Best Plastic Sealant

i am using 55gal plastic drums cut in half. i am having a problem with the "upper" half leaking around the two screw in caps. I have used pipe cleaner and glue with no luck. i was thinking of aquarium glue.

any suggestions.

Can you provide a picture please? I'm having troubles picturing your screw in caps....I ask because the answer to your question is dependent on your situation. (Is it going to be under water constantly or just splashed occasionally? What types of plastic? What sort of water pressure do you have to fight?)

I use GE Silcone in a caulk gun, any home depot will have it. I seal my fence posts with it and glue the end caps on. It holds well and you can cut it off and sand it down if necessary.

I've used aquarium glue before to seal holes for tubing ports on the bottom of my DWC units. I probably wouldn't do it again, I've had leaks...instead I use decent bulk heads and that silcone.

pics pics but whatever you use make sure it food grade safe

those bungs are supposed to have gaskets.(o-ring)