For many years, when we got a pair of boots or waders that did not have felt soles, we would grind off the lugs to create a flat surface then glue on the felt. Got a new pair of waders a couple of months ago and proceeded to grind off the lugs. Much to my surprise (and dismay) the lugs were not molded rubber as usual but rather an open-cell foam with a thin layer of rubber encapsulating the surface. When I broke through this skin the boot foot was no longer waterproof. So I returned the waders to Cabelas taking responsibility for altering their product but also informing them that this was a radical departure in boot construction and not a very sound way of making the bootfoot. What's going to happen when that thin rubber coating wears away? They were very understanding and replaced the waders. But how to apply the felt soles? Simple solution. Place strips of felt or rubber between the lugs to create the flat surface. Glue the felt to the flat bottom and insert sheet metal screws. Hope this saves some of you from experiencing the problem I encountered.