Welding rods, 7018 is a low hydrogen high strength rod and easy to get a good weld with, but Only if dry and kept in a heated oven. Without being dry it picks up moisture and is no longer considered low hydrogen and can develop cracks like a normal weld. 6010/11 rods are used for deep penetration and general purpose welding and can be used on dirty or somewhat rusted metal. The 60 series rods do not need to be kept in a oven.