Yes, labels from the Brother PT-70BM will adhere to the surface of a hard hat.
#2 Do the labels peel off easily, say once you're finished with your leftovers and are going to re-use the container?
If it is a butter container or cottage cheese container, the markings on the container will come off with the label. Tupperware the label just peels off. But the label usually comes off pretty easy.
#3 Do I need to buy ink for this? or is it thermal?
To make two line labels with the Brother PT-70BM labelmaker, move the cursor where the second line starts and press the Enter key. For more information, feel free to contact Brother Customer Service directly.
#6 Does anyone know how to change the margins on the printer? I'm trying to avoid all the wasted space on each sides of the words I print!
No. I just advance it enough to print short strips.