The whole point of using the aluminum tape is the almost mirroring surface. The big issue here is that ANY uneven nanometer of the blade will be 100 times as visible with a surface like that. Not to mention that aluminum tape is fragile and any dent will be VERY visible too.
Hence why I consider painting over aluminum tape to be a waste of time. As you need a smooth surface below it already, just cover it with a little gesso/bondo instead and sand it down all nice and smooth then paint it. Much smoother and better result and gesso is not exactly expensive stuff either.
Completed cosplays: Vincent Hitachiin Hikaru
Plans: Syaoran (casual), Nero & Kaito
Planned cons: Next Uppcon & Meuwcon