I’ve been meaning to write about this for a while and a recent thread in the Gear forum sparked me to finally do it. These are two attempts at making alternate back pads for my MYOG packs using the arc blast frame.
The first option is very well tested with quite a few trips on it:
The pad is made with 3d mesh, 1/4″ foam and Xpac. The webbing that the cord ties into (actually folded over hypalon rather than webbing) is sewn ONLY to the xpac – not through the foam. The foam sticks out a bit on each side so that it’s wider than my shoulder blades.
The effect is a nice, comfy foam pad that doesn’t irritate my shoulder blades at all. It sits pretty much centered on the blades and the rest of the pack does not touch my back.
The second back pad I’ve made is for a prototype lightweight canyoneering pack, and it’s a very different style – back to mesh, but where the webbing is not continuous through the pad, but rather sewn onto each end. There are reinforcement patches to spread the load.
Then the edges of the pad taper down to another piece of webbing that goes behind the stays and gives the pad a curved edge. I tried to make it adjustable but that didn’t work well so I just found the right length through trial and error. Here’s a photo:
So far the pad is pretty comfy (one 4-day trip on it) but it remains to be seen how well it works in the long term. There are some potential failures, namely the mesh ripping or stretching along the lines of tension. But so far the reinforcement patches seem to be doing a good job of spreading the load. I used heavy duty polyester mesh so that should help with the stretching (and hopefully be durable enough for canyoneering).
That said, I’m going to hit that pack with the seam ripper, because I don’t like how I did the frame on it. It’s a rectangle made from Quest tent poles and 90 degree connectors. JB weld holds the connectors and the horizontal bars together to prevent frame twist. The vertical poles are cold set with about a 1.5″ deflection (tensioned to 2″ deflection with the back pad).
It’s my first time trying to put a piece of the frame across the back of the hip belt and I am not a fan of it, at least the design I came up with. My previous packs have had the bottom of the two stays not connected and that is much more comfortable. With the connected one I can feel the hipbelt changing the natural motion of my pelvis when it’s cinched tight. That is very disconcerting and possibly a recipe for an injury if I were to use it long term. So back to the drawing board on that design.
