can you describe what dyneema fabric is like? i'm not sure if i may have come across it in any of my bags.
Ok, to be honest at first blush this is the first TB bag I don't really like the look of. The square flat flap and square pocket on the cylindrical bag just doesn't do it for me. I like the pocket in the flap and all, but the whole thing kinda bothers me.
I am sure it is functional and works with the drawstring, but a larger flap or different shape would make it more cohesive.
I do respect the fact that all the designs are always fresh and new.
original Wikipedia Entry for Dyneema given on the Tom Bihn web pages about a year and a half ago. It's more succinct for lay readers. For example, it begins:
and the second paragraph on its chemistry and properties starts:Quote:
Dyneemaź is a synthetic fiber based on UHMWPE, 15 times stronger than steel and up to 40% stronger than Kevlar. It is usually used in bulletproof vests, bow strings, climbing equipment and high performance sails in yachting. Dyneemaź was invented by DSM in 1979.
In contrast, the much longer current entry in Darcy's links starts:Quote:
Dyneema fibers derive their strength from the extreme length of each individual molecule. The fibre can attain a parallel orientation greater than 95% and a level of crystallinity of up to 85%. In contrast, Kevlar derives its strength from strong bonding between relatively short molecules.
and goes on to say:Quote:
Ultra high molecular weight polyethylene (UHMWPE), also known as high modulus polyethylene (HMPE) or high performance polyethylene (HPPE), is a thermoplastic. It has extremely long chains, with molecular weight numbering in the millions, usually between 2 and 6 million. The longer chain serves to transfer load more effectively to the polymer backbone by strengthening intermolecular interactions. This results in a
very tough material, with the highest impact strength of any thermoplastic presently made.
You can also read more about Dyneema in the packing cube thread, and my original post linking the old Wikipedia description:Quote:
UHMWPE is a type of polyolefin and, despite relatively weak Van der Waals bonds between its molecules, derives ample strength from the length of each individual molecule. It is made up of extremely long chains of polyethylene, which all align in the same direction. Each chain is bonded to the others with so many Van der Waals bonds that the whole can support great tensile loads.
When formed to fibers, the polymer chains can attain a parallel orientation greater than 95% and a level of crystallinity of up to 85%. In contrast, Kevlar derives its strength from strong bonding between relatively short molecules.
I can't remember removing the Dyneema Wikipedia Entry link from our site, but maybe I did at some point. :)
Someday soon we'll have our own materials glossary on the TOM BIHN site where we'll provide succinct definitions of the materials we use and links to more detailed definitions.
I just fetched back the link that Tom first pointed us to, because I found it clearer.
i bought mine recently! ^_^ i really like it for a number of reasons. the straps fit my shoulders great (a big plus because i have never had a backpack that fit me) and i love the design.
thanks, guys! i have been recommending you to my customers as well as my friends when they start talking about laptop bags. =D
Any developments on a cafe bag in Dyneema, Darcy?
Does anyone know if there is clothing available made from Dyneema? I have seen via Web search some body armor and gloves that use Dyneema as a component, but I want a wind breaker. I wonder if there are any bespoke/custom tailors that use Dyneema?
What's up with the Ruck's Sac? According to its web page, it is now down to being available in one exterior color (Olive). I had inquired about it, and it was said to be unavailable in Sapphire exterior. (I was interested in Sapphire.) Does this mean that the Ruc's Sack is being phased out, and the colors are not be replenished, or will the other colors be available sometime down the road?
I was hoping to order 2 Ruck's Sacs after the first of the year -- this thought makes me very nervous! PLEASE don't discontinue this bag!!