I need some help with an issue

Treblig said
Two part grey epoxy would seal it up for good as far as making it usable??/ There isn't anything but a slight vacuum in there anyway.

I didn’t want to risk epoxy and even bought copper to use for a back up and put a goodie weld on it. But I’m just trying to get some more opinions. After he explained it to me it makes sense to me that it can’t harm anything