u/Sufficient-Tangelo-7

So I’ve kept my pit barrel fairly clean. I’ve stored it outside with a cover and would empty the ash the next morning after it had cooled down. Over time it developed some very small rust holes and I patched those with JB Weld. Well after first cook of the year I went to empty the ash and a giant fist sized hole appeared. Only option is to replace the entire bottom or weld a plate to it. I think I might just buy a new Pit instead. Any suggestions on preventing this rust from happening?