Plutonium doesn't explode on itself. Unless you pack it into the complicated mechanism of a nuclear bomb device. Other than that you can do what you want, wrapping it in explosives and firing them will just disperse the plutonium but it will not make a chain reaction.
My layman’s understand is you need a neutron trigger to destabilize it rapidly, as well as a shell to contain it to get a stable chain reaction going. I think you typically need to be at the center of a an exploding star to see that happen just from pressure.
