Shorten a separating zipper

From another forum (reprinted with permission):

I am making a fleece jacket that uses a separating zipper. Unfortunately, the zipper size recommended is too short, probably because I was using thick fleece and it enlarged when I was cutting the pattern out. So I had to buy a larger size that is too large. The zipper has nylon teeth. I know how to shorten a regular zipper, but I need to shorten this from the top because it is separating. Any ideas would be really appreciated. Thanks.

My first piece of advice is to recut the jacket front to eliminate the growth, and correct the back accordingly too. If the piece has grown like that, you may find other surprises mid process when you’re least capable of dealing with it.

Secondly, be sure to fuse that zipper inset area, keeping the length stable. There are two reasons for this but the first is that people will mistakenly fail to fuse zipper inset areas (or anything) on heavier weight goods reasoning the goods are already heavy enough but you have to look at this comparatively. The goods are heavier than what you may be used to working with but look at that area in relation to the rest of the goods; those areas haven’t been sliced down the middle and forced to perform the work of entry and exiting from the garment. The closure must withstand performance commensurate with the weight of the rest of the garment. As a rule of thumb, fuse all outside edges as these get the most wear and tear.

The second reason to fuse that area on this particular fabric -fleece- is that when you’re sewing in that zipper, it is common for the fleece to grow lengthwise in process. Fusible will keep the area length stable. I like to use that nylon tricot fusible for this job. If you’re concerned the knit fusible will also grow, cut it crossgrain. Experiment with a strip of fused fleece, machine baste in the zipper tape to test it. I’ve done it and have had excellent results.

With regard to sewing in the zipper itself, I just noticed I don’t have a separating zipper tutorial on site. Hmmm. [Note to self: use photos from the vintage blouse step by step tutorial (2005) for this. Someone could also email me to remind me if I haven’t done this within the next week or so.

Back to shortening the zipper -nylon, metal or otherwise, this is really easy! I will show you using a separating zipper with metal teeth. First mark off the proper length (below).

Using a pair of pliers, pull the teeth off of the tape. Just grip one individual tooth at a time and give it a good tug. While my zipper has metal teeth, if anything, this is easier to do on plastic zippers. Sometimes the plastic teeth break but this just means you haven’t grabbed the base of the tooth, reposition your pliers and tug.

Below you can see I’ve cleared away all of the excess teeth on both sides leaving about 3/4″ clearance. I’d recommend at least 5/8″ of clearance for heavier goods. This gives an allowance of 1/4″ for outside edge seam allowance, 1/4″ for top stitching and a remaining 1/8″ for turn of cloth (essential on heavy goods).

Once you’ve cleaned the edges of excess teeth, then you can cut the zipper tape (below).

And that’s all there is to it.
Process review: lapped zipper
Lapped zipper template
Lapped zipper construction
Lapped zipper specs
Centered zipper template
Centered zipper construction
Invisible zipper tutorial pt.1
Invisible zipper tutorial pt.2
Shorten a separating zipper
Zippered welt pocket tutorial
Deconstructing a zippered pouch
Zippered welt pockets

Get New Posts by Email


  1. Kathleen says:

    The puller doesn’t just zip right off the top when you do this? Does the folded tape edge keep it from coming off?

    Good point! Thanks for bringing that up.
    One, before it’s sewn in, you can put in top stops, little metal bendy things that wrap around the tape at the top. Me, I’ve never used those. The reason is, once the thing is sewn and finished in the garment, the slide won’t come off; the top of the garment edge secures it. Second, if during the process of sewing it the slide does come off, it’s a separating zipper; you can feed the slider right back on, no problem.

  2. Roseana Auten says:

    Fusing interfacing to fleece? I’ve been told, No can do because the fleece can’t take the sustained heat required to get Fusi-Knit to bond. Enlighten me!

  3. J C Sprowls says:

    Then, try cool fuse interfacing. I don’t recall any specific product names at the moment. But, I do recall that the adhesive bonds at (or below) 280F; and, was specifically designed as a result of microfibres coming onto the market.

  4. Carol Kimball says:

    Cool fuse tape is (now) used extensively by the leather industry. I got some at a Kathryn Brenne workshop. Search “Meet Henry Hibbard” for a possible link to source(s)?

    Google “cool fuse interfacing” for other sources.

  5. Kathleen says:

    Ack! I just found some of this here and my, it is expensive. $4.70 for goods 20″ wide. And, they’re out of stock so I guess it sells well. The stuff I have is three times as wide, maybe I should sell it for $14 a yard? How about $7 a yard?

    If anybody is interested, you can have it for the price of a (4 yd minimum) $30 donation to the marathon I’m raising money for which will include shipping. What a deal, interfacing AND it’s a tax deductible charitable expense.

  6. Sabine says:

    Is there a specific reason why you cut the teeth off first and then cut the zipper tape?
    I always do it the other way around, cutting the tape first, 6 teeth above finished length for nylon and 8 teeth above finished length for metal teeth zippers and generally just use sidecutters to cut off the teeth . I am also in the process of writing a tutorial for basic alterations, which includes sewing in separable zippers. Would you like me to share? There will be pictures too.

  7. Kathleen says:

    This is a woven tape that will fray. Cutting off the tape last minimizes the stressors on the weave. I also trim *plastic* teeth with side cutters and then pull off the remnants but these teeth are metal and yeah, the side cutters would probably cut those too but why mar the edge of the cutting surface if pulling is neater and cleaner? Feel free to link to the entry.

  8. Sam says:

    Hi have to disagree with the slide not coming off once the garment is finished. I have tried this method a couple of different time and both times have had to alter the zipper so it wouldn’t slide off at the top. I’m checking into buying the metal stops. Sounds like those will save ALOT of headache.

  9. Kris says:

    What kind of zippers are you using that the teeth come off easily? I’ve tried modifying both plastic and metal teeth zippers, and it is VERY difficult! The teeth do not come off easily with just a “tug” with pliers, and the plastic ones don’t break easily either. I might think it was just that I don’t have enough strength, but in both cases I asked my Dad to help and HE was straining. I was lucky that both times I only needed to remove 4 teeth, because it took him as much effort as moving a queen bed, desk, and dresser had two weeks before.

  10. Sabine says:

    Kris….you have to pull the tooth along the zipper tape, not simply yank away, then it’s a lot easier. I got trained to just cut them off with side-cutters however and always do it that way. It is not recommended, as you can damage the zipper tape with the cutters, but practice makes perfect….

  11. kelli says:

    I also have the problem of the zipper slide coming off. I haven’t found stoppers yet, but I will have to get some! I found the teeth very hard to remove so I ended up just clipping them off right along the edge and then using a lighter to melt the edge of the poly/nylon tape so it doesn’t fray. Works quite well.

  12. Melody K. Gardner says:

    Kathleen, this is Ody from PR. Thanks for the great tute!!! I am making a vest with a visible zipper and had to shorten it. You just saved my life. How are your cats!!! Melody Kerr Gardner

  13. Rhonda says:

    What are the best plyers to pull off zipper teeth. I’m desperate to know. Please don’t tell me that any kind will work….many are too hard thick to just grab a tooth.

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.