Tue Dec 15, 2009 8:44 pm
When a carboy is full, there is a lot of outward pressure being exerted on the glass. A while back, I was setting a full carboy of sanitizer on a concrete floor, which was completely smooth. The carboy crumbled when I set it down. After cleanup, I investigated and found that there was a tiny piece of aggregate sticking above the finished surface of concrete. Basically, the top of a BB-sized rock was exposed, probably a mm above the finished surface. This is a different scenario that the flask to the top of the carboy, but it does illustrate their wimpiness.