I personally prefer cotanger material for the early 172 hinges.

Cut it about 1" longer than the hinge, bend the top ½" over at about a 10°
angle, insert it into the hinge, and then bend the bottom ½° at the same angle

Jim
Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com