I like to use mesh fabric for my waist belts. It is light, breathes well and has some degree of grip due to the fabric construction.
I've made several waist belts from military surplus hat stiffeners which are made from saran mesh. They worked well. Saran mesh is not readily available, however. I've tried several substitutes and here are my impressions of them fyi.
Acceptable Meshes
Leno Loc Mesh-Very little stretch in length or width. Does stretch on diagonal. Weighs about 7.6 ounces per square yard. Nylon. About half the weight and half the thickness of the military surplus saran mesh. This is the one I would recommend but I only have about 10 hours of use on the belt made from it so time will tell.
Polyvynal Mesh-Very little stretch in length and width. Does stretch on diagonal. Weighs about 10 ounces per square yard. Coating on internal threads started to wear off after a couple hundred hours of wear.
Not Acceptable Meshes
PB81 Polyester Mesh from Carr Fabric-Stretches in all directions. Weighs about 3 ounces per square yard.
80% Knitted Polyethylene Shade Cloth-Stretches in all directions. Very lightweight.
80% Woven Polypro Shade Cloth-Didn't buy any but website says it unravels if it gets a hole in it.

