Musing in the Desert: Custom SAR pack project: packbag

I know I said the next step in the project was the lower portion of the suspension. However, on due reflection, I realized that it would be easier to make the pack bag and then build the suspension into it rather than doing something cute involving building the two parts separately and joining them after the fact. Hence, the next step in actuality was to create the packbag.

Pretty sweet little duffel at this point, with no straps or frame

This post is going to be comparatively light on images. For one, it's not complicated. It's basically like building a cardboard box, but with fabric. Ya stick the edges together. Also, I kind of got sucked into the project and discovered myself with a completed bag and very few pictures. However, for what it's worth, let's talk about building a bag.

Bananas for scale.

First off, this is the longest zipper I've ever worked with. It's nearly as tall as me, and I put 4 zipper heads on it. The reasons will become apparent later.

Finishing zipper ends

One thing to remember with unfinished zippers, if you just buy the tape and put on your own heads: there's nothing holding the end together. Without something to do so, it'll come apart, which makes for sad days. You can get little metal clips that are specifically designed for the purpose, but I just put a couple stitches around it, as seen above.

A note about making bags and pouches: build them inside out. What I mean by this is that if you form all your seams by pinching the two pieces of fabric along an edge and stitching the edges flush together, then turn the pocket or bag right-side-out after you finish, it ends up looking much more professional. See below; unfortunately the thread and the fabric are all orange, so you may not see what I'm talking about.

Ugly inside of seam

Outside of the same seam

Zipper sewing

On sewing zippers: first, I have no idea what a zipper foot is. I've never used one. I probably should, but I don't.

I use three seams on each zipper. The first is to hold the zipper to the fabric, and is sewn inside out, as seen above. Next I do a zigzag stitch to keep the edge of the fabric from fraying. Finally, I flip it right side out and run another seam along the very edge of the fabric to keep it from folding into the zipper track and making a mess when I'm trying to unzip the bag.

An additonal word on zippers: if the zipper is not straight, cut the fabric so that the zipper follows a curve, rather than turning a right angle. This makes it much easier to sew, since zippers generally aren't that flexible, and also eases zipping and unzipping. I find that a 4-5" radius curve, drawn with a drafting compass, works well.

Inside of zipper showing three seams

Final seam, which is the only one visible from outside the bag.

So, on to my ridiculous zipper design for this bag. The zipper wraps around the top of the bag, runs down the side, and then wraps around the bottom. It's as if I took the typical top opening, sleeping bag compartment, and side zipper seen on a commercial hiking pack and made them all one zipper. Why? Because then I can do this:

Fully unzipped, with hydration system in place

If I unzip the thing all the way, the bag lays virtually flat. While I may very, very rarely do that in the field, since all my stuff would go everywhere, it could be useful for inventorying, packing and unpacking gear.

The real utility, however, is in flexibility. With this system, I don't have to play guessing games about which zipper is closest to the stuff sack that I need; if I happen to start opening at the wrong end, I can just continue to unzip it until I find what I'm after.

That's the reason I installed 4 zipper pulls. There's one at either end of the zipper so I can open the top or bottom like an industry-standard sleeping bag compartment, and then there's a pair in the middle.

Opening from the top

Opening from the bottom

Opening from side, like a duffel

I have to admit that I didn't come up with this idea on my lonesome. I saw it at REI in a climbing pack when I was 17, went 'that's neat,' and promptly forgot all about it. However, it popped back into my head when I was designing this pack, and I figured I'd give it a go.

One caution about zippers: you don't want a zipper to be supporting a load. The way to fix that in a pack like this with huge zips is to make sure to have compression straps crossing the zipper, taking the weight off the zip itself. You'll be able to see more clearly once I actually get to installing the compression straps.

Speaking of compression straps, I stitched the top pocket onto this bag with channels for the vertical compression straps. Hopefully this works as well in real life as it does in my head.

Compression strap channel, modeled with yardstick

I decided that the pack needed a small top compartment for little stuff like maps, snacks, my headlamp, and that sort of thing. I stuck with a short zipper, because the pouch is small enough not to demand a bigger one. As you can see below, it's just about filled with a can of CLP, a stethoscope, and my headlamp (no rhyme or reason to why I grabbed that particular stuff, it was just the first stuff to come to hand).

Top pocket laid out flat

Top pocket finished

Top pocket open.

For finishing touches on this stage, I added guides for the compression straps to keep them from sliding off the bag when loose, and attachment buckles for my hydration system.

hydration attachment

Close up of hydration attachment

I stitched a piece of 1" webbing to the fabric opposite the hydration clips, so that the entire weight of my 3L reservoir wasn't pulling on such a tiny patch of thin fabric.