Manufacturer · Fashion & Home Accessories
A hidden zip is a spiral zip with the coil turned to the inside of the tape. Once sewn in, the coil disappears into the seam, leaving only the pull visible on the outside. A regular zip – spiral, metal, or moulded – has teeth on the front side and remains visible or is covered with a flap. Hidden zips suit dresses, skirts, and elegant garments, while regular zips are better for heavy-duty and visible closures.
How a hidden zip is constructed
Both hidden and regular spiral zips have a continuous nylon coil sewn onto a textile tape. The difference lies in the direction: the hidden zip’s coil is “wound” towards the back side of the tape. When closed and sewn in, the two tapes meet closely, forming a narrow seam with the coil underneath. The slider is also on the inside, with only its thin “foot” and pull visible outside.
Differences between hidden and regular zips
| Criterion | Hidden Zip | Regular Spiral Zip | Metal / Moulded Zip |
|---|---|---|---|
| Visibility | Invisible, only pull visible | Visible or under flap | Visible, often decorative |
| Typical size | No. 3 (sometimes No. 2 or 5) | No. 3–10 | No. 3–10 |
| Flexibility | Very flexible, lightweight | Flexible | Stiffer and heavier |
| Load capacity | Light to medium | Medium to high | High |
| Construction | Usually non-separable | Non-separable, separable, two-way | Non-separable, separable, two-way |
| Sewing method | With special hidden zip foot, before seam | With regular zip foot | With regular zip foot |
| Typical use | Dresses, skirts, trousers, cushions | Trousers, jackets, bags, sportswear | Jeans, jackets, bags, leather goods |
When to choose a hidden zip
- When garment lines are key – evening and formal dresses, skirts, blazers, trousers with a clean front.
- For delicate fabrics – silk, chiffon, satin, jersey, where a heavy zip would pull the fabric.
- For fitted designs – the thin zip avoids a stiff edge and follows the body’s shape.
- For cushion covers and upholstery – where the zip should be invisible and not interfere with the backrest.
When a regular zip is better
- For heavy-duty use – jeans, work trousers, backpacks, jackets. Larger teeth are needed – metal or spiral in bigger sizes.
- When the zip is a design feature – contrasting zips, metal teeth, visible decorative pulls.
- When a separable or two-way zip is required – regular zips offer many more options for jackets and bags.
- For bulky and heavy fabrics – thick wool, canvas, leather, where the fine coil of a hidden zip is insufficient.
Sewing differences
A regular zip is sewn into an existing seam – usually centred (with two visible rows of stitching on both sides) or under a flap (stitching visible only on one side). The seam runs a few millimetres from the teeth and remains visible outside.
A hidden zip is sewn before the seam underneath it, using a special hidden zip foot that unfolds the coil. No visible stitching shows outside – the seam lies in the groove next to the coil. This makes hidden zips faster to install in mass production but requires precision: slight misalignment causes the zip to show.
Durability and care
Hidden zips are more delicate. If the garment is too tight, the coil can open under tension, and the smaller, lighter slider may wear out faster with frequent use. For fitted dresses and trousers, the cut should allow easy dressing rather than relying on the zip to “hold” the garment.
Both types require the same care when washing: zip closed, garment turned inside out, moderate temperature. The nylon coil does not rust but should not be ironed directly with a hot iron.
Is a hidden zip the same as a spiral zip?
Technically, a hidden zip is a type of spiral zip – both have a nylon coil. That is why hidden zips are often a subcategory of spiral zips in catalogs. The difference is in the tape and slider construction: a regular spiral zip slider does not work on a hidden zip and vice versa, even if the size is the same.
Examples by product
- Satin cocktail dress – hidden zip at the back, about 50–55 cm, matching fabric colour.
- Straight wool skirt – hidden zip at back or side, about 18–20 cm.
- Men’s suit trousers – regular spiral or metal zip with flap and locking slider.
- Jeans – metal zip No. 4–5 with automatic lock.
- Sports jacket – separable spiral or moulded zip, often under a flap.
- Decorative cushion cover – hidden zip in the bottom seam.
- Backpack – spiral zip with larger size and two sliders.
These examples are guidelines; the final choice depends on design and fabric.
How to choose for a specific model
- Decide if the zip should be visible.
- Assess the load – fitted or loose garment, heavy or light fabric.
- Specify construction – non-separable, separable, two-way.
- Choose size and length according to the opening.
- Select colour matching the fabric swatch.
Hidden and regular zips from Polkom
Polkom manufactures and delivers hidden zips, spiral, metal, and moulded zips, as well as original YKK zips. This lets you source your entire collection from one manufacturer – from dresses to jackets. Send a request with your model descriptions, and we will recommend the right zip for each.
