October 24, 2013
Before we started Andrew told me that designing a bag is similar to building a house: the frame goes up fast but everything else takes a long time. That has certainly been our experience. Getting to the first round prototype was relatively easy but now there are so many additional details to figure out. This week we spent a lot of time on seam lines, features, fabrics, and the mounting system. I wouldn’t be surprised if we go through at least 4-5 prototype rounds before we even approach a factory.
On the one hand I’m really excited to get to a finished product; but on the other hand there is a lot to be said for progressing slowly and taking time to reflect between rounds. I’m very glad we decided to design around physical prototypes instead of computer illustrations. I see now that a lot would be lost on a computer. Nothing beats having a prototype that we can touch and feel, even if it’s just a rough approximation of our final idea. Here’s the current prototype mounted on Andrew’s KLR for a test ride.
Some things we’re discussing now:
Fabric: in the latest proto we used a 34 oz PVC for the outer facing panel. It is extremely thick and abrasion resistant and we like it so far. On the side panels we used a 1000d nylon (similar to cordura), but we’re not too crazy about it. Instead we’re going to experiment with “Ballistic” nylon/cordura, a fabric that was originally designed for military flak jackets and which is now used on a lot of outdoor and tactical equipment as well.
Compression: We want the pannier to have a lot of expansion/compression capabilities. Top down compression is supplied by the roll top, but for side compression we need compression straps. Our current prototype has 4 straps, two on each side, and they pull against the front stiffener, effectively sandwiching the contents of the bag between the stiffener and the rear attachment plate. This makes for a very secure load and clean look, and seems to work quite well. We are also planning to add a removable compression strap on the top, which would go over the roll top.
Keepers: One issue with compression straps is that when the bag is fully compressed there are a lot of loose straps that flap around in the wind. This looks crappy, plus it creates a risk that the straps catch on a moving part or rest on the tail pipe and melt. We need to find a way to control the excess strap material. Some options we’re considering:
Each of these has it’s own pluses/minuses. More testing required.
Pocket Closure: Our original external pocket had a zipper closure but we’re concerned about zipper failure, so we want to experiment with a roll top closure on the pocket. We’d like to avoid zippers if possible, because those are often the first things to fail over time.
Clips, Buckles, & Handles: we’re planning to use aluminum in all the high impact/abrasion areas. This will cost a lot more than plastic but it will also be a lot more durable. We have a parts book from the buckle factory and are sorting through it to find ones we like.
This week we also made more progress on the mounting system doing our home-made prototypes in MDF wood. We’re meeting with Hein next week and would like to get him started on the CAD drawings so we can machine our next round of prototypes in HDPE.
Also this week we started brainstorming our duffle design, lots more to follow on that.
Oh yeah… and there was more of this: