.