Shoulder bag

a handsome cover over the bag’s zipper

A friend of mine asked me to make a sort-of complicated shoulder bag for a friend of hers for Christmas. I winced and said yes — but I admitted that it wouldn’t be before Christmas, and that it might take a while. Complicated shoulder bags are hard, my friends… and the more elements that are in them, the harder it becomes. That’s especially true when we’re talking about bags like this one.

The core of the problem is this: A bag like this is expected to be waterproof or at least water resistant. That means lining it with a fabric like this gray ripstop nylon — which is fussy, difficult-to-impossible to iron, and rarely behaves as expected. You’ve also got durability problems, which means that you need to use a sturdy, heavy canvas like this one, left over from making a pirate coat many moons ago for another friend. The combination of a fussy and un-ironable fabric with a heavy textile that needs lots of ironing… plus two different kinds of three lengths of zipper… is a little bit of a technical mess.

unzip the main compartment for three divided mini-pockets!

The results… are not pretty. They’re not bad. But there’s a reason I don’t build welt pockets all that often, friends (welt pockets are the ones with the inset zipper, like the one in the third/bottom picture. And the creation of three pockets with zippers was a technical challenge that I wasn’t expecting was going to be anywhere near so hard.

There’s also the question of how you build such a bag. Because let me tell you… the biggest challenge in building a bag like this is not sizing the pieces. I spent a lot of time with pieces of big graph paper for making patterns — think 1″ squares = 1 inch. The stuff is marvelous, and I’d suggest it for those of you who need gaming mats, if pattern-making graph paper wasn’t as expensive and non-reusable as one of those dry-erase roll-up grid mats that D&D gamers use. I made a half-dozen templates for pieces, and used those to dry-fit the pieces, and then sewed them.

exterior ‘pockets’ for pens, protected by the cover, and a coin purse for feeding the meter

The pieces turned out not to be the problem. Your eighth grade math turned out to be the problem.

Remember PEMDAS? It was the reminder of order of operations in your algebra homework:

  • Parentheses
  • Exponents
  • Multiplication
  • Division
  • Addition
  • Subtraction

The problem in designing this bag was not the sizes of pieces. It was the order of operations. In what order should the pieces of this bag be assembled?

I’ve now made two prototypes of this bag, and all the photographs are of the second bag. We have the following features:

  • A foldover flap, to protect the bag’s exterior pockets
  • a trio of compartments outside for pens, a small “to do” notebook (photo 3)
  • A coin purse on the front for parking meters
  • A zippered main compartment with a zipper that’s high on one side and low on the other (photo 2)
  • An interior compartment with three divided sections.
  • A back zippered pocket so that important documents can be hid on the side facing the wearer’s body.
  • Seams reinforced with twill tape

Let me come back to the Order of Operations problem. Here’s what I’ve learned:

  1. Assemble the panel that will be the outside compartments
  2. Cut the slot for the zipper on the front, and install coin purse pocket
  3. Cut the back panel’s zipper, install zipper and documents pouch.
  4. Attach front edge of main compartment zipper to front panel.

There then comes a step 5 followed by additional steps up to 12-ish… and then

  • Ta-daa! Finished bag!

I built the bag, but I know where the problem in the design is:

  • A. The lining of the zipper panel has to be attached to the zipper panel shell before it can be sewn to the front or back panel.
  • B. Once the zipper panel lining is attached to the zipper panel, it will be in the way while attaching the front of the bag to the front of the zipper panel;
  • C. Once the bag’s front is attached to the zipper panel, it may be impossible to attach the back of the bag to the zipper panel.

Currently I don’t know how to solve this problem. However, I’m hoping that if I sleep on it overnight, a solution will occur to me.

Would you be interested in buying this pattern as a PDF when I open my Etsy store again?

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