Ok I see the tougue on the lid. Am I right that I do not see that toungue on the back of the lid? If not, you may need some extra tape there to build up and make sure ther is not a leak. Usually where t pieces of just sit on top of each other, there is not a great seal there. I would use several pieces of tape to build it up all the way around, so that the tape is thicker. Also I would only build up one side, and just that toungue no need to put the tape on both sides. But youve got the idea, now its just getting it built up enough to seal it off.