I had a carpenter make me wooden frames to a specified size and attached the mesh using heavy duty industrial staples along the 4 sides of the frame. it is quite easy to stretch the mesh once you have attached it to one side and because the staples are along the side there is no chance of any contamination to the print. I have an area under a bench in my darkroom where I have mounted the frames on drawer runners so that they slide in and out for loading.