Stitchback Metamorph Pack: Back Panel

I knew this backpack series would take me all summer (and then some) to write! Hopefully, I haven’t put anyone off from making their own bag. It definitely takes a lot of thinking and planning if you want your first pack to be usable, but I hope that by breaking the process down into sections, the project feels much more approachable.

• General fit
• How to prototype (and all the supplies you’ll need)
• Hipbelt
• Shoulder straps
• Frame

Now, we finally get to put it all together! The hipbelt and shoulder straps need to be sewn to the frame, bringing everything together to form the back panel of the bag.

Putting it together

The Stitchback Metamorph pattern explains how to measure your torso length—from the end of your shoulder straps to your hipbelt—to determine their placement on the back panel. Once I had my hipbelt and shoulder straps finished, I didn’t find it too difficult to gauge the placement on my own body and transfer those measurements to the pattern. You will definitely need a friend to help you measure, but after that, the process is fairly straightforward. If you want more detailed instructions, I highly recommend checking out this blog post.

If you are still unsure, take this opportunity to sew a muslin prototype of your back panel to test the overall fit. You can always reuse your actual hipbelt and shoulder straps on the final version later.

To help you visualize, let’s look at a few examples of how the straps and hipbelt should actually fit. When placed correctly, there should be no gaps underneath your straps; the shoulder straps should follow the curve of your shoulder exactly.

Torso LEngth too short

This is less common, but if the distance between your hipbelt and shoulder straps isn’t long enough, you will run into one of two issues. Either the hipbelt will ride up off your hips, or the straps won’t sit tight against your body, causing the weight of the pack to pull away from you.

Torso Length too Long

It is much more common to make the torso length too long, meaning there is too much space between the hipbelt and the shoulder straps. In the blog post I shared above, the Australian Hiker shows an exaggerated version of what this looks like. However, it doesn’t take much effort to find examples all over the internet of bags that just don’t fit right.

If you see a gap underneath the shoulder strap, that strap is doing nothing for you.

Construction

I completely ignored the pattern pieces for constructing the back panel. Instead, I added a zippered section to hold my frame separately from the water bladder pouch, and I stabilized the mesh fabric by sewing it to less stretchy fabic. Here is a breakdown of how I did it:

In the figures below, the colors match my photos. The pink is Challenge Sailcloth EPX 200. The light brown is the accent Challenge Sailcloth 210D. The dark brown is the 1/8 inch spacer mesh.

Outside Back Panel

The original back piece is constructed from four pieces (N, O, P, and Q) plus the shoulder straps. The straps are sewn to piece P and covered by Q to hide the raw edges.

Spacer mesh is quite stretchy compared to Challenge Sailcloth. I added an extra layer of non-stretch 210D behind the spacer mesh to prevent the back panel from distorting. You definitely don’t want to go through all the effort of sewing a bag just to have it stretch out on you!

Inside Back Panel

The original inside back piece uses pieces T and U to hold the plastic frame. I found that this didn’t work well at all.

Instead of using pieces T and U, I added a full-length zippered pocket. I cut my pieces to the full length of the back panel and added a zipper near the top to keep the frame secure.

The water bladder pouch (piece V) remained exactly the same as the original pattern.

Pattern Alterations

The original piece P is a simple rectangle, and the pattern includes a strap placement guide to help you figure out how far from the top of the hipbelt to place your shoulder straps. You simply slide the guide up or down depending on your torso length. However, the pattern doesn’t make any suggestions about widening the shoulder strap placement and that is where our alterations begin.

If you recall from my shoulder strap blog post, we changed the shape of our straps from an S-shape to a more natural J-shape. This meant we also needed to adjust the width and angle where the shoulder straps attach to the pack. I had to move my shoulder straps outward by about 1.1875 inches. Because you need a generous 5/8-inch seam allowance between the shoulder strap and the side to stitch everything together, I widened the top of my pattern by 3/16 of an inch and graded it back to the original width at the bottom. I also adjusted the angle of my straps as needed.

Ryan’s back panel needed a lot more work. I raised the top of his back panel by 5/8 of an inch, but honestly, I probably needed to raise it by 2 or 3 inches. I also widened each side by 1-1/8 inches. His straps had to be placed a full 2-1/4 inches wider than the pattern recommended, which is a significant adjustment! It just goes to show that he is definitely broad-chested and thin-flanked.

Final Fit

Remember, one of the best features of this pattern is that the hipbelt is completely removable and swappable. Although it has taken a lot of work to get to this point, having parts that are replaceable and adjustable makes the effort entirely worth it.

The difference between my old Osprey pack and my new custom pack is just astounding. The straps sit completely flush against my shoulders with absolutely no lifting.

Besides being a much better color, the fit of Ryan’s new pack is infinitely better than his old one.

Personal Aside

I think I have only one more post left in the backpack series, which will cover making the actual bag and sewing it onto the back panel.

As someone who has studied brain function and cognition for 25 years, I sometimes forget that what feels like old news to me isn’t always obvious to most people. With my dad’s dementia, I’ve been able to map where the cell death is happening in his brain based on his behavioral changes and the specific things he is struggling with. It is absolutely perplexing to my family that he is able to retain some functions and abilities while simultaneously losing his mind.

With that cheerful thought, here are some of the most interesting videos I’ve shown during my lectures over the years to demonstrate the fascinating ways our brains can deceive us, while also giving us insight into what role different parts of our brain might play.

If you prefer to dive into a good book, here are a few on the subject that I have enjoyed over the years.

I always get a little wary when neuroscientists write popular science books. It is far too easy for them to project their own pet theories onto the data, slightly warping our understanding of the brain just to fit a narrative, so take these with a grain of salt…