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Concept idea for framed, truly UL pack using bamboo, UHMWPE fabric, cord, etc


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Home Forums Gear Forums Make Your Own Gear Concept idea for framed, truly UL pack using bamboo, UHMWPE fabric, cord, etc

Viewing 16 posts - 26 through 41 (of 41 total)
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  • #3377960
    Anonymous
    Inactive

    Thank you for the feedback Ken.

    #3378592
    Anonymous
    Inactive

    After much deliberation, research, and weighing–i’ve decided to go with a true external frame made out of Al.  Chose Al because it’s probably the most durable for less cost and decent weight.

    I had some interesting ideas of wrapping some carbon arrow shafts (which i could repurpose from the old project) in 1/8th Evazote foam and putting them in the bamboo, and then wrapping the bamboo in some foam (thicker though) to create a super strong and durable composite material (that i could fall full force on and probably not break)…however, the fatal flaw is that bamboo is still bamboo and will at some point start to biodegrade, whereas the Al may eventually fatigue and go down hill in strength, stiffness, etc, but should be serviceable for many, many years.  (course, by then Unobatanium will probably be obtained, and the whole pack will be completely obsolete.  We’ll probably have anti-gravity packs that lighten not just the load, but us too.  Or at the very least, super light, inexpensive, all woven dyneema or spectra fabric packs that are also highly waterproof).

    Anywho, wanted 7075 Al alloy tubes for the frame, but they are surprisingly hard to find for instant purchase and reasonable price (much easier to find other forms of 7075 Al).  The exception would be to order some discounted trekking or ski poles on Sierra Trading Post or the like and repurpose the material. Or maybe Easton poles?

    Course, i had that bright thought in hindsight.  So had already ordered 6061 Al alloy tubes.  I did get a piece of 7075 flat bar for the bottom.  Reason being is that i can contour it much more easily to my shape.  It’s .25″ thick, and 1″ wide.  Hopefully it will keep it’s shape and structure–7075 is suppose to be some pretty strong and stiff stuff for the weight..  I have an idea to to help keep it stiffened by sewing a tight fitting 1 oz cuben/membrane silpoly blend sleeve for it to go in, to help keep it’s shape once it’s been bent.

    Learned some interesting things that i wasn’t aware of.  Apparently grade 2 Ti, aka “pure” Ti has similar strengths to 6061 T6 tempered Al, but a more expensive, but fairly common Ti alloy actually has twice the strengths of 7075 Al alloy, which is considerably stronger than it’s 6061 sibling.

    Yeah looked at that Ti alloy, but at those prices, i might as well be able to afford gold capped teeth also.

    #3378606
    Anonymous
    Inactive

    Another quick update:  Decided i’m still going to do the composite idea, but with Al and CF/foam.  I’m going to wrap the carbon fiber arrow shaft in 1/8th evazote foam + expoxy, and put it in the the Al tube.

    Decided to go with some 7075 alloy Easton tent poles instead of the tubes i mentioned earlier. The Easton poles are nice–besides being 7075 alloy, they are hard anodized/scratch resistant. Normally they’d be a little too thin and too flexible for this purpose, but the CF/foam core will add stiffness and strength.  The combo of the Al and foam should keep the CF from cracking/splintering upon impacts or sudden force/pressure.

    Perhaps overkill, but i really want this thing to be robust and durable.  Not considering fittings, the frame is still only going to weigh around 6 or 7 oz, while being bombproof.  Sure, you probably could get lighter and similar strength, if you went with a full, high quality, expensive molded carbon fiber frame like KUIU uses, but this is at the fraction of the cost.  4 Easton poles were 16 dollars (and 4 oz total), and i already have carbon fiber arrow shafts and foam on hand.

    #3378613
    James Marco
    BPL Member

    @jamesdmarco

    Locale: Finger Lakes

    All good so far, Justin. I believe it is a waste trying to support loads in the 100-150 pound range, though. Have you checked out the Luxury Lite frames?  These are large diameter tubes. Large enough to make joints a simple affair of drilling holes with Al tubing between them. Basically a box with straps, The hook fails to do more than support the load, as do the straps. The shelf is handy for work/tools and doubles as a seat. Well, the seat is too small for actual sitting on, though.

     

    #3378659
    Nick Gatel
    BPL Member

    @ngatel

    Locale: Southern California

    Get one of these.

