On the inside surface, in the valve area, we placed a disc-shaped piece of fiberglass cloth, as reinforcement. A 2.5" opening is later cut inside the reinforced area, for acess to the valve
Man that is just too cool !! Thanks for posting that one..always wanted to add some type of a "Moon Disc' to my rat...that is MUCH easier and nicer than what I was coming up with !! Time to get busy !!