3m makes some pretty serious VHB tapes.
Call and ask for a sample, I got one years ago for a project, and still have a bunch of it.
The "Sample" was pretty big.
That project involved taping down Aluminum Hershey Kisses type things to a snowboard, and they are still there 8 years later.
Experimenting with the stuff they sent me showed that the board delaminated before the tape gave out.
The couple I managed to pop off still have snowboard on them.
Still don't think I'd use it on a knife though...