UL Backpack Fram Question

In the packs I have made I use Easton aluminum arrow shafts. (free – rejects from sporting goods store)
I sew tubes to hold the arrows in place with a heavy velcro top flap. The arrows are in a "V" shape, each arrow going from the center of hip belt to reach shoulder strap attach location. I then use a removable z-lite pad in a outer pocket for framing. (like most MYOG packs). My latest pack is using a piece of shipping foam rather than the z-lite. I use a POE AC air mattress so do not need the added weight of a z-lite. My pack weighs in at 24oz, made from Dynema X-grid fabric and will handle up to 35#. I used it on a thru-hike of the JMT this year – worked superbly. At my 7 day resupply (Garcia bear canister and 7 days food, ~16#)I was at 33#.
-Dale

Joslyn,

Here’s what I use.

frame

Daryl

I use 6061 aluminum (round and flat) bought from McMaster Carr–great web source for raw materials

This looks interesting: CiloGear framesheet (one of the packs they’re used in: 45L)

And… a detail video

Another option: Aluminum stay

Unfortunately, I don’t have weights on either option.

Another aluminum stay: 4 oz.

These are some great options! The Cilo gear frame sheet looks the most unique and I'm kind of excited to try it out. Of course as with any MYOG project, I now have ideas for 2-3 packs, so I might have to go ahead and try them all out. :D

Does anyone know how to make an aluminum hooped frame like GG or SMD uses? I thought I read on here that you can buy a tool at harbor freight to bend aluminum rods, but I can't seem to find that thread. I'm wondering how hard that would be to do and how much $$ it would save over buying one from GG for $25 plus shipping.

Harbor Freight Tools has a number of metal bending tools. One is a metal tubing bender. However, I don't see many with a low enough cost to rationalize buying the tool rather than buying parts ready-made. If you wanted to make twenty or thirty frames, that would be different.

–B.G.–

bending tubing is more difficult than bending solid material – tubing collapses

with solid – just bend it with vice or whatever

I went to polesforyou.com and got some aluminum tubing poles. They had a bending jig. Plywood half circle that they bent tube around the outside of. Metal at one end of the half circle to keep the tubing on the edge. Then they just pulled by hand, against the plywood circle to bend the tube. Pulled on it a number of times to bend it. Then they asked me if it was enough. I asked for more so they bent it a little more… Easy to make something like that. I think they had several plywood pieces with different radiuses depending on what was needed.

easiest is likely to buy a prebent stay
Or can buy flat aluminum strip, or rod and bend using a crude tool you can make, couple of dowels in a piece of wood basically.

Tubing bender and cutter is cheap, relatively. You dont have to bend the top sharp bends, you can cut and braze pieces together for that if you want with low temp rod. The back curve bends are easy if the al is soft and you go slow.

I have used a few tricks over the years for bending tubing <1/4" (too small for normal bender.) From filling with sand, to bending with steel cable inside. Both work reasonably well.

One of the best backpacks that I have ever had was purchased thirty years ago from REI. The only stiffening it had was a pair of flat aluminum strips that slid into reinforced pockets on the inside of the pack bag. You could use it that way, with the strips flat, or you could bend them around your knee to get a custom shape.

The 1" flat strips had rounded ends coated in plastic so that they would not tear out of the pockets.

I felt like flat strips were superior to solid rods or hollow rods.

–B.G.–

MLD has a frame on their website made by Klymit.

it can be pumped up very stiff with the pump

Maybe these are a couple of the older threads that you remember that touched on bending aluminum rod and tubing here and here?

Wow, timing. I just got my fabrics&accessories for my next MYOG projects. AND, yesterday I ordered the SMD Aluminium Hoop. Without reading this thread. Stay should arrive next week.
I played with the thought of bending my own hoop out of aluminium tubes but did the math and figured the 25€ are way cheaper than hunting down rods and bending tools, count in the time spent too and it’s an easy choise. (Probably need to count twice the amount of rods too as the first one wouldn’t succeed). Thats the negative, realistic, approach. Although, I miss out on the experience.

To the previous experience. To bend a hollow tube you’ll need a inner part too, for example a spring, to prevent the rod from buckling.

Can comment on the hoop when I get it.

Question. How have others solved the placement of the stays. I’m planning on using tubular webbing for it. Would obviously want to get as much transfer to the hipbelt as possible. So, normally the frame is inside the pack. But how about placing it on the outside. That would allow the frame to be attached directly to the hipbelt. Ah, right, like ula ohm ! (Just came in mind..) Wouldn’t that be the Right way to do it?!

Let’s have some wild crowd sourcing here guys!

You can bend tubing without an internal spring. For that matter, the amount of small diameter steel tubing used for a pack stay wouldn't weigh very much and is readily available in the form of ready made brake lines from your local auto parts store. Steel would be good for prototyping at any rate.

This is the sort of tubing bender you want for stuff up to 3/8" (search on "compound tubing bender):

i have seen bending jigs made of plywood for "one offs". it does require some time to build but might be worth considering.

Not to totally derail this train of thought, but does anyone know where I could just get flat aluminum stays? I think higginssupply.com was once suggested, but I'm not sure if I could order just two stays from them.

Amazon has flat aluminum bar stock in various dimensions.

You can buy aluminum flat stock in many hardware stores and definitely at Home Depot and Lowes. They have tubing too.

… for all of the great feedback.