Troubleshooting Issues with Tin Capsules
Last updated: 6/2021
Applies to: Winemakers bottling with tin capsules and encountering wrinkling, cutting, folding and other problems.
Common Problems and Fixes
Below our Cork & Packaging experts have curated a short-list of commonly asked questions from our tin capsule customers, as well as a few pro tips on how to select the right capsules, and what additional tools and products are useful to have on hand:
Wrinkling on spin down
- Check and confirm the bottle provided to supplier is the same mold. Changing suppliers that have the same mold can vary enough to create wrinkling.
- Confirm that the bottle is centered and that the cap is being applied with an even amount of material on all sides of the bottle neck.
Cutting under the bead of the bottle
- Reduce the tension on the spinning head. You may also need to replace the sharp rollers with more blunt rollers. Typical head roller set-up is 3 sharps and 3 blunts.
- You may need a heavier/thicker micron due to a large bead. Verify that the bead is in specification and does not have too sharp of a radius.
- Special "shouldered rollers" are available to help with this glass defect.
Small fold over at the bottom of the capsule on the skirt
- Reduce the tension on the head.
- Check roller wear. Rollers with a flattened radius will have more drag on the capsule, stretching it and causing a small wrinkle at the bottom.
- Check that the bottle is going straight up into the head and not to one side. This will push more material to one side as it is being spun down, creating a wrinkle from the excess material, i.e. a fold over.
- Bottles with very straight necks (little taper) are more prone to fold overs, therefore proper fit and micron thickness are critical.
Sliver tin is showing through under the bead when spun down
- This most commonly occurs on big bead bottles and is caused by the capsule being stretched too far under the bead, exposing the raw tin underneath.
- Typically more pronounced on darker colored capsules.
- Reduce the tension on the heads and fin a happy medium.
A note on Rollers
If your capsule has been sized with the correct micron most of these issues can be reduced or eliminated by reducing the tension or changing to new rollers with less wear. It takes time to replace all the rollers and it’s best to replace them on one head and see if it makes a difference. If you have a mobile bottler, ask them to do the same and change one head with new rollers to help reduce or eliminate issues that you may be experiencing. If you have your own bottling line, it is always best to carry a spare set of rollers on the shelf.