Deconstructing a zippered pouch
I am doing a building project, and as I was sitting at my kitchen table with the construction manager, he asked me if I could replace the zipper on a tobacco pouch.
Items like this zippered pouch are constructed inside-out. Most or all of the seams are sewn with right sides together, then the whole thing is turned right side out at the end like a collar or pocket flap. As it turns out, the zipper was the very first thing sewn, so we have to take the pouch completely apart to replace the zipper. Not being a smoker, my first surprise was that the pouch is lined in latex rubber. A nasty nicotine color after years of use, this rubber lining keeps the pipe tobacco from drying out, smelling up the place, and staining the leather exterior. The final seam, and the first one we will rip out, binds the two body halves together with a plastic strip. This plastic is not a woven material; it’s embossed with some sort of texture, but it’s a solid material. It is also dried out and cracked, and will have to be replaced. After removing the stitching and old plastic binding, the edges of the body were still stuck together. I was afraid they had been glued with something I would not be able to remove. As it turned out, the leather right sides and latex linings were only sticking to themselves with natural adhesion, and they could be easily pulled apart. Two things became clear at this point. First, the latex lining does an excellent job of keeping the staining and odor from exiting the pouch. The lining side adjacent to the leather is unstained, so nothing is getting through. Second, there was an additional layer of padding between the leather exterior and the lining. It is now totally worn out, but it looks like a thin layer of open cell foam.
Close examination of the remaining seams reveals that the body halves were sewn to the zipper as the second-to-last operation, so those will be the second seams we rip out. They were sewn on a double-needle machine, so there are actually four lines of stitching to remove to separate the body pieces from the zipper. These seams were glued before stitching, but fortunately the glue was something like rubber cement and easily peels away without damaging the leather. We also find that the leather exterior was cut longer than the lining, and the excess has been glued to the top edge of the lining as a clean finish hem. I will leave the leather and the lining attached along this edge. The first seams to be sewn, and the last ones we rip out, attach the zipper tape to leather tabs that make up the rest of the open side of the pouch. The tabs are unlined, but like the body pieces they have been folded over and glued to the zipper tape before stitching. Only a single line of stitching attachs them to the tape. We can now see the distortion of the zipper which caused it to fail. If you are doing seasonally-focused apparel, the long term durability of your garments may not be an issue. But for work clothing, equipment bags, tool cases, and similar items, examining the ways in which they wear out can suggest ways of improving the design for longer lifetimes. In this particular case, I have two observations. First, the edge of the body pieces that attach to the zipper take were almost certainly straight when first cut and sewn. Over the years, this edge has stretched so it is now longer and curved. Second, there was clearly a concentration of stress at the two ends of the zip travel, especially at the closing end where the zipper teeth are almost pulled out of the tape. A redesign that reduces this stress and accommodates the material stretching would be an improvement.
Before closing, I’d like to show some variations on this simple zippered pouch. They won’t win any prizes for style or finish, but these pouches were quickly cut and sewn to store specific contents.
The tobacco pouch was flat, like an envelope; the zipper was one creased edge. These pouches both have some depth, like a bag with four sides and a top and bottom, but they get it in different ways. They also have seams that, like hems, go all the way around. The tobacco pouch has no such seams, the upper microphone pouch has one, and the bottom microphone pouch has two. Both microphone pouches extend the width of the zipper tape to form one side of the pouch, then extend the length of the result. The top pouch wraps the “big zipper tape” around three sides of the pouch, with the remaining sides provided by a single pattern piece. The bottom pouch wraps the “big zipper tape” completely around the middle of the pouch, forming four sides of the pouch, with the remaining two sides provided by separate pattern pieces.
We had a number of microphone cable spools that needed storage. The pattern for the one on the right was sized to hold two of the circular spools, while the pattern for the one on the left was sized to hold three oval spools and some loose adapter cables. Before I forget, these were “interfaced” with cardboard glued to the interior to give their sides some rigidity. Is there such a thing as bas couture?
This is definitely not to scale, but will show you the pattern and sewing differences among these three zippered pouches. Again, they are all sewn inside out, and turned rightside out as the last step.
A future post will cover replacement materials and putting everything back together again.
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