Ultra-Light External Frame Pack

[Bill Fornshell]

I loaned my 2.10oz pack bag to someone to look at and haven’t gotten it back yet. So I haven’t had a pack bag for my latest frame. I am making another pack bag out of the Cuben Material today so I can continue to test the frame. I don’t go shirtless in the sun but the ThermoPlastic Material is made to be next to your skin as used in its Medical appliaction. It is soft enough, not soft like down but smooth so as not to scratch your skin.

We had our first day of 100 degrees F yesterday so I have the weather for a good test of how cool this idea is. Cool in more than one way.

[tom jarosch]

This is a very interesting article. Thanks much.
I have a medical problem of a different nature thanyou went through. I have essentially lost three disks in my lumbar region so I cannot carry heavy loads on my shoulders. I have a Stephenson tent and sleeping bag for light weight, but am looking for a pack. I canoe mostly so that adds to the weight, partially solved by a small Kevlar Canoe. I need to shift as much weight as possible onto my hips, so the shoulders get the canoe. Your pack may be my answer. Are you marketing it? Are you looking for a Beta test person? Or do you ( or others ) have other suggestions on packs or sources of medical/backpacking advice? I am just now getting back into the woods after a long hiatus due to back. Thanks. Tom

[Bill Fornshell]

Hi Tom, I am not sure if you are interested in a pack bag or an external frame w/pack bag. I have no background in medicine so I am not familiar with your back problem. The frames like I make are very easy to build. If you have a few tools you may be able to make what you need. I don’t sell anything I make.

I am sure there is a way to design a frame that did not rely on shoulders for support. The frame may look strange but who cares if it works. It also may not be as light as the frames I have been making and may be in the 2 pound range or so.

If you make a frame and are looking for a really light pack bag you might start with the G6 at about 3.7oz.

[Glen Van Peski]

Bill –

Someone forwarded this link to me when I was talking about moisture management. It is a beautiful thing to watch an inventive mind at work! Incredible stuff you have come up with!

–Glen Van Peski

[Bill Fornshell]

Hi Glenn, I am honored by your comments. I hope you noticed one of your G6 packs hanging on my frame.

Your level of craftsmanship is the standard I work to achieve.

You may not recall but I emailed you a couple of years ago about making pack bags for my 1st generation light frame. You said you were to busy but had a new pack coming out that might work. You also were kind enough to tell me where you were getting the Blue material for your packs and maybe I could try and make my own. I was able to get about 10 yards. I still have it. I had to learn how to sew.

Today I am working with very light Cuben Fiber. My prototype pack bag is a little larger than your G6 and I put mesh pockets on the sides and a full mesh pocket on the front. It is 6.5″ by 12″ x 23.5 +10″ roll top collar. It weighs 2.10oz. Interesting note, the mesh pockets makeup 1.28oz of that 2.10oz total. This pack bag needs to work for an AT Thru-Hike so I need something a little larger than the G6 and I wanted mesh pockets.

I have a second prototype pack bag started using the Cuben fiber but stopped till I finish my current light frame. This frame will have the shoulder straps attached to the frame. This way I can interchange pack bags of different sizes. The shoulder straps use the Thermo Plastic with perforated foam under it. There may be a better answer for the shoulder straps but the material I want to try is controlled 100% by Jansports. It seems the only way I will be able to get some is to buy a new product with it or find a used pack with it and cannibalize the straps. I am looking for a used pack.

I enjoyed reading your latest trip report and have exchanged an email with Mike about it. He was nice enough to answer a few questions about some of the gear you both used.

Thanks.

[Robert Miller]

Bill,

I ran across this thread and thought I’d share another “wing” frame design from the past.

I remember my father being so impressed with it he placed his order on the spot, at an outdoor expo in Eagle Rock CA in ’67 or ’68. At the time Andy Drolinger (founder of A16) was making them in his garage. I believe they called it the “hip hugger”. A16 credits another you may have heard of for the idea:

Who was that teenage Explorer scout hanging around the factory at Adventure 16 back in the ’60s, tinkering with the belt systems on external frame packs? None other than Wayne Gregory, the second employee hired by Adventure 16. Today he’s the master pack designer and mind behind the popular Gregory Palisade backpack.

excerpted from almost 1/2 way down here.

IIRC the wings were made of ~1/2″ aluminum tube and they did not pivot side to side like Jansports or your design.

Once I grew up I carried it a couple of times and it was magnitudes better than the Kelty I normally carried.

Fond memories…
Robert

[Bill Fornshell]

Robert, Thanks for the information. I tried to click on the picture but it just took my to the “Join PhotoBucket” Home page. Is there a way you can check the link? I would like to see a closeup of the wing area if possible.

I agree that the “Wing” idea was a really good one and the old Jansport carries really nice. It is just really heavy. The friend of mine who owns the Jansport is a big time fisherman and love that pack.
He uses it a lot to carry his fishing gear and poles from his car about a mile to the beach where he fishes from.

I talked to Skip Yowell last June-05 about those old series D2-D3 and D5 packs. He and his brother started Jansport and he is still active in the company. I told him what I was doing (ultralight) and what a great idea I thought the Wing thing was. I told him I thought they should bring the idea back using Titanium and other lighter material. He did say that Jansport was having there 40th year ( I think it was 40) anniversaty this year or next and would have a few new things for it. I asked if they would be light packs and he said something like not as light as I might want. He was interested in my use of ThermoPlastic and ask how I was using it.
I talked to him twice, he called me once. He was very nice and seemed to enjoy talking about the old days. I think he must be in his 70’s or early 80″s.

My plans are to replace the Aluminum wings with Titanium and reduce the amount of the ThermoPlastic pillows and see if I can bring the weight down somemore. I really like the support and comfort a frame of some type gives me. By using my frame I can hang any size pack bag I might need for what ever season I am hiking. A larger bag for winter and a smaller bag for warmer weather or anything in between.

