Aluminium tape, as used for airducts etc.
It's thin enough to pass as in-scale tape, and strong enough to stand being cut into thin strips. And since it's adhesive on its own, you can apply it in a realistic fashion too.
Just make sure to cut it into strips before you remove the backing paper, as it's quite sticky and the material might snap/tear.
I've used it for a variety of different purposes, and it's a great hobby material!