Sewing pre-stretched elastic pocket rims and inserting foam into shoulder straps

[Lester Moore]

Two of the most tedious backpack sewing tasks are making pre-stretched elastic pocket rims and inserting foam into shoulder straps. The videos below show techniques I’ve worked out using simple tools you probably already have at home. There may be better ways or better equipment to do these things, but the techniques below seem to provide consistent results:

Pre-stretched elastic pocket rim:
https://youtu.be/e4qHGPUmKy4

Shoulder strap foam insertion:
https://youtu.be/9j_9Fjoe3gg

For the elastic rims, I use 3/4″ elastic band folded in half and then sew it to the pocket mesh using a zigzag stitch. For the foam insertion guide, I use heavy construction paper with the outside face completely covered in clear packing tape to make it slick.

[Christian K]

Hi Lester! Exactly what I would have said! Thanks for the videos!

Pockets:

I think you commented on a previous post about it, but for my last project I ended up doing something similar using quick clamps to stretch out my elastic to the width I needed.

I got 100 knockoff wonderclips for $8 I think on Amazon? I’m sure you could use pins, but they work GREAT for the stretch pockets. I’ve heard wonderclips are superior than the knockoffs, but I’m not buying them to try it out. They’re $10+ for a 10 or 20 pack. However, for pack builds, you likely wouldn’t need more than 20 on a single seam anyway.

Shoulder Straps:

I just discovered on my last pack that folding the foam in half lengthwise works really well and allows you to get the foam in all the way. Gotta be something with the geometry. SO MUCH LESS tedious and less stressful than spending 20 minutes trying to force it in there. I’ll have to try the paper. Seems worth a go. Sorry for whoever came up with it, but screw using baby powder to “reduce friction”. Tried it… it’s just a mess!

I couldn’t even get the chalk pencil out of black X-PAC without a good rub.

 

Curious what version pack prototype your on now… #17? lol I think I lost track at #6.

[Lester Moore]

The clips seem much easier than pins for most uses – there are extra large ones I sometimes use for some purposes, but the small ones work great most of the time. Instead of using tape to hold multiple layers of fabric together before sewing a seam, I’ve switched to basting stitching – it’s fast, easy and very secure and most of the time, the basting stitch can be left in place.

As for pack version, after # 7 or 8 there have been few changes of relevance – right now # 21 is nearly done and ready to ship. The newest prototype is a set of removable front packs – similar to shoulder strap pouches, but larger and more versatile. I’ve been field testing a 2 L design with an inner zip pocket, outer mesh stretch pocket and new sternum strap design that keeps them from bobbing around.

[Author]

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