[Robert Miller]

Bill,

I’m sorry I intended to resize the pic and forgot. Hit the refresh button on your browser to insure you have the revised version. The picture isn’t very clear, and it’s the only one I’ve found, so I’ll do my best to describe it.

The two wings projected ~8-9″ forward of the main frame tubes. The two attachment points were ~9-10″ apart. The upper and lower attachment points were just holes in the main tubes. The tube forming each wing extended through the holes and were joined to the opposite side wing at the centerline of the frame thus forming the two lowest rungs of the frame where a sleeping bag would be lashed. I hope you can visualize my description.

Robert

[Bill Fornshell]

Robert, Thanks. Your description is good and with the larger picture I think I can tell how it was made. One of the nice thinks you can do with the heavier aluminum tubing.

Today they depend on a heavier hip belt and a lot of them now have thermoplastic in them to help support the weight of the pack. One of these days they might just get it right and discover how to do it lighter.

I am going to add this pack to my “Hunt for” items list.

Thanks

[BPL Subscriber]

I am intrigued by what you’ve done with the CF arrow shafts, aluminum, and expanded thermoplastic, and have some speculations as to how to improve the frame while adding lightness.

How about either substituting carbon fiber sheet for the aluminum wings on your version that combines CF arrow shafts with expanded thermoplastic, or using completely custom laid-up CF wings? With sheet, I’m imagining laying up a slip sleeve onto end of an off-the-shelf CF sheet. With either the sheet or the layup, the anti-frame end of the wing would terminate at the hips with a CF layup contoured onto a mold of your own personal hips, perhaps using hardware store expanding insulation foam as a casting material to make a female then male mold of your hip area. With the foam, I think the molding could reasonably be done while you were standing so your body would be close to hiking posture and shape. Similar molds and layups could be used to create pads for the other places you’d want the pack to ride, perhaps forming a semi-circle around the back, to be joined at the front either by a fabric belt or, by extending curled wingtips forwards from the abdomen slightly to remove pressure from the center of the abdomen, by a simple cord between wingtips. An upper back pad and shoulder “straps” could be done similarly. The layups would then be drilled to improve ventilation, or could alternatively be laid up with CF cloth strips in a holey grid pattern after building up a raised grid pattern in molding material on the male mold that would form the holes in the layup.

Similarly, I wonder if the square-section aluminum might for the sake of lightness be better replaced with more CF arrow shafts with sleeves bonded to their tips to allow a sliding mate with the other arrow shafts in any areas where it may be desirable to avoid bonding one arrow shaft directly to another to allow disassembly.

I wonder how you have prevented the aluminum crosspieces from sliding on the arrowshafts…can’t tell from the pictures.

I’m not sure you documented the source of your arrow shafts, but think I saw a CF sheet source somewhere on the DIY section of this website. I hope the BPL staff will be creating a references section for materials for your and other projects.

I have a little experience with perforated thermoplastic in a night wrist brace application, and the material used for that has fatigue problems in that application…areas that get much flex chunk off after a while without a lot of warning. I’ve repaired mine as parts fail with epoxy-saturated strips of ankle-taping cloth tape. So I wonder how the material in your vented parts is holding up. My material predates yours slightly, however, so they may have improved what they use for wrist braces; I do remember that that technician chose the heaviest grade they had for my wrist brace. The wrist brace application seems to call for more durability under long term flexing than the head-positioning apparatus, so I’d think the good materials would work their way to wrist braces, but it may be that somehow more durable materials got to head-positioning first.

I also have one of the Stephensons, incidentally. Thanks for your development work and for sharing it so freely. I hope it inspires lots of similar developers to this site and that the staff efforts will take off.

[Bill Fornshell]

To BobOne:
Hi, Thanks for your interest, comments and sharing your ideas.

You post comes at an interesting time. I received some material last week that I maybe able to use with my Thermo Plastic frames. I have 5 different frames hanging in my workshop that are made to use the Thermo Plastic “pillows” as I have started to call them. The frames to most would seem a little weird. They even seem a little weird to me at times. They are mostly made for different weight “Pack Loads” from very light to 50 pounds or so.

My last one is a Mountain Hardware Exodus style, more or less much lighter clone. There are parts of the that frame that I like a lot and used some of their ideas and but with lighter materials. Their frame is about 4 pounds and for me that is really heavy.

The big question I keep coming back to is how heavy a pack do I expect to have to carry. This weight would be on “day one” after a resupply and what ever amount of water I might need for the season/area. I consider myself a ultra-light to SUL to Hyper-light backpacker and not one to carry much extra stuff. Enough for the season and some degree of comfort but not many extras. My standard pack load would be something for a warm weather AT area hike. The length of the hike isn’t important to me as I look at most hikes as a 3 to 5 day period and then a resupply. With this type of thinking even an AT Thru-Hike is just a bunch of 3 to 5 day walks. My full-up pack weight might go 9 to 14 pounds in warmer weather. I would expect somewhat more in colder weather maybe 30 pounds. I am working on a set of gear for a cold weather AT Hike and don’t have a good estimate of a top end weight yet.

Q-1. I am intrigued by what you’ve done with the CF arrow shafts, aluminum, and expanded thermoplastic, and have some speculations as to how to improve the frame while adding lightness.

A-1. The Carbon Fiber tubes are from FIBRAPLEX and are not arrow shafts. I do use arrows shafts but most have been Easton Aluminum Arrows.

Q-2. How about either substituting carbon fiber sheet for the aluminum wings on your version that combines CF arrow shafts with expanded thermoplastic, or using completely custom laid-up CF wings?

A-2. I agree that Carbon Fiber in some form is a good answer. I have looked into Carbon Fiber sheet material. It is very light and should be very strong but it comes at a high cost. I have also asked a place here in town that does custom laid-up Carbon Fiber work but decided that cost also was to high. I am not selling anything so when you do all that work for one or two pack frames it isn’t very cost effect. I expect one day I will make a new set of “wings” out of some of my thin (.016″) Titanium. You might say that Titanium isn’t cheap, no it isn’t, but I know how to work it and have the tools necessary.