    You know you want one.

    Miss Kelty and I will be celebrating our 45th anniversary this April. I told her I would like to do a trip in Joshua Tree or the Mojave National Preserve, and if the El Nino rains continue the wildflowers should be outstanding. She said she prefers Anza Borrego, because she knows where the water is and it won’t be as taxing for her because she will have to carry a lot more water in JT or the MNP. She has a point. Plus Anza Borrego is awesome in a good wild flower year.

    She also has made it clear that we will do this trip together, as she has been my faithful companion for 45 years. She puts up with my infidelity with other ladies, but has been firm with me that we WILL be a couple this April.

    Miss Kelty also told me that if I want to do JT or the MNP, I can take that fat b*tch, Miss Serac.

    Miss Kelty has always been jealous of Miss Serac, but points out that she (Miss Kelty) has maintained her svelte figure and always looks sexy versus the big framed Miss Serac. She also reminded me that the best trips I have taken over the past 45 years have been in her company.

    Miss Kelty has been upset for several years about my relationship with the McHale sisters, Miss LBP and Miss Bump. Yes, she admits, they can haul a bunch of stuff, but they don’t have her grace and presence. We often argue about the McHale sisters, and I told her I will not give them up. She calls them the “beasts of burden” because all they can do is carry a lot of weight comfortably. She seems to tolerate the McHale sisters, knowing that I will take her on special trips.

    Miss Kelty doesn’t like Miss Cuben Zero at all. She calls her a frumpy sack, with no shape and tells me that Miss Cuben Zero will fall apart soon. She says Miss Cuben Zero reminds her of Kirstie Alley. Last night she pointed out that Miss Cuben Zero is just dead weight on my shoulders and all that can happen is to be burdened with her, like Bill Clinton has been burdened with Miss Lewinsky.

    #3378783
    Anonymous
    Inactive

    We are in strong agreement on that one James–couldn’t see myself carrying 100 to 150 lbs unless i absolutely had to.

    Yes, i’ve seen those frames/packs. They look interesting and pretty indestructible, but a bit a bit on the heavy side and i’m not sure about the canister storage type system.

    One of the reasons why i do a fair amount of MYOG is because i’m on a definite budget.

    #3378784
    Anonymous
    Inactive

    Hah, i have to say Nick, Mrs. Kelty is still pretty hot, if a bit worn around the edges, after all these years.  Not something one should ask a lady, but how much does she weigh?

    Those McHale sisters…homewreckers, what with their high falutin, uptown, high brow but also coyly charismatic ways and good looks…   Well, some say, flaunt it if you got it, and they certainly got it.

    #3378825
    Nick Gatel
    BPL Member

    @ngatel

    Locale: Southern California

    Justin,

    Miss Kelty is a D4 model, 3/4 length bag, with the “Backpacker” frame and the upgraded wrap around belt. Total weight is 3 lbs 8 ounces.

    Here is a link to my blog with a brochure with all the weights of frames and bags.

    The original Kelty external frame packs are not as heavy as many people perceive, and they are still fine for backpacking. I’m not actually advocating that they are the best option, but I still use them occasionally because they are fun for me. It is easy for me to use the D4 with a total base weight under 10 lbs. But the McHales have been my go to packs for several years now.

     

    #3378974
    Anonymous
    Inactive

    Yeah, that’s not actually that bad all in all.  Thank you for the info and link, Nick.

    #3379135
    Sam Haraldson
    BPL Member

    @sharalds

    Locale: Gallatin Range

    Only 45 years, Nick?  Pff.  Get back to us when you’ve surpassed the golden anniversary ; )  In all seriousness it will be very hard to improve more than a marginal weight savings on the time-tested Kelty aluminum.  That being said, the journey in the workshop or garage attempting to do such a thing can be as much fun as the journey out on the trail.

    #3380680
    Russell Lawson
    BPL Member

    @lawson

    Locale: Olympic Mts.

    Before you spend any hour or money on making something that might break when you don’t want it to.  try a 1/4″ of pex pipe sold at homedepot.  It costs about $3, is very hard to break, can form any shape you want, and flexible, weighting in at 2.5ounces for a full tube.  you could literally just hoop it inside the jam, maybe with some sewn in loops.  This is my pack that I used Pex pipe to create a gap behind my back, wouldn’t ever go back to sweaty back again.

