Arc Alpinist custom options

[John Gelack]

I am intrested in ordering a Nunatak Arc Alpinist and I was wondering if someone can give me some advice on custom options. Should I order the quilt with the standard fill or should I ask for the overfill option, and if so, how much overfill should I specify that I want? I would also like to order the quilt in a black color to aid in sun drying, but the only fabric choices Nunatak currently offers in black is 1.1 ripstop nylon or Epic. I wish I could have gotten it in Quantum, but they only have it in orange now, I missed out on the dark green. Which fabric would be the better choice? I already have a Vapor bivy to protect the quilt from rain spray,dew,ect. So I am leaning towards the 1.1 ripstop for lighter weight and I would think better breathability. What is your opinion? I would like to use the quilt for 3/4 seasons in the Northeast. I really appreciate any advice you can give me. thanks John

[Richard Matthews]

Tom has my Arc Alpinist now to add 2 oz. of overstuff and to put buckels on both ends of the straps.

The straps get in the way unless you need them. I have only needed them a couple of times and I am going to store them in my pillowcase/stuff sack.

I agree with your comments on the fabric.

[Jason Shaffer]

Hi John
Check out the reader reviews and the articles here if you haven’t already. Lots of people agree on a little overfill only to prevent shifting of the down. 2oz spread somewhat evenly was my pref, others might like most of it in the footbox.

As for fabric, I”ve got a different take: fabric performance trumps color performance. Just to be clear, 1.1 oz/yd2 ripstop is heavier than .9 oz/yd2 Pertex Quantum. (Sorry – it kind of reads to me like you’re saying the other way around in your post. If not, my apologies!) Also, most if not all 1.1 ripstops are less breathable than .9 Pertex Quantum. Even Nunatak’s .85 ripstop is ~slightly~ less breathable than PQ. But .85 (in blue) could be a better choice than PQ if you’re willing to sacrafice some external moisture resistance, as well as an albeit miniscule amount of breathability, for the sun-drying factor.

If you’re unsure, you could ask Tom to break down the fabrics on a spectrum of breathable v. resistant to external moisture.

Epic is far less breathable still, but the concept is the same: any compromise in breathability causes more internal condensation, requiring more ‘sun-drying performance’ to begin with.

I swear by my Vapr, definitely useful for the ‘external’ moisture control w/out itself hampering breathability. But it doesn’t compensate for lack of breathability in the lower layers per se, tho it does add another temperature gradient which ~can~ move the dewpoint outward. But Epic shelled bags, for ex, kind of defeat the strengths of the Vapr bivy (over multiple nights anyway), esp if sleeping in damp clothes in cold weather when breathability of all layers is key. Anyway, in warmer temps and/or short trips these differences are hard to notice, but 30s and below for longer trips is another story in my experience, with any kit. Depends on your goals. Best of luck!

[David Reid]

I went with pretty much the standard setup with no overstuff in my Arc Ghost. So far I have taken it into the mid 20’s without problems so I’m pretty happy I didn’t get any overfill.

I have the .85 ripstop and have not had any rips. I do use a bivy sack if there is any moisture expected although I haven’t had any problems with light moisture soaking the bag.

Tom did add 3 inches to my medium bag for a nominal fee. I’m 6′ tall and thought I could get away with the medium size. When they say 5’10” they are not kidding.

The cool thing about any options that you pick is that Tom will modify the bag for a nominal charge if you find you don’t like something.

[George Gagesch]

I recently received my AA. I had ordered mine with Pertex Quantum (green)inside and out. Guess it was the last one because Tom called and said they didn’t have enough material to do both sides. Instead they put the 1.1 black fabric on the inside. It was something that I was considering anyhow for aid in drying. The only change I made was to overfill the top half of the bag 1 oz. I had problems in the past with down shifting and I am a bit of a cold sleeper. The difference is when the quilt is layed flat the upper tubes puff up to a roundish shape. The lower section has plenty of down, but not as visably puffy. Slept outside in the yard like a baby with temps in the low 30’s. Removing the straps would be nice for warm weather use. I would go with the .85 before getting something more water proof. If it can’t be dried easily it won’t be warm for long. They also had the .95 material, but Tom was not real confident about it. Tom had also mentioned that the Pertex manufacturer had gone bankrupt. Any word if they will be getting more PQ? If so it might be worth the wait. Good luck with your choice. It’s a really nice bag.

[John Gelack]

Its been a few weeks since I posted this question. Ive had a hard time trying to decide which options to get. Since this is a pretty expensive investment, I didnt want to make the wrong choices. Ive finally decided to order my bag with 2oz of overfill, and a third strap added at the shoulder. I really like the idea of adding buckles to both sides of the straps, this way I can leave the straps at home in warm weather. So I will also ask for this. I just wanted to thank everyone for their advice. John

[Mike Storesund]

I did not have any customization on my Alpinist. If I had to do it again, I would agree that having buckles om both sides would be an advantage. For now, when I do not need, I roll them up and use a little High Visability tape that could be used as marker in an emergency.
I have not needed added fill, but then I had to add clothing to compensate for below 20 degrees.

[Pedro Arvy]

The very first review of this bag by Dr RJ mentioned differential cut. Does anyone know what this is and whether it is a standard or a good idea to ask for?

[Vick Hines]

A sleeping bag with differential cut is one in which the outside shell is larger than the inside shell. Think of two concentric circles. The outer circle has a longer circumference than the inner. In a down bag, the baffles are cut into arcs to match the inner and outer shells.

The advantage of the differential cut is that elbows and knees don’t poke against the insulation. The insulation achieves full loft and full efficiency at all times. The disadvantage is that a differentially cut bag does not fill the space around the sleeper, and that extra air must be heated.

The second pattern is the so-called ‘space filler’ cut in which the inner and outer shells are the same size. The insulation poofs around the sleeper. It is ultimately less efficient, but more comfortable initially. The space filler cut will generally need a little more down and loft to achieve the same temperatures as the differential cut. The third cut is a compromise between the differential and the space filler.

Differential cut is used in high-performance bags where every fraction of an ounce matters and the user does not expect the same comfort as a space-filler cut.

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