[abl1111]

I always wanted to try something:

Clean the that lip well w/ acetone, sand it nice and flat, clean again, then add a uniform 1/2" high x 1/2" wide bead of very durable silicone, and while still wet, place a flat wood 'jig' over all (4) sides of the lip - almost like a 'long paint stick' ( the bottom of this thin wood jig would have wax paper on it ). Then, press very this lightly to get a uniform flatness - not smooshed flat! - let it dry. Then remove the waxpaper/wood and that would be a built in gasket ?

Does this sound like it would work ?