I've never made a keyblade from frp, I'm sure it's possible, but I found it much more easier to make it from plywood. You just need a jig-saw, if you don't know how to use one you should ask a neighbour or I guess parent if you still live with them, or get an extra piece of plywood to practice on and wear goggles. I blew up the image of the Oblivion and Oathkeeper to life-size proportion, drew it out on a big sheet of paper and traced it on the wood using graphite paper. It doesn't take long to jigsaw it either, depending on how detailed it is, I cut mine out both in a day. When it's cut you want sandpaper to round it out, which can be time consuming, but it looks so nice afterwards :3 What kind of paint you use is up to you, I have a bunch of different spray paints so that's what I used and then went over it with a gloss. I hope I helped, I think a wood-made keyblade is much more sturdy, but heavier might I add lol. Good luck!
Ninetails - OG Pokemon heh