Pattern no. 003
Broken zipper: repair or replace?
NaynaCrafty Nayna, Denison TX
5 min read
The three things that actually break
Almost every zipper that comes through the sewing room has failed in one of three ways, and they are not equally serious. Knowing which one you have tells you roughly what the job is before you ever hand it over.
The slider wears out. The slider is the small metal or plastic piece you pull. Inside it there is a narrow channel that squeezes the two rows of teeth together as it passes. Over years of use that channel spreads slightly, and once it is too wide the teeth go in but do not lock. The symptom is unmistakable: you zip it all the way up, and it splits open behind the slider. The teeth are fine. The part that joins them is not.
Teeth break or go missing. A tooth snaps off, a few get bent after being forced over a jammed thread, or a section tears away from the fabric tape. Now there is a gap the slider cannot bridge, and no slider will fix it. This zipper is replaced.
The pull tab comes off. The little tab that hangs from the slider breaks away, leaving a slider body you cannot grip. This is the smallest of the three and often the quickest thing anyone fixes all week.
Zippers are tested as mechanical components, not just sewn trim. The ASTM standard for zippers covers strength tests for exactly these parts, including how much force it takes to pull a slider off and to separate the teeth, which is a useful reminder that a zipper is a machine with wearing parts.
Work out which one yours is
Answer these three questions and the tool will tell you which job you are probably looking at.
Repair or replace?
A guide, not a diagnosis. The real answer comes from looking at the garment, and a photo with your ticket usually settles it.
Do not worry about getting it exactly right. It is a guide, not a diagnosis, and the real answer comes from looking at the garment. What it does do is tell you whether you are likely facing the small job or the bigger one before you plan around it.
If the teeth are all there and it still splits open, the zipper is usually fine. The slider is not.
What replacing a zipper involves
Replacing a zipper is more work than it looks, and it is worth understanding why, because it explains the difference in price and time between a dress and a lined coat.
The old zipper has to come out without damaging the fabric around it, which means unpicking the seam stitch by stitch rather than cutting. The new zipper has to match the old one in length, weight and type, and it has to be the right kind: a dress usually takes an invisible zipper, jeans take a short metal one, a jacket takes a separating zipper that comes apart at the bottom. Then it is sewn in so the seam lies flat and the fabric on each side meets evenly, which is the part that separates a good job from an obvious one.
On a lined garment there is a second round of all of that, because the lining has to be opened to reach the seam and closed again afterward, often by hand.
Coats, boots and heavy duty zippers
Heavier zippers fail differently. A separating zipper on a winter coat has to line up perfectly at the bottom before it will start, and when the little box at the base bends, the coat will not zip at all even though nothing is broken further up. That bottom hardware is part of the zipper, so a bent one means a new zipper rather than a new slider.
The other common heavy duty case around here is boots and bags. The zipper tapes on those are thicker and the teeth are larger, so they need a matching replacement rather than a dress weight zipper, and they take a stronger needle to sew. Bring the item in and Nayna will tell you whether it is something she can take on.
Invisible zippers and dresses
Dresses usually use an invisible zipper, which is a different animal from the one in a pair of jeans. The teeth are rolled to the back so that when it is closed, all you see is a seam. That is what makes it look good, and it is also what makes it less forgiving.
An invisible zipper has to be sewn with the seam pressed open and the stitching running right alongside the coil, and it has to be the right length for the opening, because there is no spare to cut off at the top on most dresses. Put one in slightly crooked and the seam waves, which shows across a room on a fitted dress.
This is also why a dress zipper that is failing is worth dealing with before an event rather than after. If it splits on a fitted bodice, there is nothing holding the dress closed.
When the fabric is the real problem
Here is the case people do not expect. Sometimes the zipper is fine and the fabric beside it has given up.
On an old jacket or a well worn pair of jeans, the cloth the zipper is sewn into wears thin along the stitching line, or tears away at the top where the waistband takes the strain. Put a brand new zipper into weak fabric and it pulls out again, because the zipper was never the weak point.
The fix is to reinforce the fabric first, usually with an interfacing or a patch behind the seam, and then set the new zipper into something strong enough to hold it. That is worth knowing because it explains why two jobs that sound identical on the phone can be quite different once the garment is on the table.
It is also why a photograph helps. A close up of the top of the zipper, where it meets the waistband or the collar, usually shows whether the cloth is sound.
What a good job looks like
When a replacement is done well, there is very little to see, and that is the point. The seam lies flat with no ripple along its length. The two sides meet evenly, so a pattern, a stripe or a waistband lines up across the closed zipper. The stitching runs at a constant distance from the teeth. The slider runs the whole way without catching at the top or the bottom. On a lined garment the lining is closed neatly and sits free of the zipper rather than catching in it.
Those are reasonable things to check when you pick a garment up, and they are the same things Nayna checks before she calls it finished.
Making a zipper last
- Do not force a stuck zipper. Most jams are a thread or a bit of lining caught in the teeth. Ease it back, free the fabric, then zip.
- Close zippers before washing. An open zipper flails around the drum and bends teeth, and it catches on everything else in the load.
- Rub a graphite pencil along a stiff zipper. The graphite acts as a dry lubricant and does not stain the way oil does.
- If it starts splitting now and then, bring it in before it splits for good. A worn slider is a small job. A torn tape is not.
And if you are not sure which of the three you are looking at, send a photo with your ticket. A close up of the closed zipper usually answers it.
Questions people ask
Can a zipper be fixed without replacing it?
Often yes. If every tooth is still there and the zipper splits open after you close it, the slider has worn and a new slider usually solves it without touching the rest of the zipper.
How do I know if the zipper needs replacing?
Look along the closed zipper for a gap where teeth are missing, bent or pulled off the tape. Damage to the teeth themselves means the zipper is replaced rather than repaired.
Can you replace the zipper in a jacket or a coat?
Yes. Jackets, coats, pants and dresses are all common. A lined coat takes longer because the lining has to be opened and closed again by hand.
Do you replace zippers for Sherman customers?
Yes. Nayna works from her home sewing room in Denison and takes zipper work from Sherman, Pottsboro and across Grayson County.
Is it worth repairing a zipper on an old jacket?
Usually. A new zipper costs a fraction of a new coat, and on a jacket that fits well it is almost always the better call. Send a photo with your ticket and Nayna will give you a plain answer.
