Zippers tend to fail in various different ways, most often when the little handle breaks off. However, with respect to the particular zipper that inspired this Idea, the part that zips the teeth together (usually known as the "slider") broke. All the zipper teeth, on separate toothy strips, are still in good shape; I just need a new slider.
So, fire up the 3D printer. Print two separate pieces that can be snapped together to form a new slider --one of the pieces would include the handle, of course. Just be sure one of the toothy strips is enclosed, when you do the snapping-together of the two parts --zippers always have the slider "permanently" engaged on one of the toothy strips. (Hah! If it had really been permanent, my slider wouldn't have broken!) Since we don't want our new slider to un-snap, the design should be one-way-only, for snapping together. That's all.-- Vernon, Nov 25 2016 Here's an alternative http://homegear.com...ic-metal-nylon.htmlThis two-part fix has a screw holding the parts together. [Vernon, Nov 25 2016] Zippity_20Undo [xenzag, Nov 25 2016] Prior art: non-snap-on 3D printed zipper slider http://www.thingiverse.com/thing:259899 [notexactly, Dec 18 2016] fine with me-- beanangel, Nov 28 2016 random, halfbakery