I'm curious. I know how to make flat sheet membranes but hollow fiber and one inch I have never tried to make. Just looking for helpful advise before I start.
Tubular membranes for microfiltration or ultrafiltration are made by creating a substrate of permeable material (ceramic or plastic) then casting the membrane (made of a similar material) to the surface of the substrate. The membrane is usually a few microns thick. The casting process and exactly how the porosity is achieved is usually proprietary.