It sticks forever. Until you peel it off! It really is amazing stuff.
What a clever use for the cans- I like how the colors of the can play against each other nicely. But, my first thought was, “Better keep the bandages handy!” Could you add a bead of solder around the edge? I’ve never used it, so I don’t know if it would work in this situation, however.
Good idea! I will have to look into that. I have a soldering iron somewhere around here… as well as a little butane torch. Will experiment a bit when the weather is decent.