Originally Posted by
frets24
Scribe the circle using a circle template and a good sharp pencil then cut out with scissors. Look at it from the backside after to see where it might need to be trimmed or shaped up...easier to eyeball the shape without the glare.
I do that, too.
I've also sharpened cut off pieces of wing tubes. Place the sharpened end on the aluminum and smack the other end with a hammer. It's a poor man's die cutter. LOL
You can see one on the fuselage of my Stuka, just below the elevator control horn, in the attached pic.