I just set up a 2nd base, but it kinda tedious to jump between both bases to grab building material, so i wonder if there is anyway to share resources between your own base?

From Steams discussions.

There is not.

For now, take advantage of the grappling gun to be able to move when encumbered. e.g. build box within grapple range of the Palbox of the base with surplus resources; load up the box; pick up the contents, grapple to the fast-travel point despite being encumbered, fast-travel to the destination, grapple to a box on the other side, drop off the stuff. There's no automated solution.

- https://steamcommunity.com/app/1623730/discussions/0/4203615689063242470/

With that said. Some say that building materials such as wood, stone and other materials Are shared. Either way, using the quick travel is probably your best bet to move resources you need.