Nov 14, 2011 at 7:37 pm #1281975
I'm working on making a pack, and, frustratingly, I feel compelled to continuously amend the design during the construction process. One of my aims was to achieve better ventilation than some of the other packs I've owned. I hope to improve my comfort during hot summertime hikes.
I don't really like the trampoline-back solution because it requires a rigid frame. Also, I'd like to use it for trail running and a pack that sits pretty snugly against the back bounces less. My target weight for the pack is 15-18oz.
One of my initial ideas was to use a thin layer of very breathable and resilient "reticulated" foam on the back and in the straps (image below). It's made of urethane and often used for filtration. I acquired some that's blue and has ten cells per linear inch. It's very bouncy and a breeze goes right through it.
I also considered 3D spacer mesh, but the stuff I've used in the past (and the material I've seen in packs and shoes) is pretty thin (1/8") and too compressible. It just gets squashed flat in use. It doesn't actually create any air space.
I found, though, that giant spacer mesh, with very open, netting-like face fabrics, in thicknesses from 1/2" to 1" are used for seat padding in some European recumbent bicycles and in under-mattress pads on boats. So, I bought some for experimenting.
It is very airy, and I can see through it. It is about 1/2" thick. In the second photo the thickness is compared to some standard 3D spacer mesh from DIY Gear Supply. It is very firm and bouncy. The specs say an area of one square yard will support 375 lbs. When I sit on it on a linoleum floor my butt doesn't flatten it.
It isn't light (about 20 oz/yard), but, for my project, I probably would only need about two square feet of it (or about 4 oz), which is probably only a net increase of about two ounces over the standard spacer mesh and foam it would replace. It is allegedly much more resistant to compression-set than foams (this is one of the benefits in applications like recumbent bike seats). The surface is slightly abrasive, so I'll probably try putting a light knit fabric over it wherever it might be in contact with skin.
I thought some of the MYOG crowd might be interested to know that this stuff exists. I'll post photos of it in use once my pack project is finished.Nov 14, 2011 at 7:47 pm #1801838
Paul McLaughlinBPL Member
I've used reticulated fiber as back padding on an internal frame pack, covered in leno mesh. In use I don't find that I sweat any less than with a solid fabric pack body, so I don't use it any more on my packs.Nov 14, 2011 at 7:51 pm #1801839
Daryl and DarylBPL Member
@lyrad1Locale: Pacific Northwest, USA, Earth
Thanks for the info.
I'm thinking this might be good for waist belts and shouder straps too.Nov 14, 2011 at 7:54 pm #1801843
@namaniacLocale: SoCal-High Desert
Can i ask where you got the Giant Mesh from??
Im ready to buy some myself and i think i want something thicker for my hipbelt than the 1/8" most places sell….Nov 14, 2011 at 8:18 pm #1801854
The material is called "Drymesh" and it is made by a German company and distributed by a UK company that has an office in Connecticut (www.drymesh.net). It is only sold in 72" x 78" pieces (6 x 6.5 feet), for about $70 (roughly $17/sq yard).
Because they only sell big pieces, I have far more than I can use, and I'd be willing to send bits of it to anyone who would like to experiment (for the price I paid per unit area plus shipping).Nov 14, 2011 at 8:37 pm #1801865
@davecLocale: The West Slope
Looks like the stuff Golite uses on the backpanel of the newest Jam and Pinnacle. Very effective. Only issue I have is pine needles get inside it like mad.Nov 14, 2011 at 8:44 pm #1801869
Jeffs ElevenBPL Member
yeh looks like the stuff camelbak uses on some of their back panelsNov 14, 2011 at 9:21 pm #1801877
@namaniacLocale: SoCal-High Desert
PM sentNov 15, 2011 at 12:01 am #1801910
@stingray4540Locale: South Bay
Very interesting approach! I'm also looking into improving ventilation of a SUL pack, but so far I've been looking towards the trampoline solution. Please post your results when you finish, as I'd be very interested to see how it turns out.
P.S. I'd also be interested to hear why you chose to move from the reticulated foam to the 3D mesh. The RF certainly looks more airy. Is the 3D lighter? Some other reason you chose to change?Nov 15, 2011 at 5:49 am #1801942
Jerry AdamsBPL Member
@retiredjerryLocale: Oregon and Washington
Maybe it would be good for the shoulders of a rain jacket. And the hood.
The fabric always compresses at shoulders and hood, and gets sweaty even if the outside is waterproof.
Maybe this foam would provide enough airspace to make this better.Nov 15, 2011 at 9:50 am #1801996
"I'd also be interested to hear why you chose to move from the reticulated foam to the 3D mesh."
The foam is lighter and more compressible than the spacer mesh. I plan to use the foam in the straps and the firmer, heavier spacer mesh in the back panel.
The outside face of a pack strap is exposed to the air, so an improvement in ventilation can be achieved just by using padding material and fabrics that are airy or have an open weave. They don't need to be incompressible. They don't need to be able to maintain a space between you and the strap as long as they allow air to pass through the strap.
