Separating them is tough. First, drill out the rivet heads and poke them and their casings inward... then heat the aluminum hot enough to bake the adhesive joining the comptip to the mast to release its bond.
I used a Harbor Freight heat gun and 10-15 minutes. It helps to have the mastbase anchored to something immovable (house, car, tree, etc.) and then exert some pull on the comptip to something equally immovable. I used the mainsheet gear to create tension/load, and had a sawhorse/prop ready to catch both ends when they release.
Good link here:
https://www.hobie.com/forums/viewtopic.php?f=15&t=21589Randii