Thanks. Isn't the bike tape slightly padded?

I'll try the shipping tape first. I'm glad I took the box apart to check it out. I told the owner I fixed two things on the box while I was looking at it.

She wondered if she could just rotate all of her boxes through me, so I can gradually get them all in good repair.

Cloth bicycle tape is not padded.

Inside my GGFs 1880 2 1/2 row D/G is a section of a playing card .. cut to a strip about 1" wide and creased then glued over the worn/torn fold... very cool.

Gaffers tape might be a good choice. It is quite strong, like duct tape, but it doesn't leave a gunky mess like duct tape does if you try to remove it.

I have used gaffers tape for internal attaching and sealing of different things.