We love them. We (sometimes) fear sewing with them. In some cases, practice is the best instructor. That helps, of course, but a few well-applied tools can make inserting zippers into a knit garment much easier.
This is what might happen if you just grab a zipper and sew a knit fabric to it:
The clip is holding the fabric to the zipper halfway down the test seam. What you can see just in front of the clip is what I call “the bubble of doom.” Here, it’s showing me that the fabric is stretching as I sew. The zipper tape isn’t stretchy, so, as I sew (and stretch) along, the fabric is growing longer than the non-stretchy zipper tape.
There are a few things I could do to reduce the fabric’s stretching. I could lower the presser foot pressure. I could pin the edge with a pin every inch.
I could also call in reinforcements. In this case, I like to add two helpers to my team, so to speak.
Enter one of my favorite sewing tools: wash away wonder tape.
In my opinion, using wash away wonder tape is like having access to the perfect type of pin or instant basting. It’s perfect because it serves as pins and basting you never have to take out, because it just goes away in the first wash!
Simply stick the tape along the edge of your zipper tape, remove the paper backing, and stick your fabric to your zipper edge. Adjust and readjust until you’re happy with it. Then, sew!
Side note: mark the line where two seams should match up with chalk. It will save you lots of guesswork!
This looks pretty good. The tape helped a lot! To be honest, though, the topstitching was kind of hard to manage and it’s also not laying as flat as I would like.
Enter my second helpful tool. In this test, I’m trying 1-inch-wide fusible tricot strips. I’m fusing with an iron set to “wool” and using a tissue press cloth.
I also switched back to my walking foot for topstitching. I think it made it easier to control. This machine can be set with the needle in the left position, so it makes topstitching with a walking foot easier.
Final results. Wonder tape used on the left. On the right, fusible tricot strips and wonder tape were used together.
I think the one one the left is fine, but the one on the right does look a little neater. Also, the fused edge held the seam allowances more flat as I sewed, which does make that bump easier to stitch over.
One final note: the fused edge did “draw up” a little. It’s still a little stretchy, so just make sure your fused edge isn’t shorter than it should be by comparing it to your zipper tape before you sew. If it has drawn up, you can gently stretch it to the correct length when you baste to the zipper tape using wash away wonder tape.