I like kevlar because
- its a very tough material as you are scoring through to it. Sometimes, (depending on the actual application), as you cut through the outer wing skin material to contact the cloth hinge material, you can accidentally sliced through 'other' cloths even with TLC. Once its cut, it is no longer a hinge & kind of hard to repair. You can have the same situation with kevlar if not careful, but it is actually quite forgiving that way because teh fibers are so tough. Once scored, give the flying surface a crack to relieve itself of the epoxy & it has become a nice, slop free hinge
- its available in a few useful weights. I personally favour 2.2 oz
- depending on the source, it is avaliable in tape form too which can save you a bit of time cutting long ribbons. Although technically it should be layed on the hinge-line at a bias so you have more 'crossing' fibers, Ive layed it at a shallow angle & never had any issues. Once upon a time I heard Dacron ?sp? was sold in tape form through boat shops. Might be a good option too.
- in the permanent non-moving hinge, ie the cloth material fore & aft of the hinge line, kevlar then serves as a good structural material
- although I havent personally experienced it, some of the nylons & peel plys have been known to loosen up over time. This could be related to how it was bagged, any kind of release coating on it, or high deflection surfaces like flaps.