I buy the material for making my cloth hinges from Aircraft Spruce. What I buy is the light weight Dacron. They use this material to cover ultra light aircraft. You buy it by the yard and a yard is a lifetime supply and it does not cost much at all.
The only aggravation that I ran into was that it wants to fray on the edges. What I discovered was that if you dope the material first, when you cut it, it does not fray. The material comes folded so what I do is cut a strip while it is folded about 2" wide. That gives you a good long strip to work with. I then unfold that strip, lay it out flat and dope it with Nitrate dope by brushing the dope on and saturating the cloth and it only takes a few minutes to completely dry. I then lay the strip out and cut the desired length of hinge I want on my cutting mat using a straight edge and store them in a container or apply to the stab or flaps if I am ready to use them. I find that a sharp #11 blade and a straight edge (ruler) is much better than using scissors.
If you use cloth hinges you might already know this but thought I would put it out there for those who maybe did not. Hope this helps
Mike