Q: Why does a suitcase zipper split at the corner?
Corners concentrate stress and are where the tape is most often distorted during making-up. A split that starts at a corner usually starts in the seam, so inspect the corner geometry before replacing the slider.
- Mark the exact start point of the split and photograph the corner inside and out.
- Check the seam allowance and whether the tape was trimmed close to the chain.
- Look for a sharp fold or a stretched tape at the radius.
- Check the slider as it passes the corner: does it ride up or catch?
- Compare a corner sample made with a larger radius or a relieved seam.
A corner that splits with an intact slider and chain is a making-up issue and is fixed by seam design and tape handling. A corner that splits with a spread slider is a zipper issue. The repair should address the corner geometry, not only replace the slider, or the new part will fail in the same place.