*I am assuming this is the same drum from your other thread.
*Also assuming this is a closed head container.
Just a thought...
*Cut off the top 3-4" down.
*Make a two 2" strip of FDA rubber as long as the circumference of the barrel.
*Take one strip, make a ring and fix it to barrel where you just cut. 1" inside, 1" sticking out the top.
*When you put the lid on, take the second strip and wrap it around the seam.
*Fix it in place with cargo straps
like I said, just a thought.