Do I use concrete? Sand? What else for "locking" down some stones on walkway?

[Yoyodyne ArtWorks]

fromish wrote:
There is a special sand called polymeric sand (Home Depot, Lowes) that stabilizes pavers and prevents weeds and insects from causing problems with the sand. It's not as cheap as playground sand, but it lasts in my experience with paths and patios made of pavers.

I thought of that too, but wonder if it's effective when the gap between the stones is that large. We use it on our patio and it works great, but the gap between pavers is less than 1/4th of an inch.