But air can't pass through the pack. The only path for movement of air against your back is through a space between you and the pack, so an improvement in ventilation can only be achieved using something that can resist compression and maintain a space.Nov 18, 2011 at 10:58 am #1803137
I just picked up a yard of the IOTV mesh from ahh.biz.
I bought the foliage green and plan to use it for back panel cutouts. It's really thick, but when you press on it, it compresses or folds over. I'm not sure I'm going to use it for shoulder straps, but for the back panel, it looks primo. I'm still awaiting some other materials before I start constructing my pack. I'm not going to need the entire yard, so I'd be willing to share….a couple square inches for samples at $3 shipped or a 2 square feet for $20 shipped.Nov 18, 2011 at 7:46 pm #1803270
Sam FarringtonBPL Member
@scfhomeLocale: Chocorua NH, USA
By trampoline, I'm thinking you mean a suspended mesh back panel.
That does not require a rigid frame, like the ones on Osprey packs, for example. In fact, a frame with some (but not too much) flexibility works better, in my experience. I have one with a very flexible ABS frame, and am working on an even more flexible and lighter one using bowed quarter inch carbon rods. The trick is to have as much flexibility as possible without allowing the pack contents to poke or rub through against the back.
While the suspended mesh is good for ventilation; if correctly designed, it also elminates any pressure points against the back, which is of great importance to someone like moi who has suffered a fractured vertebrae.
But despite many efforts, I've not been able to come up with a suspended mesh design that is very light, meaning that my best target weight for a 5 oz., 3000 cubic inch Xpac fabric pack is around 2 lbs.
If you can come up with a light flexible mesh lattice that is soft enough to be comfortable, and allows plenty of ventilation, I think you will have found a significantly lighter alternative to suspended mesh for most BPers who don't need as much back protection, but want good ventilation.
Good luck with your efforts.Apr 29, 2012 at 10:37 pm #1872611
Colin, I know that it's been some time since you made this post. I was wondering if you or anyone on this forum has 1-2 square feet of the giant spacer mesh they would be willing to sell to me. Thanks!Apr 30, 2012 at 3:39 am #1872629
I've recently used the black mesh with clear strands in it (first post, last pic). From extremtextil, 6 mm thick if I remember correctly.
Used it on my backpack for shoulder straps and hipbelt. Works well, in my opinion a nice rigidity to it.
Note! I used a thin edge binding webbing for it, which meant the transparent strands could poke through it. I didn't like that part, fortunately I didn't notice it during winter camping, we'll see how it works out with a t-skirt – did cut off all visible ones. Else I'll have to redo the edge binding.
Quite heavy as noted, but the pieces aren't that big and I'm generally prepared to pay a bit extra when it comes to the weight transfer system.
Edit, clarification on pic.Apr 30, 2012 at 9:59 am #1872710
Tim, I have a little bit left of the giant spacer mesh for an upcoming project, and I gave the rest of it away. I don't have any more that I could send you.
I really like it, actually, and I plan to use it on another pack, but it is a profound pain in the a** to sew. Standard spacer mesh doesn't require any special sewing techniques, but this stuff is a challenge. It cannot be machine sewn, because the z-axis fibers that maintain the space between the face fabrics are pretty rigid, and smashing them down with a machine seam causes them to buckle and form a hard, abrasive bundle of crimped and tangled plastic wires. It can be sewn neatly and successfully by hand, but each face needs to be sewn separately, and this is very tedious. The face fabrics, in other words, cannot be brought together. You have to imagine that your piece of spacer mesh is a flexible but incompressible box, and deal with the two faces separately in your design. To bind the edges, you need a curved suture needle and wide bias tape that can reach around both sides to make a square cross-section edge. The bias tape has to be sewn separately, by hand, to both faces. You can't collapse the material and force it through the sewing machine to bind the edges.May 3, 2012 at 3:22 pm #1874098
Colin, thank you very much for the additional detail! This is very helpful. Have you found a way to simply hem the ends of a mesh piece, instead of joining two ends together?
Also, have you found any other suppliers of the giant spacer mesh, other than the German company you mentioned?May 3, 2012 at 3:57 pm #1874104
Tim, I haven't found a way to hem this material. The only way I have discovered to finish the edges is with wide bias tape wrapped around the edge and sewn separately to each face fabric.
I haven't found any new suppliers. I know only of a Danish recumbent bicycle company that sells 20mm thick material in small pieces, and the British company selling large pieces of a 10mm thick German product through a distributor in Connecticut.May 5, 2012 at 2:44 pm #1874701
Colin, any chance you may be able to send me the leads to the distributors that you've been able to find? I'd like to try to various options that are available. Thank you very much for your help!May 5, 2012 at 8:02 pm #1874783
Tim, I only actually made contact with two companies that will definitely sell the material. the Danish company is here:
The British company with an office in Connecticut is here:
You might also be able to obtain samples from these companies:
Good luck, and please let me know if you find that any of the last three will sell material in small quantities (and post what you make if you get some!).May 7, 2012 at 11:09 am #1875271
Awesome! Thank you very much!
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