Need Suggestions for Pack

I'm attaching a couple of pictures (links, I mean...problem with Photobucket) of one of my homemade packs, of course hoping you'll "ooh!" and "ahh!" appreciatively, but mainly in the hope that you'll have some suggestions. I'm thinking of making another one, maybe similar, but a bit lighter. The one in the picture weighs 41.7oz. and I've made another using lighter materials that weighs 36.4oz. I haven't used the lighter one much, due to an ill-advised shoulder strap experimentthat worked, but I didn't care for much, and it would be complicated to change it.

The pack pictured uses 330d Cordura for the back and bottom, 400d pack cloth for the rest. There's an extension collar made of 1.9oz. coated ripstop. The inside surface of the hipbelt and shoulder straps are a soft-shell fabric laminated to 1/2" closed cell foam. The back pad is the same fabric laminated to 1/8" closed cell foam. The lumbar pad is 330d Cordura, and the padding is 1/2" firm open cell foam laminated to 1/2" closed
cell foam, with a thin (about .032") piece of fiberglass PC board material behind it, to spread out the pressure of the aluminum stays. The stays are 1/2"x1/8" 7075-T6 aluminum, which is springy and takes a set less easily than the common 6061 alloy.

The lighter pack mentioned above is much the same, except 1.9oz ripstop instead of the 400d pack cloth, and the stays are 3/4" wide (this was before I discovered the 7075 aluminum), and 3/8" closed cell foam instead of 1/2".

So, I'm thinking of 1.9oz. silnylon for the main pack. Seattle Fabrics carries this - it's heavier than the silnylon used for tarps. It's actual weight is 2.3oz/sq. yd., slightly lighter than PU coated ripstop, a bit tougher, and not slippery. I have a piece of it, but it's bright yellow, and I'm not sure
I want a bright yellow pack. Leaning toward the light green.

Probably still going to use 330d Cordura for the back and bottom, but I'm open to suggestions here. Needs to be fairly sturdy, as the hipbelt and shoulder straps are sewn to it, and the bottom needs to be fairly abrasion resistant.

The V-stays work well, but I'm open to other ideas. My one experience with a frameless pack (Ray-Way style) leads me to believe that I probably won't be happy without something more than a rolled-up sleeping pad for a frame. One idea I've considered is a single vertical stay, with the shoulder straps attached higher and farther apart, like the Ray-Way pack, and no load lifters, since there'd be nothing to attach them to. My frameless pack experience wasn't all bad, though, so I haven't completely dismissed it.

Thinking of eliminating the top and side pockets, but with light material they don't add much more weight than the stow bags I'd have to use to store the little stuff. And they're much more convenient for things I want easy access to (raingear, TP, sunblock, etc.). I realize they're not stylish or hip

Also considering a roll-top closure if I eliminate the top pocket. Any thoughts on drawstring vs. drybag style closures?

The mesh used in the side and back pockets is fairly heavy at about 5oz./sq.yd. Lighter mesh might not be durable enough for water bottle pockets, so thinking of silnylon here, too. I have some powermesh (stretchy stuff) that I could use for the back mesh pocket and maybe eliminate the compression straps, replacing it with light bungee cord. I've seen it on commercial packs, but not sure of durability, and would be interested in your experiences with it.

I've noticed that both these packs tend to sag a bit, that is, the bottom sags below the lower edge of the hipbelt. Not a problem, really, it just bugs me a little. If the upper side pockets were eliminated, I could put a couple of angled compression straps there to maybe correct it. Somewhere I
saw side compression "straps" made from 1/8" nylon cord. Anybody done that?

The main compartment is 24"x12"x8". Thinking of making it smaller.

These packs have worked well, and are more comfortable than any commercial pack I've tried, although I've only tried the more modern ones in the store. The goal is to keep the comfort and ability to carry a heavier load if I ever feel the need, but reduce the weight as much as possible.

Long, windy post, I know...sorry.

http://i350.photobucket.com/albums/q438/WilliiamGK/Tan%20pack-front_zpswmwgrqlp.jpg

http://i350.photobucket.com/albums/q438/WilliiamGK/Tan%20pack-back_zpsubkyuone.jpg

Actually your work is ooh-aah worthy.

It's not much of a suggestion but more for confirmation. I have Varga Ti Arc backpack. It is made from 70D ripstop nylon, which I believe is equivalent to 1.9oz. This is an external frame backpack so that might change things a bit in how it carries, but at least you know the fabric can be used.