Q-3. With either the sheet or the layup, the anti-frame end of the wing would terminate at the hips with a CF layup contoured onto a mold of your own personal hips, perhaps using hardware store expanding insulation foam as a casting material to make a female then male mold of your hip area.

A-3. As a clay artist of many years I spent a few years making a lot of plaster molds to include full body casts. It is possible to plaster cast sections of the body in a standing position so making the mold you speak of should be possible by several different methods.

Q-4. Similarly, I wonder if the square-section aluminum might for the sake of lightness be better replaced with more CF arrow shafts with sleeves bonded to their tips to allow a sliding mate with the other arrow shafts in any areas where it may be desirable to avoid bonding one arrow shaft directly to another to allow disassembly.

A-4. Again I am not using Carbon Fiber arrow shafts but I have looked for square section Aluminum. What I can get here in town in small amounts was not lighter and to special order lighter stuff would cost more than it was worth to me. The Easton arrow shafts I use come in sizes that let me slide one size over another size. My home-made arrow shaft trekking poles are a good example of that. I also have done that on a couple of my pack frames.

Q-5. I wonder how you have prevented the aluminum crosspieces from sliding on the arrowshafts…can’t tell from the pictures.

A-5. I have used a piece of larger arrow shaft over a smaller piece as a sleeve or spacer to keep the cross pieces in place on a couple of my frames. I also use a fitting like a bushing with a set screw in it and put it on the arrow shaft and just below the cross piece. The bushing doesn’t work as well as the arrow shaft spacer. The bushings do show up in at least two pictures if you know what and where to look. In one picture you can see the round top of the white nylon set screw.

Q-6. I have a little experience with perforated thermoplastic in a night wrist brace application, and the material used for that has fatigue problems in that application…..

A-6. The engineer and my Doctor at the Cancer Center where I was treated were a big help in getting me (free) my first big bunch of Thermo Plastic to play with. The engineer did tell me that if I ever bought any not to buy what was made in China. They had problems with it. The stuff they were using now came from France but cost a little more. I have talked or emailed answers to at least 2 pack companies that are or were looking at Thermo Plastic to use someway. I believe Thermo Plastic is what Osprey is using in there hip belt that is put in a small oven and then put on the person to form to them when buying the pack. It is nice stuff but also isn’t cheap. I did buy two sheets (2′ by 3′).

Q-7. I also have one of the Stephensons, incidentally.

Q-7. I am sure you will not want to get rid of your Stephensons Pack/Frame?? but if you ever should I can provide it with a very good home.

If you want to conduct a less public discussion about this subject I can list my email for you.

[BPL Subscriber]

To BobOne:
Hi, Thanks for your interest, comments and sharing your ideas.

You post comes at an interesting time. I received some material last week that I maybe able to use with my Thermo Plastic frames. I have 5 different frames hanging in my workshop that are made to use the Thermo Plastic “pillows” as I have started to call them. The frames to most would seem a little weird. They even seem a little weird to me at times. They are mostly made for different weight “Pack Loads” from very light to 50 pounds or so.

My last one is a Mountain Hardware Exodus style, more or less much lighter clone. There are parts of the that frame that I like a lot and used some of their ideas and but with lighter materials. Their frame is about 4 pounds and for me that is really heavy.

The big question I keep coming back to is how heavy a pack do I expect to have to carry. This weight would be on “day one” after a resupply and what ever amount of water I might need for the season/area. I consider myself a ultra-light to SUL to Hyper-light backpacker and not one to carry much extra stuff. Enough for the season and some degree of comfort but not many extras. My standard pack load would be something for a warm weather AT area hike. The length of the hike isn’t important to me as I look at most hikes as a 3 to 5 day period and then a resupply. With this type of thinking even an AT Thru-Hike is just a bunch of 3 to 5 day walks. My full-up pack weight might go 9 to 14 pounds in warmer weather. I would expect somewhat more in colder weather maybe 30 pounds. I am working on a set of gear for a cold weather AT Hike and don’t have a good estimate of a top end weight yet.

Q-1. I am intrigued by what you’ve done with the CF arrow shafts, aluminum, and expanded thermoplastic, and have some speculations as to how to improve the frame while adding lightness.

A-1. The Carbon Fiber tubes are from FIBRAPLEX and are not arrow shafts. I do use arrows shafts but most have been Easton Aluminum Arrows.

Q-2. How about either substituting carbon fiber sheet for the aluminum wings on your version that combines CF arrow shafts with expanded thermoplastic, or using completely custom laid-up CF wings?

A-2. I agree that Carbon Fiber in some form is a good answer. I have looked into Carbon Fiber sheet material. It is very light and should be very strong but it comes at a high cost. I have also asked a place here in town that does custom laid-up Carbon Fiber work but decided that cost also was to high. I am not selling anything so when you do all that work for one or two pack frames it isn’t very cost effect. I expect one day I will make a new set of “wings” out of some of my thin (.016″) Titanium. You might say that Titanium isn’t cheap, no it isn’t, but I know how to work it and have the tools necessary.

Q-3. With either the sheet or the layup, the anti-frame end of the wing would terminate at the hips with a CF layup contoured onto a mold of your own personal hips, perhaps using hardware store expanding insulation foam as a casting material to make a female then male mold of your hip area.

A-3. As a clay artist of many years I spent a few years making a lot of plaster molds to include full body casts. It is possible to plaster cast sections of the body in a standing position so making the mold you speak of should be possible by several different methods.

Q-4. Similarly, I wonder if the square-section aluminum might for the sake of lightness be better replaced with more CF arrow shafts with sleeves bonded to their tips to allow a sliding mate with the other arrow shafts in any areas where it may be desirable to avoid bonding one arrow shaft directly to another to allow disassembly.

