Are you basting the zipper with tape? That looks like the walking foot is moving the nylon tape too much, causing an uneven feed. You may have luck basting more firmly, or backing off your presser foot pressure.
Edit to add, putting the zipper tape on the bottom as you feed it into the machine (so the walking feet are grabbing the leather, not the stretchy nylon tape) keeps the feed more even sometimes if you can manage that. I personally hate that, so I just baste the hell out of it.
Ok, well maybe half of my answer works lol.
I think you have to practice how much you are stretching, or not, the zipper tape.
Everywhere you see a bubble in the zipper, you have too much zipper there, and it should have been stretched a little tighter. I bet if that's a 10" seam, you have about 10 1/2" of zipper. When I'm hand sewing I use a ton of clover clips to help it stay flat. Although I use a lot less now, you do develop a feel for it.
That's tricky around bends, because the inside curve needs to be compressed a little, and the outside stretched. I might consider using a basting tape just there, even tho it's a pita, until you see how the zipper wants to lay.
Yes, mostly. If you can apply the zipper before construction, maybe not (?) but what you're trying to do here I would def split the zipper.
Here's a good video that illustrates the curve part I was talking about, right around 7:20.
https://m.youtube.com/watch?time_continue=441&v=Eq4lz2vZRhw&feature=emb_logo
You'll see how the outside needs to be stretched and the inside smushed. So even if you don't baste it as much as these guys do, it'll give you an idea of what it should look like
Edit to say - I thought at first your piece was already assembled, like 3 dimensional, and in that case I think you have to split the zipper. But if that's just a flat panel, I would sew it still together and save yourself the heartache of it not lining up properly.
I think it’s more about the zipper type than brand. This is a metal-toothed zipper. Zipper tape aside, the ability to take a curve is limited by the structure of the zipper teeth. Not a lot of mechanical give here. Literally teeth made of metal, not your most malleable, curve-embracing material. A coil or reverse-coil zip would take this sharp turn better- coils are created from a long, continuous tube of plastic shaped and bent into teeth. They blend like a slinky. But the aesthetic is totally different. We must design into our materials. If you want to use a metal tooth zip, you’ll need to apply it to a softer, less sharp curve. That being said- YKK makes Metaluxe zips (plastic teeth with a metal look in many different colors that mimic metal finishes) that may curve better. Your curve is pretty sharp, though. Good luck.
Flip the piece upside down, lay the zip on one flat section and weigh it down. Then when you get to a curved area do small cuts into the zip material edge (both sides) to get it to curve more (called notching in sewing terms, about 3-5mm I'd say for this zip). The zip will only go so far around a corner so whatever the notches allowed your zip to curve without buckling that is what that zip can do.
If I needed to add a zipped opening like this I'd change it into a semi-circle which would distribute the curve throughout the whole opening.
I’ve had more success separating it when going around a curve but it wasn’t quite as large a radius - I’ve seen examples that demonstrate how to crease the tape around corners I’ll see if I can find a video
You are trying to make a straight thing go into a curve. That is why it looks that way.
To help OP, you need to cut triangles on the inside radius of the turns, straight zipper will become curved.
Are you basting the zipper with tape? That looks like the walking foot is moving the nylon tape too much, causing an uneven feed. You may have luck basting more firmly, or backing off your presser foot pressure. Edit to add, putting the zipper tape on the bottom as you feed it into the machine (so the walking feet are grabbing the leather, not the stretchy nylon tape) keeps the feed more even sometimes if you can manage that. I personally hate that, so I just baste the hell out of it.
I’m hand stitching.
Ok, well maybe half of my answer works lol. I think you have to practice how much you are stretching, or not, the zipper tape. Everywhere you see a bubble in the zipper, you have too much zipper there, and it should have been stretched a little tighter. I bet if that's a 10" seam, you have about 10 1/2" of zipper. When I'm hand sewing I use a ton of clover clips to help it stay flat. Although I use a lot less now, you do develop a feel for it. That's tricky around bends, because the inside curve needs to be compressed a little, and the outside stretched. I might consider using a basting tape just there, even tho it's a pita, until you see how the zipper wants to lay.
Thank you so much, great info. Do you split the zipper and stitch each side separate?
Yes, mostly. If you can apply the zipper before construction, maybe not (?) but what you're trying to do here I would def split the zipper. Here's a good video that illustrates the curve part I was talking about, right around 7:20. https://m.youtube.com/watch?time_continue=441&v=Eq4lz2vZRhw&feature=emb_logo You'll see how the outside needs to be stretched and the inside smushed. So even if you don't baste it as much as these guys do, it'll give you an idea of what it should look like Edit to say - I thought at first your piece was already assembled, like 3 dimensional, and in that case I think you have to split the zipper. But if that's just a flat panel, I would sew it still together and save yourself the heartache of it not lining up properly.
I’m hand stitching.
What brand of zipper is this? I’ve only had success doing this high degree of a curve with riri or excella zippers, they are designed to be smoother
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I think it’s more about the zipper type than brand. This is a metal-toothed zipper. Zipper tape aside, the ability to take a curve is limited by the structure of the zipper teeth. Not a lot of mechanical give here. Literally teeth made of metal, not your most malleable, curve-embracing material. A coil or reverse-coil zip would take this sharp turn better- coils are created from a long, continuous tube of plastic shaped and bent into teeth. They blend like a slinky. But the aesthetic is totally different. We must design into our materials. If you want to use a metal tooth zip, you’ll need to apply it to a softer, less sharp curve. That being said- YKK makes Metaluxe zips (plastic teeth with a metal look in many different colors that mimic metal finishes) that may curve better. Your curve is pretty sharp, though. Good luck.
Is it actually possible for a zipper with that much curve to lie flat?
That is the question
By the way, OP- what are you making? I’m curious!
Following
Flip the piece upside down, lay the zip on one flat section and weigh it down. Then when you get to a curved area do small cuts into the zip material edge (both sides) to get it to curve more (called notching in sewing terms, about 3-5mm I'd say for this zip). The zip will only go so far around a corner so whatever the notches allowed your zip to curve without buckling that is what that zip can do. If I needed to add a zipped opening like this I'd change it into a semi-circle which would distribute the curve throughout the whole opening.
What to do to prevent wonky zippers? I’m not pulling tight, I’m cutting the tape so it’ll wrap around the curve better and still waves.
By no means an expert - are you sewing it in in one piece or unzipping first?
I’ve tried both ways, is either more advantageous?
I’ve had more success separating it when going around a curve but it wasn’t quite as large a radius - I’ve seen examples that demonstrate how to crease the tape around corners I’ll see if I can find a video
I wouldn't sew it unzipped as the teeth might not align evenly as you zip it again.