If I create a partion on my 32gig USB stick using rpi2 then format it to FAT32 allow me to then copy the SD card of the Rpi2 onto the USB stick?
You could copy all the files, BUT would lose all file attributes, including symlinks and hardlinks, as well as permissions.
It is feasible to copy your home directory, but the system files, while present would not work, and would not allow you to restore a working system.
If you formatted to
ext4 you could copy the root directory, but this would still not give a working backup.