Here is a mod I did for Thundertron's sword (and a different 'perch' for the parrot). NO PAINT REQUIRED. I've seen alot of mods for this but none i was happy with.
1 thundertron sword
1 silly straw from walmart
1 tail of HFTD Tomahawk's missle
drill with a really small bit
First i disassembled the sword completely and took the electronics box-gimmick parts out. Then I put the sword part and the translucent 5mm peg part back together and dremeled out the bottom, enough so he could fit his hand in (tip: put a screw back in to keep then together while dremeling!). Then for the handle, I glued the missile tail into a long piece of the silly straw i cut off with the xacto. then I drilled a tiny hole in the top, just big enough for one of the smaller screws left over from the electronic disassembly (the one that fits into that little hole on the top of peg piece (not on the peg itself) - it sits under that little half circle thingy on the claw part of the sword. Then I just pushed the handle onto the little screw on the hilt. after a little super glue to tighten up the blade joint, it was finished! Transforming sword with knuckle spikes!!
For the parrot 'perch' I just used a curved piece of the silly straw
Sword at side: