Buy a sheet of 1/8" 6061 6"x48" alum. off ebay from "Speedy Metals" for $14, and you're set. Cut a section with a hack saw or whatever saw you have, put it in a vise, and beat the snot out of it to get it in a 90* angle.....AGAINST the grain of the metal, of course. I'm pretty sure that's how my brother did it, that's how I did it for my Twin Force's motor mount.