When I was 12, I spotted a bundle of 3/16 inch dia copper tubes my Dad brought home from the worksite junk pile. They would make a cool frame for the .049 powered slot racer I had been planning. My Grandad had shown me how to solder copper so I fluxed a couple of the tubes and set the torch to them. They were on the concrete floor in the garage, it was wet, the torch was hot, and a 2 inch diameter piece of concrete exploded and stuck itself to my cheek. As I jumped back, trying to unstick the hot concrete, the torch wound up under Dad's hardwood lumber rack in the corner. The neighbour put out the fire with our garden hose. I was 17 before I was allowed in the garage unescorted and from that day ( Dad's 85 I'm 61 ) he always had a 5 gal pail of water, wet towels and an extinguisher handy when I plumbed houses with him. The one time he needed those things for the wall cavity fire, he'd gone out to his truck, so I had to call the fire dept. I still can't get him to smile over that one.