Thanks, that's exactly the sort of info I need. I've used 1.9oz (70d) ripstop in two packs, for the front and side panels, but neither pack has seen a lot of use.

I hadn't seen the Vargo pack before. As someone who started with an external frame pack, I know they have some advantages (and some disadvantages, too.) I always thought that the evolution of the external frame was incomplete, but of course internal frame packs took over the market.

In the old days, manufacturers made a big deal about the strength of the frame, usually using 1" diameter aluminum tubing, although a few used 3/4" (notably Trailwise and Jansport). I think 1/2" aluminum would be strong enough, especially with the lighter loads people carry now. Titanium is lighter and stronger, but expensive.

I read a few reviews of the Vargo pack, and people seem to love them, but all mention the same things they'd like changed, like the top design. I'm guessing maybe they've designed it without benefit of someone on the design team who has experience with external frame packs. People certainly rave about the comfort, though.

I wish I had the metalworking skills (and a shop) to experiment with this. The traditional external frame pack updated with lighter materials and a few tweaks might be a winner.

I've made a few external frames and adapted them to commercial packs. Even my day pack has an external frame and I love how it works for me.

Check out the new external frames from Varga. They've addressed some of the criticisms.

It's a misconception that ti is lighter than al. The reason products made of ti are typically lighter, is that it's stronger, and you can use less of it (i.e. thinner wall tubing). If the dimensions were identical, the ti would be heavier.

That looks great Bill! I would have sworn it was a commercially made pack! But you are right, it is heavy, and that will be almost totally down to the use of Cordura...The easiest way to lighten the design is to use lighter materials, that are just as strong as Cordura, in it's construction. The obvious one to mention these days is DCM (Dyneema Composite Material, formally Cuben Fiber). Is has the highest strength to weight of any material out there (Dyneema is 15 times stronger than steel by weight) and it has extremely high water resistance (15000 mm head!) and it is also one of the lightest materials available. Companies like Zpacks and ULE (Ultralight Mountain Equipment) use it extensively in their backpacks, producing some of the lightest yet most durable packs around...Obviously it's not as cheap as other materials, but to make a backpack with it you wouldn't need to buy a whole lot of it, so it wont necessarily break the bank. Zpacks sell DCM material on it's own in various fabric weights. Failing that, ripstop Sil-Nylon would be the next lightest material, but it cannot match Polyester for strength, UV resistance or water resistance. Using a medium weight Polyester material, rather than a heavy weight one like Cordura would be the simplest and cheapest way to lighten your design...As always, it depends on how much you are willing to spend.

That's right, Aluminium is 50% lighter than steel, but Titanium is only 40% lighter. However, even when specially alloyed with other metals and heat treated, Aluminium has only only 50% the strength of steel, whereas Titanium easily matches steel for strength. Accidentally drop an Aluminium pot onto a hard surface, like onto a tarmac road, and it will either dent it or it will have noticeable scratches. Do the same with a Titanium pot and there probably won't be a single mark on it. I found this out first hand! Unlike Aluminium, Titanium is completely non-toxic, and far more corrosion resistant too, plus it doesn't hold heat for very long, so you are less likely to get accidentally burned when using Ti pots. So yes, Titanium may be more expensive, but it's worth every penny!

Thanks. This kind of design, V-stays, etc., seems to work well for me. I wouldn't characterize it as "heavy" though, since it weighs about the same as a ULA Circuit, and the lighter one (not shown in the picture, but similar design) is even less. Certainly not down in the Zpacks category, though.

I've never used Cuben fiber. It's pretty expensive, and I'm frankly not sure it's worth it for a backpack.

You said that the weight would be "almost totally down to the use of Cordura." Well, not really. The back panel made of 330d Cordura weighs about 1.5 ounces, and the pack bottom is slightly less. The Cordura weighs 5.73oz/sq.yd. There are a few other small pieces, so probably less than 4oz total.

Nevertheless, I've been considering some lighter materials. The problem is that the Cordura needs only very minimal reinforcing in the areas where the shoulder straps attach and none where the hipbelt attaches. Any weight gain from using lighter material is eaten up by the necessary reinforcement fabric. Using 210d Oxford for the back panel saves about half an ounce. I'm trying to use what I already have, if that's not already obvious.

I guess I have time to think about it...I made a rookie mistake on the shoulder straps and have to redo them.