r/myog • u/QuietTurtleSprinting • 1d ago
Question Best seam for bear bag
I am planning on making my own bear bag using something like Ultra 400 or 800. The bag would be a draw string (UHMWPE rope) closure similar to Ursak. There would be one seam down the length of the bag and one closing the bottom.
My question is, what would the strongest seam be? My first thought is a flat felled seam but I don't think it's possible to sew a flat felled seam on a cylinder without specialized equipment. I have a simple domestic machine. Are there any other strong seams that would be suitable? French seam maybe? Or maybe someone knows a secret method of sewing a flat felled seam on a cylinder?
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u/Napkin_Manifesto 1d ago
Couldn’t find a name for it, but it’s a felled seam that’s closely topstitched.
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u/broom_rocket 1d ago
Flat felled seams on the main body leave the stitching vulnerable on the outside. IMO a French seam with several finishing stitches would be strongest, but that may leave the ultra fabrics vulnerable to delam at the seam?
I'm not sure using the thinner threads a domestic machine can handle would be adequate. The drawstring channel need to resist however hard a bear will yank on the bag. Ursack uses 4 rows of heavy duty thread there. You may want twice that with thinner thread.
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u/peopleclapping 1d ago edited 1d ago
Flat felling a cylinder is exactly what people are doing when they flat fell pant legs. Look up videos of flat felling pants; you end up scrunching it up like a donut.
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u/QuietTurtleSprinting 1d ago
This is exactly what I was looking for. I tried in vain to find a video like this, there are so many tutorials showing how to do a flat felled seam using two small pieces of fabric. It's the scrunching the fabric up like a donut that made it click and seeing her do that really helped understand how to do it. Thanks for sharing that video.
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u/ottermupps 1d ago
A french seam is not inherently stronger than just two passes of stitching on a normal seam, the benefit of a french seam is that the raw edges are hidden on both sides and it's very easy to sew. I would flat fell this seam, you can acheive that with some careful fabric fiddling. As long as the tube is at least as wide as it is tall (or no more than twice the width in height, if you want to sew it from both ends), then you should be able to carefully sew a flat felled seam. Just try it with some cotton, make an 8" tall and wide cylinder and see what I mean.