Leather film or barrier

[friquant]

As kgg mentioned, I've tried stitching with a sheet of copy paper under difficult materials. This made the stitching easier, but I had trouble removing all the bits of paper afterward. Perhaps something thinner that would dissolve in the water like tissue paper (the kind people wrap gifts in) or aluminum foil or wax paper or mineral oil or flour and water or cornmeal (ew!) or any of your favorite spices from the kitchen cabinet. Spitballing here, have not tried any of these 🙃

[fredk]

afair there is type of hemming or binder tape that is water-soluble. Meant for dress makers to hold a hem whilst sewing then it dissolves in the wash. Could something like this be used?