I was a gen. enginering contractor for around 25 years specializing in swimming pool's and decorative concrete, now i work night's in facility maintenance for the county, guess I'm a turd herder in a way, just a little closer to the finished product than you wwt guy's, also do maint. on some rentals, used to ride saddle bronc horses and bull's, taught Kenpo and Tae Quan Do for several years too. all i know is with two art. knees buy 48 yrs old i needed to get into something a little easyer on the body, Bub