I'm thinking of copying DJ2's carbon fiber external frame backpack (see the threads "Very Light Pack Frame" and "9.5 ounce external frame backpack" in this listing). As I'm not much of a tailor, I think I want to use an already manufactured set of shoulder straps and waistbelt. Cheap is good, as this is a first attempt. Anybody have a source for this sort of thing, beyond using military surplus ALICE gear?
Here are the straps removed from a Coleman Max. No cutting. It velcro's in place into a set of webbing on the pack body. Maybe not perfect for what you want, being a central mount rather than two separate straps, but pretty cheap.
The nylon barbed plumbing fittings are sold in the plumbing section. Their intended use is for connecting flexible tubing. The tubing is slipped over the barbed ends of the fittings. My favorite is the 1/2" black nylon T. Here's a link:
It would probably work well for a waist belt too. I haven't tried it, however.
You can eliminate shoulder straps completely if you use a front bag. I haven't used shoulder straps for years.
The simplest waist belt would be one made of 2" wide nylon with a 2" wide quick release buckle that adjusts on both ends (you don't have to sew the buckle onto the webbing). Check out the 2" double adjustable side release buckle at this link:
I have been using unpadded waist belts for a couple of years now. If they fit well I don't miss the padding at all. The belt fits me well if I simply cut it in half and sew it back together so the two pieces slope slightly upward from the back center (where the belt would cross my spine).
I think I understand what you are saying here. I need to go out and check on what I can acquire locally, and then start playing with the project.
Have you ever drilled holes in the carbon fiber poles? I'm thinking about tapping holes in the cross pieces for attaching the shoulder straps and putting in the load lifters, but I'm not sure how much that would weaken the stength of the pole.
I don't think the carbon fiber poles will tolerate any holes without losing most of their strength.
An aluminum tubing cross bar will tolerate a lot of holes. I use a thin wall 5/8" od aluminum tube for the top cross bar if I need to drill holes. It slips right over the 1/2" barbed plumbing fittings.
Take a look at the ZPacks Exo pack for a method of attaching shoulder straps without drilling holes in the carbon fiber spars. Here's a link:
#1 Yes, your link is heading toward the nylon Ts I use but you must further select color, type of barb and size. Only the size is crucial. I use the 1/2" Ts.
#2 Yes, Skyshark 400 or something comparable for 30-40 lbs. My wife's pack is using no-name fiberglass tubing but she rarely carries more than about 20 lbs.
#3 Yes I have used the .240 ferrules. Either carbon fiber or fiberglass is fine. I haven't tried the .25od ferrules and probably wouldn't use them. The id of the Skyshark 400s is .244. It is much easier to add a bit more glue than to wittle down a ferrule. You might also be able to just plug the ends with epoxy but I haven't done this so I can't speak from experience.
The small machine screw you see in the top corners of the frame are from McMasterCarr. They are 4-40 size, stainless(18-8), pan head, phillips, 3/4" long with matching nylon insert locking nuts.
The 5/8" buckles sticking out of the top corners are where I attach the front bag to the frame.
The string (100 lb kite string)you see goes from the top corners of the frame to loops on the waist belt. It is cinched tight and holds the frame together.
The back bag has two loops that simply go over the top corners of the frame. Two velcro loops lower down then go around the vertical members of the pack frame. The front and back bags can both be removed from the frame without taking the frame apart.
The two 1/2" wide webs coming from the waist belt attach to my front bag bottom (or to shoulder straps if you use them).
The 1/2" webs coming from the waist belt and the top corners of the frame are run through the T fittings and then knotted. The thickness of the web makes for a nice snug fit for the spar within the nylon Ts.
The 5/8" aluminum top bar makes a good handle to lift the pack. I dimpled the ends a little to encourage it to stay on the nylon T. You could also use a carbon fiber cross top bar and run it inside the T instead of over it.
Thank you. That was very comprehensive, and answered questions I should have asked, but didn't understand well enough to. I think I can do this. I aim to have a parts list together this next week, and then put this together over Christmas and New Years.
Good point on the reinforcement patches. I agree that these are the two main stress points.
Short Answer There are two 2" X 2" patches of adhesive insignia cloth on the inside of the bag at the two attachment points. They are glued and sewn to the fabric. Reliability of this particular combo hasn't been fully tested.
Longer Answer I'm experimenting with various hardware, fabrics and reinforcements to determine how light I can go. So my goal is to work my way down to a bag that self destructs, then to return to the last, lightest one that held up well.
The bag in the photos is made of uncoated, low quality 1.1 ounce ripstop with minimum reinforcements. I've used it for about a month, on a daily basis, carrying up to 30 lbs for distances of about 1/2 mile. It is too early to say whether or not it will hold up for the long haul, however.
Previous bags were made of uncoated, good quality 1.9 ounce ripstop with more reinforcments. For reinforcements I typically would add a 1" X 24" long piece of light nylon webbing running vertically inside the bag under and below each of the main loops from which the bag hangs. I've also experimented with including 1" wide seams in this area. All of these prior experiments have held up well with years of in field testing.
Ordering things from Kitebuilder has been taking a long time. I placed a small order with them almost a month ago and I don't think it has been sent yet. Another person said they have been waiting months for an order to be delivered.