G4 Backpack

Posted by: PaHiker

G4 Backpack - 02/12/15 08:25 AM

Hi, new here. I'm sure this pack has been discussed many times, so I hope I am not repeating a prior answered question, at least I could not find is asked before.

I have almost all of the materials needed to make this from old gear I have lying around in my backpacking cabinet. The only exception is the Oxford (Duck?) cloth. Instead of using the oxford I was considering going with the material from the rainfly of my old Eureka tent (fairly heavyweight nylon), or the footprint from my old Sierra Designs Alpha CD, also a fairly heavyweight nylon.

The reasons for this choice include recycling old equipment (I'm a scavenger of sorts), lighter weight than the Oxford, but still pretty durable, and the desire to make the pack for free (okay, so I'm cheep).

Any thoughts on the pros / cons of doing it this way?
Posted by: Pika

Re: G4 Backpack - 02/12/15 10:46 AM

I've made several G-4 packs and variations on that theme. In fact, I just finished one: a variation. In my experience, the Oxford fabric or Cordura fabric is used where it is used because it is abrasion resistant. Tent flies have only minimal need for abrasion resistance and thus the fabric used to make them is not particularly that way.

IMO, using rain fly fabric as a substitute for an abrasion-resistant fabric would be a false economy and a minor weight savings. Quest Outfitters sells Oxford or Cordura by the yard. You will need about $10.00 worth for a pack. I recommend it.
Posted by: PaHiker

Re: G4 Backpack - 02/12/15 11:23 AM

What about using the footprint? It's a much more abrasion resistant material. As I remember, it's not a smooth surface, like the fly, more like a ground tarp.
Posted by: Pika

Re: G4 Backpack - 02/13/15 07:44 AM

The footprint may work, it depends on the material and its coating. My concern is that making a pack properly takes time and effort which may be more-or-less wasted if you use the wrong materials.

With that said, in the past, I basted together a pack from some hideous, bargain shelf, 50 cents per yard, floral print. It took some time and a lot of fussing and the resulting pack looked really weird. But, I wound up with a pattern that has evolved over the years into a pretty good, 12 oz, 42 liter, lightweight pack.

My main issue with the G-4 pack is that it is too big for its suspension system and I don't like the outside pad pocket. YMMV.
Posted by: PaHiker

Re: G4 Backpack - 02/13/15 08:14 AM

I agree with it being too large, my goal is closer to 3500, and I'm not crazy about the mesh pocket in the back. My thinking right now is that this is going to be a first effort, as with the other gear I've built (hammock, stove, etc.). Which is why I want to use on-hand materials. It needs to last one backpack grip in the GC, down to Bright Angel and back, then I can evaluate it and make changes for the next version.

I actually tried my own design for a bagless backpack. It didn't work out well, so I'm moving onto this. I hope to learn enough form it to go back to my design and fix the bugs.
Posted by: Dryer

Re: G4 Backpack - 02/13/15 08:52 PM

I've used a G4 for quite some time and gotta say, it's big but it's light and you don't have to use all that room every time you go out. I've never apologized for too much volume.
That mesh pocket...back and sides, I had reservations too, but, after using the pack, I found more and more things migrating to those pockets so I could have quick access and see what I was grabbing. My pack was made by Glen Van Pesky (contract sewn) before becoming Gossamer Gear and I love the thing. Still looks new. I do use socks in the straps, waist band, no foam padding anywhere. Wonderful pack!
My only mod would be how the top rolls and secures.
Posted by: PaHiker

Re: G4 Backpack - 02/13/15 09:31 PM

I've heard that complaint from a number of people. Most complaints seem to be around the velcro closures. What would you do differently?
Posted by: Dryer

Re: G4 Backpack - 02/14/15 07:37 PM

The closure works and is probably the lightest of options. Modded, I'd sew fastex buckles where the velcro patches are on the pack sides and run a strap across the top. But, again, the current system works and weights nothing. Doubt I'll change mine.
Posted by: carbeque

Re: G4 Backpack - 03/11/15 02:31 PM

I'm intrigued by the idea of building a G4. I just read this review, however:
and I gotta say that most of the feedback I saw from that guy echoes what I'd expect to be the drawbacks of such a pack. Throwing 1 pound at this bad boy sure would go a long way! I'm thinking about building my own, but at this point I'd consider making the following changes:

1) Closed cell foam pads in the belt and shoulder straps. I'd keep them removable, but I doubt I'd ever bother. We're talking a few grams here...

2) Compression straps. It would be great to be able to keep the load contained in a controlled manner. Even if they ran against the main body of the pack, inside of the mesh pockets, it'd be better to have something rather than nothing. Two would be nice.

3) Adjustable straps and latches for the boat bag closure. It could then double as a vertical compression strap.

4) Custom ~.05" thick aluminum sheetmetal insert for Z-rest pad. I have an idea of what this would look like... basically a flat sheet with a slight angle bend somewhere in the middle, and a ~1.5" flange bent over at each end, then bent downward about 0.5". This would insert into the Z-rest and provide a blunt support surface at each end for the pack to bear against in order to provide the needed structure. Without any holes punched in it, it weighs 1.2 pounds, and would be far superior to a plastic frame sheet.

A new diversion for me to ponder... LOL. I do mechanical design for a living, so it's only a matter of time until I try to over-think a piece of backpacking equipment. ;-)

Posted by: PaHiker

Re: G4 Backpack - 03/11/15 03:36 PM

I understand some of the limitations, and the instructions (for a non-sewer) need some work.

I will be using it in 2 weeks when I backpack in AZ, including the GC (S.Kaibab and Bright Angel). I plan on a detailed review when I get back. I can already see some changes I would make, like making the tops of the mesh pockets closable with cords like the top of the bag. The pockets are too large, IMO, to keep things in there securely on mountainous trails.
Posted by: carbeque

Re: G4 Backpack - 03/11/15 11:28 PM

Awesome! Can't wait to hear about it!

I was thinking... my 8-year-old son needs a pack. I wonder if I should build him a G4... it'd be a fun test run, and a really nice pack for my son! I'd just make it out of cordura nylon so he doesn't tear it up. He has a 12" torso right now, so I figure if I shrink the height and width of the pack by about 30%, it should last him a few years.

I'm joining the G4 Yahoo group... thoughts on that?