Nunatak Alpinist/ Inner Liner ??

Jay… I had the same thoughts when recently ordering my Arc Specialist. The Nylon Taffeta, at the same weight as Pertex, seemed a better choice to me. Softer to the touch, tough, the same sort of material that is found inside many jackets. It would seem that Tom is indicating as much when he states, "nylon taffeta is built especially for the lining side of ultralight down gear".

I agree with John, primarily because the taffeta is more down-proof than the outer fabrics. My Back Country Blanket is all spinnaker and loses the occasional feather on both sides. My Skaha Plus sweater is lined with taffeta and there's never a feather on my shirt after wearing. Taffeta also has a softer hand, not as slick as the Pertex Quantum on the outside.

With my Arc Ghost I went with the black 1.0 taffeta material for the liner.

Hey Thanks for all the great feedback- Ordering next week!!

>The Nylon Taffeta, at the same weight as Pertex, seemed a better choice to me. Softer to the touch, tough, the same sort of material that is found inside many jackets.

>I agree with John, primarily because the taffeta is more down-proof than the outer fabrics

Yeah, I remeber asking Tom about this, more specifically why the taffeta wouldn't make a good OUTER as well. At the time he said there was no reason why not to use the taffeta on both sides. So a better question to me is "why use Quantum at all"? Maybe it's a DWR thing??

I own 3 Western Mountaineering Bags (Great Bags) But the feather tips do eventually find there way out of the bags.
So Nylon Taffeta on both sides would prevent the feathers from coming out? How is the DWR on the Nylon Taffeta?

Quantum is ripstop and the taffeta isn't. Rips are probably not such a big concern for bags as they are for jackets or pants but no need to explain why you want it to stop as soon as possible if there is one.

I didn't know this data about the taffeta being more down-proof, is this hard data from the manufacturer or just from observation? I have my two Arc bags and Skaha lined with taffeta and there's the occasional feather poking out but never paid attention if more or less than on the outer Quantum. What I observed is quite a good part of the feathers and even some down stuff that poke out do it at the seams (which is where it's most difficult to bring them back inside).

Inaki,
not sure how ofetn you sleep in the bag (i.e. – 100 nights a year or 10) but FWIW i have a custom Alpinist (not Arc) and ordered it from the lightest possible materials at the time (was quantum).
the way i see it comfort is such a non issue as I seldom sleep naked (usually wear AT LEAST long johns and LS shirt and hat) so the touch of the inner doesnt bother me at all – of course the outer is where the real decisions have to be made (Epic/Quantum/eVent) but i assume you are going with the most UL there (i believe tom has 0.9 quantum??)
As per down proofness – again depends on usage. IMO the 1.56 feathers that get out every time i go through a compression cycle are totally irrelevant since if you are like me you will buy a new sleeping bag in 5 years at the most – and by then it would have lost about 0.03% of its loft due to feathers going through the shell. This is a bit different than clothing where movement during a whole day might take out more down.
Of course if you are one of those people (who i envy) that are out there 100~150 nights a year then i might think this over.

On the other had – ripstopping might prove critical at one point…might be the difference between a small tear and successful field repair and a large tear…

YMMV
Mike

Thanks for all the great feedback!!!! One more question-where does one add over-fill? To the head & neck area, torso, foot pocket or to just all the bag in general..
I just want to make sure I get this stuff right before making a big $$$$$ investment. Thanks again for any feedback…

-Jay

I would consult with Tom himself since he probabaly knows a thing or two about it ;)
That being said i believe over fill should be spread all over the bag with the same differential as the other fill (e.g. – if there is differential loft btw chest and foot then the over fil should be spread the same)
A caveat to that could be if you plan to use it with specific clothing (say have less fill at torso cause you plan to use down jacket

Mike

Their quantum may be a ripstop pattern, but quantum pertex
comes as a taffeta too.