A-4. Again I am not using Carbon Fiber arrow shafts but I have looked for square section Aluminum. What I can get here in town in small amounts was not lighter and to special order lighter stuff would cost more than it was worth to me. The Easton arrow shafts I use come in sizes that let me slide one size over another size. My home-made arrow shaft trekking poles are a good example of that. I also have done that on a couple of my pack frames.

Q-5. I wonder how you have prevented the aluminum crosspieces from sliding on the arrowshafts…can’t tell from the pictures.

A-5. I have used a piece of larger arrow shaft over a smaller piece as a sleeve or spacer to keep the cross pieces in place on a couple of my frames. I also use a fitting like a bushing with a set screw in it and put it on the arrow shaft and just below the cross piece. The bushing doesn’t work as well as the arrow shaft spacer. The bushings do show up in at least two pictures if you know what and where to look. In one picture you can see the round top of the white nylon set screw.

Q-6. I have a little experience with perforated thermoplastic in a night wrist brace application, and the material used for that has fatigue problems in that application…..

A-6. The engineer and my Doctor at the Cancer Center where I was treated were a big help in getting me (free) my first big bunch of Thermo Plastic to play with. The engineer did tell me that if I ever bought any not to buy what was made in China. They had problems with it. The stuff they were using now came from France but cost a little more. I have talked or emailed answers to at least 2 pack companies that are or were looking at Thermo Plastic to use someway. I believe Thermo Plastic is what Osprey is using in there hip belt that is put in a small oven and then put on the person to form to them when buying the pack. It is nice stuff but also isn’t cheap. I did buy two sheets (2′ by 3′).

Q-7. I also have one of the Stephensons, incidentally.

Q-7. I am sure you will not want to get rid of your Stephensons Pack/Frame?? but if you ever should I can provide it with a very good home.

If you want to conduct a less public discussion about this subject I can list my email for you.

==========

Thanks, Bill. It would be good to have the email capability, although I don’t have anything to guard about backpack designs or materials.

My interest is in improving the breed, and I hope to do more hiking again in the future. I like the idea of longer unsupported jaunts and lower base weight helps with that, of course. As does an external frame pack that will deal well with a heavy starting weight with weeks of food, but still carry well at lower loads. I’m also looking forward to expanding my technological payload as we move into the mobile computing/Internet era and come closer to working out the electrical power problems.

I’ll probably keep the Stephenson until I get something I like better sorted out, and I’ll have to get a lot of time away from other projects before that happens and I’m convinced that everything is better, so at least for now I’ll hang onto it.

Not to worry about frame “weirdness”. Most anything new is weird, and without new stuff we would not have much good stuff.

I think you might enjoy getting into CF fabrication. It’s not all that difficult, but would take experimentation if the idea is to get the strongest, lightest component for a given application due to the possibilities of fiber orientation and easily variable shape. My father, some time after his retirement, built several aircraft with fiberglass weaves and epoxy and polyester resins, and he’s not as patient or meticulous a craftsman as you are despite his engineering accomplishments. Aircraft Spruce and Specialty is a good place to get started (www.aircraftspruce.com). I long for the days when it was easier to walk into stores and browse for materials to play with, but there’s an awful lot out there on the web too. Your experience with plastic arts would seem to make it substantially easier than for some and you seem to have the patience and meticulousness that is the primary requirement for neat layups. In some ways, it’s not as satisfying as working metal, but the light parts make it worth it when weight matters and with enough work a satisfying finish level can be had that makes them enough fun to handle. All the fabrication shops charge an arm and a leg, I suppose that is because there is a lot of labor involved, and some material wastage; the materials are not cheap, but in the sizes we’re talking about, probably not prohibitive…but paying somebody else to do the experiments would be expensive while you can do it yourself. There’s also a labor shortage as these materials came to market largely after the schools abandoned manual skills and kids don’t grow up playing with materials the way they used to, and the U.S.-immigrant labor mostly doesn’t have experience with it either. Not too much tooling involved…off the top of my head, if you want to vacuum bag layups, which is nice, the vacuum pump is the biggest expense, especially with DIY vacuum bags around now. There are various power tools that help in shaping and smoothing cured layups that can add up a bit but it shouldn’t take too much for the parts we’re talking about. A decent rotary tool and a power file would be nice; neither needs to be very expensive. If I had more time to spend in the shop I’d definitely be doing more work with these materials.

I think the CF sheet price could come down a bit if more demand develops. It was hard to find anyone selling fabricated sheets until recently, and I think the market is still undeveloped. Once there was enough market to allow some larger runs, the labor content could be reduced enough to lower the price, I would think, and this could also be done overseas. I suspect that many of the people who would use prefab carbon fiber sheet haven’t yet figured out where to get any, such that there is latent demand. There are various statements afloat about a short supply and high prices on CF base materials at the moment, though.

A more durable expanded thermoplastic that will work at low temperatures like this body-cast material does seem attractive. I wonder if the weight of some of the parts could be reduced by trimming them down more to their contact surfaces with the body, then providing tailored mounts, or are you relying on some flex in the cylindrical shapes for cushioning? A tough-enough thermoplastic certainly seems possible but would not be quite a light as a CF layup.

I’m not sure where I got the CF arrow shaft confusion, but I went on a BPL reading binge after getting a membership in the last couple days, quickly ran out of actual member content (hope they get more quickly) and got lost in the forums, which don’t seem that active right now (maybe due to the season?). So I posted with increased fatigue and from memory of a lot of threads at once that was all rather unclear.

Are you using square sections in the frame to simplify joining? I wonder about using larger composite tubing with drilled holes, although that’ s not the strongest way with that sort of material…but I wonder whether it might suffice in this application. But even if that doesn’t work, I suspect it would be worth it in weight to develop a joining method for CF tubes…I looked around on the web a couple of years ago but didn’t find much work in this area, but someone must have done it as it’s would be too useful, and maybe it’s on the web by now. Wrapping and bonding is an obvious way but might tend toward a hand-hewn appearance; a disassemblable joint would seem to be possible too. Another way would be to build flanges by joining a pair of short outer sleeves for each joint that would then slide over the main CF tubes either to be bonded on or perhaps to use something removable like an arrow shaft spacer. I’d think that set screws on CF tubes might lead to early tube failure but again by sufficiently understressing materials it might be possible to get away with methods that might not be optimal if we could build everything we wanted easily.

