The trade of plumbing originates from the Latin and chemical symbol for lead. There can't be many on here that have ever wiped a joint with moleskin. I was apprenticed as a coppersmith, my first test piece was to make a ball float from scratch, soft soldering the seams with irons. we made scotch joints and saddles from 2 " copper filled with resin, bent with 6' iron bars with the pipe chocked on a slab with wooden wedges. I learnt silver soldering and brazing, and in my trade test I manufactured a complicated 2" pipe between flanges to a tolerance that allowed only one test fitting. I served as a Royal Naval Artificer, and subsequently worked for 10 years in building services, I ply my trade in property maintenance now, and accept work involving plumbing, but never call myself a plumber, because I didn't serve the time. You earn the right to call yourself a plumber, you earn the right, and pay for it to become GSR. Engineer is a professional title and usually is bestowed upon those who have qualified to become members of an institution (mine was I Plant E until I lapsed it). Being multi skilled is not a crime as long as one does not profess to be that which he isn't