The top of the JB weld lid on the outside has a pointy thingy on it used to pop the foil, no need for a pointy thing, rule of thumb for anything with foil sealed things like that.
You will have a hard time making things stick, because the casting needs to be very clean. As well as the surfaces, remember that most aluminum castings are rather porous so you need to do a really thorough job cleaning the edges of the hole. I recently did a similar repair, and I had to soak the case in a strong PineSol solution for a couple days, and scrub it down with a brush. It's a good idea to go over the patch area with steel wool before applying the JB Weld.
It’s sticky enough to hold itself on there. Maybe apply it a few times. There’s plenty of solution there for you to get dirty with. But mhmm now maybe you could get cardboard and do it the reverse way I did it. Put the solution on top of the cardboard and pry it good enough to where there can be no slip. I hope that make sense 🤝