I’m just thrilled and inspired that you’re doing all this and hope I’ll get enough time to do more one along these lines one of these days. Oh, by the way, I was looking at the luxurylite cots last night, and wondered if you might have considered experimenting with ways to make a lighter cot? It appears to my eye that some unneeded weight is tied up in the polycarbonate legs (substitute triangulated CF-shaft structures or a Ti or CF version of his legs?) and that CF might work as a substitute for his aluminum crosspieces for further lightness. Also, it appears that he stresses the hammock top against the aluminum crosspieces which get substantial flexion, where my initial estimation would be that less material strength would be required if he used the crosspieces as a fulcrum to tension the hammock top against some spectra lines near the opposite (ground) end of the legs and thus used the crosspieces more in compression. I suspect that substantial weight could be removed with those methods.

[BPL Subscriber]

Oops…sorry for repeating a prior post…in improvising a way around the small message-posting window I neglected to trim Bill’s post out when I re-copied to the message window.

[Bill Fornshell]

BobOne:

As I worked through your reply I keep asking myself what you wanted in a pack. Weight of your pack load etc. As my pack weigh has gone down my frame requirement has also changed. I have made several frames for a couple of different gear weight needs.

My interest in the External Frame goes back many years to my first few years in the US Army. As an Infantryman I went from carrying all my gear in a small butt pack with stuff hanging everywhere to the early Army Rucksack and External Frame. It didn’t take long to see the many benefits of a frame that pushed a little away from my back. It was so much cooler than when everything was pushed against my back. I used some combination of the Army Rucksack Frame and the different sized packs made for it. My first commercial external frame was an old Kelty External Frame/Pack. The problem with that pack was that it also more or less pressed against my back. The best internal frame packs of the day also did this. Most hikers just put up with this.

A few years ago I started trying to make a very light external frame that would push back from my back and be cooler in warm weather. My lightest frame was one made of Titanium and Carbon Fiber Tubes. It was just about the same size as the Army External Frame I had. My lightest frame weighed under 7oz. The same size frame but using aluminum in place of Titanium only weighed just under 9oz. The cost and trouble of working with Titanium was not worth only a 2oz weight savings.

With the Titanium frame I started playing with a breathable shoulder strap and hip belt. You can see pictures of my first effort at the beginning of this thread. I used a couple different size woofel balls mounted where they would push the pack frame away from my back. My first walk with the woofel ball pack worked so well I knew I was on the right track. The woofel balls would never be the answer but I satisfied myself that the idea would work.

I thought the idea of an air space between your back and your pack would be a popular idea. It would let all those expensive jackets with high tech material really wick moisture away from your back. The marketing down side was that with this type of frame cheap material would work also just as well. Well, the marketing of the internal frame and sleeping pad supported packs were to entrenched. Some pack makers have come with new stuff using terms such as wicking and moisture management of their new packs but they really don’t do that much yet.

I started playing with Thermo Plastic during the end of 2004. Making forms for the Thermo Plastic was easy for me and as I played more with the material I learned a lot about it. My goal at first was to use the Thermo Plastic like little pillows between my body and the pack frame, shoulder straps and hip belt. I was using a lot of the Thermo Plastic and the weight of the packs were coming up. I had to step back and rethink what I really wanted and started working on new designs and looking for new material.

This is when I had a closer look at composites. I talked to several people here that work with composites and one was willing to let me watch him work. He was doing the Vacuum bag method and thought that was how I might want to make my parts. I decided that for one or two frames it just wasn’t worth the time to learn how and then get the necessary tools and materials. I even thought about a small production run of 50 or so frames but decided that still was to much to get into just for a couple of pack frame for myself.

I do believe a very light molded composite external frame or hybrid is the way to go. I made some drawing and a couple of paper models. Making full size models for molds would be easy to do with the type of material I used for my plaster molds. I just don’t think there is any real reason for me to do much more work or thought on composites. I can achieve a frame weight I can live with using the material I now work with. I save the start-up cost of learning how to work with composites, the costs of new tools and materials. I would never recover that cost unless I wanted to try and sell frames if I came up with something that worked. That would require a larger investment and I have no interest in going there.

I did have a long look at the Aircraft Spruce site. There was a time when I was doing some flying and had a little over 100 hours in a Helicopter. There was a kit for a home-made helicopter called the Scorpion I think. It was a one person and I thought about making one. There was some kind of problem with it and the first run was delayed for some reason. I lost contact with the company and let that idea drop.

My Thermo Plastic works at 150 degrees F. It can also be recycled a time or two. All my CF tubing or arrow shafts are round. I can join my CF tubes to each other or to the other materials on my frames. I think I have pictures of how I do this on the thread for my home made trekking pole/tripod.

I have to say that I have never considered the Luxurylite frame or other items anything I would ever use. I talked to ??? name ?? several years ago before he reduced his prices. I never really understood the design but I know some folks that have used the frame setup and like it. The LL cot was also something I never really looked at as I like and use a very light weight hammock.