    #3380753
    Anonymous
    Inactive

    Thanks Russel.  I can see how that would help with keeping your back from getting as sweaty, and maybe increasing carrying comfort a little with a little extra weight, but how would it allow one to more comfortably carry 50+ lbs?

    I’m basically looking to create a light weight, workhorse beast that can carry pretty heavy loads if need be, and when not carrying heavy loads, not weigh too much.  All while being extremely durable/long lasting.

    #3380832
    Nick Gatel
    BPL Member

    @ngatel

    Locale: Southern California

    Only 45 years, Nick? Pff. Get back to us when you’ve surpassed the golden anniversary ;

    Kelty had a lot of innovations in his pack designs, but the key to his success was quality construction. He was the pioneer in aluminum pack frames. He contoured his frames and in the early days used a hydrogen gas welder, later moving to TIG welding. Competitors often just brazed their frames, and you would see sad hikers with these packs on the trail with broken frames. I bring this up because Justiin was exploring ways to join frame parts, and he has stated he wants to build a frame that will last a long time and be able to handle heavier loads.

    Justin, you might enjoy Markus Kittner’s history of external frame packs.

     

    #3380842
    James Marco
    BPL Member

    @jamesdmarco

    Locale: Finger Lakes

    Thanks for a good read, Nick!

    #3381546
    Anonymous
    Inactive

    Talk about a trip down the collective consciousness’s memory lane!   Thank you Nick for sharing that very interesting blog article.

    Perhaps, in some small way, the idea/concept to use a combo of thin walled, high quality Al 7075 alloy tubes, with foam and carbon fiber core, might be a small step in the evolution of the external frame in the areas of very high all around strength and very high durability.

    Normally, mixing Al and carbon fiber isn’t the best idea, as the carbon fiber tends to corrode Al, though anodization of the latter helps mitigate that.  But the foam will act as a protective layer in more than one way (mitigating both corrosion of the Al and compressive forces on the carbon fiber).

    #3381549
    Anonymous
    Inactive

    An update:

    Project has been going slower than anticipated.  Mostly because of prepping the 12 connecting points of the Al tubes that will be epoxy bonded.  Especially hard to prep is the inner part of the tubes/poles.

    While James says don’t worry too much about it, i’ve read several sources that say that anodized Al needs to be carefully and properly prepped in order to bond, because without doing so, you can lose up to 50% lap shear strength.  This is not so much because of the anodization itself, but from the sealing process that shrinks the pores after, which then lowers the surface tension of that treated layer.

    I don’t have a soda blaster nor high pressure washer i can convert (and either way, treating the inner tube with the former without stripping most of the inner tube’s anodization would be a real pain), so i’ve been doing it by hand with sand paper.  Since these tubes are hard anodized, it’s a rather thick and persistent layer of oxide to get through.  (maybe wrapping a drill bit with sand paper would work?)

    Lately, i’ve been having chemistry help me out, which has speeded up the process.  I took some sodium carbonate (“washing soda”) and mixed a high concentration of same in some warm to hot distilled water, and wet sanded in combo with that.   It’s just strong enough to help strip the oxide layer, but not too quickly or uncontrollably.  Also a lot safer than using a lot of the stronger and more quicker acting stuff like sulfuric acid, phosphoric acid, sodium hydroxide, etc (though, apparently both hydrogen and sodium hydroxide are created from the reaction of the Al oxide with the sodium carbonate).

    Immediately after sanding in the solution, i quickly rinse in distilled water, then a quick dunk in a very weak acid solution (a little ascorbic acid) to keep it from immediately re-oxidizing.  Not sure how effective that is or isn’t though.

    I’m almost finished with the above.  Last night, i attempted to bend two of the poles.  I packed sand in the tubes and bent by hand around my knees.  Stuff is stronger than it looks (i’m using the .49 Easton poles), but i was able to put some gentle bend in both–hopefully enough to keep off my lower back and shoulder blade areas.

    Plan to bond everything tomorrow.  To be on the safe side–after the epoxy cures, i’m also wrapping fiber fix around each of the joints.

    Does anybody know if FiberFix has carbon fiber in it?  If it does, it’s not be something i want to use on the exposed Al parts since it will speed up corrosion of the Al.

Viewing 16 posts - 26 through 41 (of 41 total)
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