I have a small fire-proof locking document chest that I would like to take in my carry-on. It is small enough to fit in my roll-aboard.

Has anyone had any experience bringing these through security in the US? Also, my destination is the PRC, so would this cause any issues with customs?

I plan to bring the keys with me in case they need it to be opened, but I'm more concerned with the thickness of the chest exterior and if the X-ray can distinguish that there is nothing hidden inside the walls of the chest.

I emailed the TSA contact address several days ago, and still have not received a response.