[BPL Subscriber]

Bill, my pack weight is in re-evolution as I’m entering a gear-replacement cycle, which is why I subscribed here. I was using a poncho tarp and top-bag with shredded-foam bottom and mummies used as top bags in the seventies and went to a smallish “two person” single-walled tent in the eighties, but tend to tarp and am looking more towards the UL/SUL stuff now for shelter. My clothes are already fairly light for warmer environments but I moved away from puffy insulation in my technical gear a long time ago so as temperatures drop I fall into only the “Light” category here; that’s something I mean to solve but I can get more out of sleeping and shelter revisions, I think. I tend to go without cooking in most temperatures that I commonly get into. The Stephenson pack is not very light for right now but I’d call that the primary longer-voyage (the frame at least, maybe not the Stephenson bags, which I could probably lighten relatively easily with current materials) pack for now if I get going with solid treks again. I’ve preferred an external frame pack with loads for more than a weekend since the sixties except to the extent the external frames slosh around too much, which better technology can help. External/internal for me is about coolness and organization and not compressing puffy insulation more than necessary, vs. off-trail sloshiness, mostly, once I’m out for long enough that I’d be carrying a larger internal frame pack to deal with my currently bulky clothing and with food for a longer range. I don’t know what people will buy, but hope that in the Net era, information will spread better and the external frame pack will become more developed and better accepted. For the future, I mean to equip with a non-framed setup for shorter trips along SUL lines, and work from the Stephenson setup towards a lighter external frame for primary applications where I’d be carrying more food and/or water. I’m prone to be willing to carry more weight to avoid seeing people and dealing with re-supply for longer; maybe that sounds curmudgeonly?

So I can’t add it up right now but we’re looking at moving down from maybe something in the 10-12 pound range to something lighter for a base weight in the external framed setup. I mentioned interest in increasing my range, but the higher end of that range is dependent on how my ankle will hold up these days. The longer range and thus food weight becomes the primary determinant (except in desert hiking where the water tends to take over from food) of the high pack weight and could go to say 55-60 pounds starting load if my ankle were to prove completely happy. This gives a pretty nice range with a 10-12 pound base weight but would increase range and comfort with lighter shelter/clothing/sleeping gear, and I’d like to be down more at 6 pounds-ish. My idea was to abandon looking at my individual elements for a while to save time and headaches, and join BPL and start research when I had a little time to set up for a more systematic revision. Indeed, I abandoned most revisions for quite a long time, and I still don’t quite have any free time, but I managed to join BPL. Now, after looking at the member sections, I think that if they stick to the new editorial calendar and double it a few times in subsequent quarters, I might stay around here longer than a year. Haven’t seen the print version yet.

The electronics package doesn’t make sense to carry yet, so I don’t. The technology is sort of almost there. So I don’t consider that part of the load presently, but I’d like to add it in at around 2 pounds and falling without consideration of the unusually long power requirements over business day use…the consequence being that we’re more not there yet on the power than on the other elements. I’d get out more if this were ready.

I agree that composites are the way to go but that it’s possible to proceed quite a long way without making everything out of composites.

It looks like I must have gotten that wrist brace around 2001 so I suspect that the materials may well have improved between when mine appeared and yours did…or I might have gotten the Chinese materials despite acquiring it from an elite sports medicine facility.

External frame packs SHOULD be dominant but development almost ceased when internals caught on; I think a lot of it was about some vicious cycle of advertising images of climbers and what the stores were selling. They were unreasonably popular with trail users as soon as they started to look flashier even in early models that were clearly inferior for trail use to external frames of the era. And Stephenson had a great improvement but the market mostly didn’t notice that his pack existed.

Last I looked it appeared the mini-helicopter kit market is coming back with more offerings. Big commitment, though. I’d have to have a real use for it to want to spend the time.

When I was talking about CF tube joining, I was thinking of solid joints that are around 90 degrees such as where you go presently to square section material but would need to join round tubes if you used round tubes for crosspieces (which could let you substitute in more CF. This is what I Googled around for a couple of years ago without success. I think I must have seen your pole efforts a while ago, perhaps via the Yahoo list, but don’t recall a tripod joint that would be a solid acute angle joint arrangement like I just described so I’ll look for that thread unless you tell me it’s not like that before I can get to it.

My mind is not wrapped around ex-frame bag designs at this point although yours look interesting. I would tend to customize around big water loads and, later, electronics/power. I was set up to carry upwards of 7 gallons on some trips, but I’d prefer not to go quite that high, of course.

I mean to look into hammocks but often am in territory where I’d be surprised they’d make sense (often ranging deserty) so I’ve not had the luxury of considering it as a primary solution and haven’t messed much with one in a few decades. I’m a side sleeper and never found a hammock arrangement that didn’t hurt me, not to say it’s not out there by now. I’m fairly happy with foam and haven’t used much else since the sixties, and at home have mostly slept on the floor or carpet with a little foam for about 25 years, preferring it to beds.

The current lightest LuxuryLite cot is still rather heavy, but close enough to begin intriguing as I can imagine some ways that I think would take it lighter. There wasn’t much cot development for a long time that I was aware of and it seems LuxuryLite created some awareness that they don’t have to be all that heavy so I’m hoping to see more improvements. There are at least a few active backpacking gear tinkerers out there so maybe someone will get on it soon.

[BPL Subscriber]

Oh, BTW, I just had email with Steve Ferrel over at Kite Studio (www.kitebuilder.com) and he says he can do his fittings in aluminum as well as his usual ABS. Ti would be lighter and have better fatigue resistence, but it seems like some judicious overbuilding with the aluminum may cause the stress risers created in the tubing by this simple sort of joint to fail before the fitting.

Several of their fitting configurations look like they might be useful for a backpack frame construction, and being able to buy these off the shelf makes it a lot easier to play with assemblies than coming up with your own joints.

[Bill Fornshell]

This picture shows one of the fittings from kitebuilder. I call it a bushing with a set-screw. I bought 6 or so in two different sizes but had to drill them out a little. kitebuilder has several things that I use and I have talked to Steve a couple of times about other fittings. The one you can see easy is on the center tube and has what looks like a white round screw top.

That frame has been changed some and I removed the center tube. It has four of those bushing/fittings on it. They make adjusting the Thermo Plastic cross piece easy.

I am about to make the next version of a wing frame. I have a new hip belt and shoulder strap design that will go on it and should be a little lighter. I am waiting for some new material and might get it in a day or two.

Getting the right fittings and other little stuff necessary will always be somewhat of a problem for these frames. I talked to Bill Stephenson (the younger) about their old frames and he said they had a problem getting the necessary fittings and stop making the frames.

