10-01-2019, 09:38 PM
(This post was last modified: 11-01-2019, 09:22 AM by cardiffrob.)
"Sharpie" pens are good for annealing since the ink disappears at the right temperature. Cheapo 1050 grade ali doesn't really work harden and stays soft enough to work. 3003 grade is semi-hard and hardens when worked whilst 5251 is bloomin' hard until annealed. I'd save the 5251 for flat panels since it is a bit too much for forming, although does make lovely smooth finishes.