Could you make waterproof glue by just adding gelatin to pva glue?
PVA glue is “permanent white glue.” It comes in various brands and qualities, all of which are waterproof (actually water-resistant) after they’re dry. If the finished coated items are *soaked* for a while in water though, they’ll soften and may separate. Are you making these origami things from paper, fabric, or what? Do you need them to be rigid or flexible? How water”proof” do they need to be? PVA glues could work depending on the answers to those questions but wouldn’t be stiff on any of the materials that weren’t already stiff. Clear polyurethanes would be a bit stiffer and more waterproof even with soaking; epoxy resins (2-part) would be more hassle but would be stiffer and waterproof, though both could crack if thin and bent. Again, depending on the material you’re making the straps from, you could encase them in other kinds of materials which would be waterproof (and clear if you wanted) –things like iron-on plastic sheetings from the fabric store, clear self-adhesive tapes an