I also had a chance to talk to Skip Yowell at Jansport about a year ago. I was able to ask him some questions about his “Wing” design and suggested that the time for the “wing” idea in todays lighter material might be ready for a come back. I told him what I was doing with his idea and said it was time for a well designed, really light external frame. He said Jansport was coming out with a couple of new items for there 30th, I think anniversary, this year or next. I might like them but they were not light by what I call light.

[Dale Wambaugh]

Bill said, “He [Skip Yowell] said Jansport was coming out with a couple of new items for there 30th, I think anniversary, this year or next. I might like them but they were not light by what I call light.”

Jansport made some really light packs for the time. I have one that is about 3500ci for the pack bag and there is enough room to strap on at least that much more on the frame extensions, top and bottom. The whole rig is about four pounds.

Compare the Jansport to the welded h-frame competition and you can see their good design. The Jansport tubing is much smaller and thinner and the frame is easily adjusted. The pack, waist belt, and other hardware is light by the same degree.

If the same design were build using titanium tubing and UL concepts and materials were applied to the pack bad itself, the weight would easliy drop over 25%. Trimming down some of the large arcs of tubing on the top and bottom would drop the weight further. A 3 pound pack is easy to imagine and I’m sure something close to 2 pounds is possible.

Those side struts on the Jansports always looked to complex and heavy to me. I understand the engineering advantages, but all that metal and plastic jutting out didn’t appeal to me.

I think a laminated carbon fiber frame could go a long way towards a design using the side strut concept and keep the hardware to a minimum. It is not beyond the resources of a back-yard builder to make an epoxy and carbon fiber frame. Prototype molds are not terribly difficult to make.

I’m thinking of a frame with large openings that looks like a squared-off figure 8 with the bottom wrapping around to form the side struts. The shouler straps could be mounted directly to the frame and a typical mesh back band could cushion the top section. The hip belt would be a full circle and mount on the side struts or another mesh panel could suppport the back with two separate straps for the hip belt. Pad to suit.

If the frame bows too much, it could be stiffened with a couple arcs of carbon fiber. I’ve seen paper tubes used for stiffening-tube molds on fiberglass prototyping and the same could be done with carbon fiber– a half round of thin plastic tubing, etc would form the arc and the cloth is laminated over the top. With a little brainstorming, it may be possible to remove that mold material after the epoxy is dry. The resulting space could be handy for mounting purposes or a spot to put survival items or tent poles.

The pack bag could be mounted on the other side of the frame with fabric straps running through slots machined in the frame material and conventional Delrin fittings. With some fiddling, the pack could be attached with hardware and reinforced panels in the pack bag fabric.

My choice of a pack bag(s) would be Sea-to-Summit silnylon waterproof bags strapped on through slots in the frame. That makes for total customization and eleminates the need for other waterproofing and more layers of fabric. It makes me crazy to buy an UL pack and then add expensive bags to go inside! The bags could be swapped at will and easily replaced if damaged or technology changes. The slot method of mounting actually lightens the frame and uses no hardware other than the straps. And I wouldn’t need to make the bags. Of course, I think we could find someone to make a cuben fiber pack bag :)

[Bill Fornshell]

Hi Dale, Glad to see you jump in here with you thoughts and ideas.

I agree with you on the Jansports packs “for there time” comments. When I talked to Skip Yowell most of my comments were about using titanium and some type of composites. I mentioned I was using some Thermo Plastic in my packs and he did say they were looking into that material. I really enjoyed talking to him and listening to his comments about the early days. I am sure Jansports could come up with a good 3 pound pack if they thought there was money in it.

For the big companies making packs as one of their products I am afraid it is all about the “bottom” line $$.

There are a few pack makers I think might be able to come up with a 2 to 3 pound light external/hybrid external of some type. The first is a company that really jumped into the pack market this year in a big way – Mountain Hardwear. I really want one or both of the different “EXODUS” monsters. I don’t want the packs to use as they are really heavy. I want them to re-engineer and drop their weight down to around 2 pounds. I was about to buy one of the Exodus – Harrier model with this last discount from REI but they were on a sales hold while the hip belts are being replaced. I think I could re-make the frame using lighter material and sew up a new and a little smaller pack bag out of Cuben material and get down to 2 or 3 pounds. 2 pounds would be my goal. I have made a set of shoulder straps a lot like the ones they use and would use a different strap setup on the hip belt. I have had both the “Motive and the Cruiser” models fitted to me and weighed both the bag on and off the frame and the frame alone. I guess I have about 3 hours flight time logged in those two packs. I talked to one of the guys at the MH customer service about those packs till he knows my voice. They are using some type of composites in that pack and if the $$ were there could just add a really light version to the Exodus series. Will they, I would not bet on it.

That leaves GoLite as my next best pick. Coup has said something about looking into the different mylar materials. This I would take to mean Cuben Fiber but there maybe others. It is however one thing to add packs made out of Cuben type material to your pack lineup and another thing to add a light weight external frame to your line up. Cuben packs are not that hard to make.

Then you have several other pack makers such as Ron Monk at Six Moon and the McHale. Both make really well made packs. To heavy for me but well made. Of the two I would bet of Ron Monk as McHale seems to be stuck on “Heavy” and “Old Design”. The McHale packs maybe the BEST out there for large packs and I really like Ryan’s smallish size Summit pack, but I don’t see McHale adding a very light external of some kind to his product line.

The next two companies who could/might be able to pull it off are Gossamer and or ULA. I would expect both to add a Cuben pack to their product line sometime but I don’t think they are up to the development of a light weight external frame/pack bag like we are talking about.

I am sure there some others that I didn’t list who might/could also do this.

Then last, there are the leaches lurking out there ready to steal any good idea they read about or see pictures posted at this MYOG site and others like it. They do very little or NO research and development and just steal ideas and get them into production as fast as they can.

