MYOG: Backpack fabrics, features, and dimensions
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 Ryan Jordan (ryan) - BPL Staff - MLife Locale: Greater Yellowstone MYOG: Backpack fabrics, features, and dimensions on 07/30/2014 00:29:06 MDT Companion forum thread to:MYOG: Backpack fabrics, features, and dimensions
 Jon Holthaus (t25hatch) - M Great article on 07/30/2014 08:33:47 MDT This is a just a fantastic read. Thank you for your generosity of showcasing your experiences and successes with pack building. I have emulated some of your designs with a few minor changes, and I have to say I'm very satisfied with the results. The material comparision is far more in depth than your other writing on this topic. A number of the topics in this article have been discussed on different forums and blogs, however this is an all inclusive article that explains pack design and features very well.Thank you for sharing your knowledge.
 jerry adams (retiredjerry) - MLife Locale: Oregon and Washington Re: MYOG: Backpack fabrics, features, and dimensions on 07/30/2014 09:06:56 MDT More excellent information about packs, thanksBut, you said circle provides 50% more volume than square with same circumference.Presume that volume is proportional to area, since you're talking circles and squares.Area of circle is circumference ^ 2 / (4 * pi)Area of square is circumference ^ 2 / 16Ratio is 4 / pi = 1.27Circle provides 27% more area than square with same circumferenceand in reality, all pack cross sections are some sort of flattened, circular shape, so differences aren't that importantyet your point is valid - it's hard to measure/compare volumes - I should just let your error slip by un-noticed : )
 David Chenault (DaveC) - BPL Staff - F Locale: Crown of the Continent Re: Re: MYOG: Backpack fabrics, features, and dimensions on 07/30/2014 09:48:29 MDT I will fully own that geometry is not my strength.
 Roman Vazhnov (joarr) - MLife Locale: Russia re on 07/30/2014 14:09:25 MDT Dave, thank you for the article! Have you seen Si\Si Cordura (210d, 420d) available anywhere?
 Roman Vazhnov (joarr) - MLife Locale: Russia pictures are missing on 07/31/2014 02:26:38 MDT "Examples above are the Paradox Unaweep at left, a two dimensional pocket, and the Gossamer Gear Gorilla at right, a three dimensional pocket."
 Sam Haraldson (sharalds) - MLife Locale: Gallatin Range MYOG: Backpack fabrics, features, and dimensions on 07/31/2014 08:31:52 MDT Regarding pack volume, the American Society for Testing and Materials (ASTM) test F2153 can be performed at home by filling your ruck with a known volume of small, plastic spheres (i.e. ping pong balls). Pre-determine this "known volume" of ping pong balls by first filling a rectangular container with water, added one liter at a time marking the sides of the container in 1, 5, or 10 liter marks. Remove the water and then pour the spheres from your ruck into the rectangular container to see how many liters of spheres the ruck contained. Backpacking Light built a system like this for accurately measuring the volumes of the Absaroka Backpacks sold here some years ago. You can see a photo of a similar method to this in one of the State of the Market Reports published here: http://www.backpackinglight.com/cgi-bin/backpackinglight/lw_internal_frame_packs_part_1a.html
 David Chenault (DaveC) - BPL Staff - F Locale: Crown of the Continent Re: pictures are missing on 07/31/2014 09:09:28 MDT Oops, looks like a few things got left in when I cut this down a bit during final edit. Will see about fixing.
 David Chenault (DaveC) - BPL Staff - F Locale: Crown of the Continent Re: re on 07/31/2014 09:48:36 MDT I have not. It's seemed to me for a few years now that the obvious next step for heavier use fabrics is a 400ish denier plain or basket weave with some manner of impregnation on both sides. Some of the Arcteryx fabrics come close. Haven't seen anything like that for sale at retail.
 Roman Vazhnov (joarr) - MLife Locale: Russia materials on 07/31/2014 12:14:33 MDT What about woven dyneema fabric? Some kind of it is available on aliexpress.com for example. Does anybody tried to make a MYOG pack out of it?
 Bill Townsend (Olmanwilly) - MLife Locale: Midwest Good work on 08/06/2014 14:06:55 MDT Tossing the flipside of your fabric weight argument out there: As you point out, at a yard or so of fabric- weight isn't the main thing to consider. But cost really shouldn't be either. An extra \$10-\$15 (assuming a final design) isn't a deal breaker, barely a factor really. With that in mind- Would you give the bump to a cuben hybrid in a 50d/cuben vs. VX 21?Or a 150d CFH vs VX 42?You make an excellent point regarding reinforcement, stitching etc. in favor of the heavier products. Ease of construction and clean lines are a big help as well. The lightest of light isn't worth it, but when speaking of the middle of the road between safe established trails and excessive abuse in a canyon- the fabrics above seem to be a good balance of weight/durability. But what about your compelling arguments? Ease of construction, reinforcement, etc. Can you sew a CFH just like regular fabric?Is the taping, crazy reinforcement and arduous technique solved with the addition of the face fabric?I find the CFH compelling (Zpacks seems to as well)- I would appreciate more info/feedback/comparison from anyone on those aspects. It seems like this hybrid solves all the construction and field issues but I find little info from MYOG folks who've used it. I greatly appreciate the feedback on the Dimension fabrics- that is hard to come by for sure! Bit off topic- anyone have a source for that super stretchy mesh mentioned. Heavy I know- but handy to have a yard for little stuff here and there. The circumference thing threw me off- it read more like a tubular body rather than the true four sided construction. Sorted it out as I caught up on the series, but from a construction standpoint you're building a rectangle. From a measurement standpoint- I understand using the circumference.
 David Chenault (DaveC) - BPL Staff - F Locale: Crown of the Continent Re: Good work on 08/07/2014 10:56:09 MDT Bill, I haven't used the 150D hybrid cuben long enough to really comment on durability. Given how easily I was able to put holes in that fabric (toting snowshoes wore through the face fabric in a day), I can't see any personal use I'd have for the 50D version. Honestly, comparing the 150D hybrid with X33 at effectively identical weights, it's hard to see what you're getting with the former, aside from more money spent. Theoretically the hybrid has a higher tear strength, but lower abrasion resistance, which in my experience is far more relevant.The stitch hole elongation issue is an interesting one which merits further research. It seems plain that needle holes in cuben hybrid do not self heal at all, Dimension Polyant fabric do this as well, but to a much lesser extent (one assumes due to greater mass in the "normal" fabric portion). I've not experienced visible stitch hole growth in VX07, VX21, or VX42, this in normally sewn (ie not felled) seams joining side panels to back panels (which seem to experience the greatest torque). Contrast with the HMG packs. Every 3400 or 4400 pack I've personally seen which has seen significant use (eg >200 miles with 30 or more pounds) has easily visible stitch hole growth. Does this lead to longterm issues? I can't say, but it makes me hesitant to invest in hybrid cuben.