Step 1: Pole options.
Alternatively you could use a walking pole as these often come apart by themselves. If you then place the mount behind the plastic join then you can keep using the pole as a walking pole and a go pro mount.
The benefit of using these poles are that they are robust, designed for extreme conditions and already have a grip and leash (handy so you don't lose your expensive camera).
But if you want to use something simpler then try using a length of PVC pipe or wooden dowel. You could add you own sugru grip to the end.