For those that are still reading I want to make one more comment:

Dale, I make all my pack bags to attach easy to my frame and in the same way. Or you might say I make all my frames to hold my pack bags the same way. I can then change out the bags from smaller to larger as the hike requires in a very easy and quick way. I also have started using an attachment system on my pack bags to add different pockets or remove the pockets as I need to carry different sized things on the outside of the pack. That way I only have the extra weight of the outside pockets when I need them. I agree with your last couple of paragraphs that this is the way to go. I also think getting pack bags made out of Cuben will get easier in time. Or you can always just make your own.

[Dale Wambaugh]

I got on the carbon fiber frame kick when one of my co-workers came in with a megabucks bike with a carbon fiber frame. I could easily balance it all on two fingers and one with some pain :)Of course the stuff looks sexy too– a marketing department’s dream.

The frame I have in mind is much like the old WWII plywood pack frames, with larger holes and some reinforcement in the right places to control flexing. The bottom would have the wings/struts to hold the belt. The back band would be much smaller– 6″ or so tall. I’d love to see some sort of twist-to-adjust and lever-to-lock tighteners for the back band. Most of the old back frames use ladder buckles and it is hard to get them nice and tight.

In production, it may be easier to mold long sections of the u-shaped frame and just chop them to length. The struts could be bolted or epoxied on afterwards. That may be a good idea anyway, as they could be replaced if broken and several sizes could be offered. That would allow some vertical adjustment for torso length too. All said, that frame should only be a few ounces.

[BPL Subscriber]

Hi Dale, nice to meet you too.

I’m hoping we’ll find somebody with the right combination of time and skills to jump into backyard carbon fiber to inspire us and create a movement. It’s really not that hard, and the only thing that requires a lot of labor is getting things to look pretty like those high-end bicycles, but that barrier is also surmountable. Some pretty good work can be done without the vacuum pump, which brings the cost of entry down.

Bill, I hope you won’t worry too much about the people who steal designs and bring them to market. I wish they’d compensate the people who develop stuff for their own and community use, but at least if they get something on the market, other firms will have to compete with their probably shoddy implementations and after the market does its magic we’ll all have access to better commercial products as a result. Have you looked into open source licensing modeled after software projects to get some protection for community-developed projects?

Here’s something a I ran across that conceivably help us out: http://sketchup.google.com/ 3D modeling software has tended to be quite expensive, and could help both for our own visualizations and for communicating visual ideas…and now Google has something for free, with a more fully featured version available for some fee.

I haven’t caught up with rapid prototyping (solid 3D realizations from 3D software) in a few years) but I see the price of the machines is coming down, which should make the price of work at service bureaus cheaper too. At some point this will leap to HP making a home machine; the price should come down a whole lot then not only due to economies of scale but because current manufacturers are probably protecting their high-end business by keeping their entry-level machines at $15,000 and above. RP could be a good way to go for a backpack mold. But I like the idea of custom molds for epoxy/CF for the parts that touch the body, and it’s probably easier to do that for now with plaster or such than by scanning, although scanning is also not an impossible hurdle and there might be a service bureau around that would make it simple and cheap. If you look into service prices, be aware that the one-off prices are higher than if you find one that will let you gang your work into a group of other projects and let the turnaround time be a couple weeks or so instead of a day or two. When they put a lot of projects in the machine at once, they can get more out of the machine, so the cost of the output can be lower. This site can help you find service bureaus: http://home.att.net/~castleisland/rm_c.htm

There might be significant yuppie appeal to a CF backpack frame, don’t you think? Maybe someone will jump into this commercially.

[Dale Wambaugh]

“There might be significant yuppie appeal to a CF backpack frame, don’t you think? Maybe someone will jump into this commercially.”

If there is a market for $50 Ti one liter pots, and people will stand in line 20 minutes for the priviledge of buying a $3 cup of coffee, there should be no problem cooking up a marketable CF backpack.

You mentioned vaccum pumps– you could probably rent one. The ones used for refrigeration and air conditioning have plenty of power. I wonder if you could fake it with a column of water– provided you live on the edge of a bluff or other drop:)

Hey– I forgot the water bottle holders molded into the struts.

[BPL Subscriber]

Just quickly on the vacuum issue, the cheap way to fake a vacuum is an aspirator pump that attaches to a sink faucet; they’re quite cheap. You don’t draw as much head and it’s not as fast, but it might work out for smaller vacuum bag layups. I actually have one that I was using for pulling the bubbles out of silicone molding materials for investment casting using a plexiglass vacuum chamber. That chamber probably has over a quart of volume, so maybe it would at least be fast enough for a small vacuum bag layup. I’m not sure it would work out but it would be worth looking into for someone doing small layups.

As I mentioned previously, DIYers brought the price of the vacuum bags down…they used to be pretty pricey.

[Bill Fornshell]

I went back to the Aircraft Spruce site and ordered one of their “Composite Materials Practice Kits”. It comes with a book. I will read over the book and see how to use the stuff and play with it. They have other books and if this one is not enough I will check out some of their other books.

I also looked at the free 3D software program that was mentioned. They don’t have it for the Apple/Mac computer yet. I will check back there from time to time and watch for the Mac version to come out.

I am open to debate on several designs to try and see how they work out. If you have specific ideas post them and when we get ready to model them I will give it a shot.

This needs real imput or it will not work.

We can do this public here or as a closed group someplace else.

[Dale Wambaugh]

For a one-off this small a good dry layup and some weights would do the trick. Vacuum bagging works grea with odd shapes like a canoe or kayak hull.

If I were to make a frame like the WWII plywood frame, flat weights or some sort of big water bladder would give the layup a good squeeze. You can get most of the extra out with a squeegee on something this flat and small– reaching across and covering the whole layup with one stroke of the squeegee wouldn’t be a problem.

You know, with a mold shaped like the WWII plywood unit, it would be easy to make a clamp mold– layup over the postive bold and clamp the negative one right over it. Put the whole works in a jig with a hydraulic auto jack and squeeeeeeeze. A set of pony clamps, ratcheting bands, or even a Spanish windlass could put enough pressure on the mold halves to to a pretty good job.

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