I recently found a "used" but mint condition military surplus four-part sleep system. It comes with the green "patrol" bag, the black "intermediate" bag, and the woodland camo Gore-Tex bivvy bag, with a black stuff sack for the lot. I've seen them for anywhere up to $200, so I was pretty happy to get it for $75 delivered.

I've read that if you store synthetic sleeping bags compressed for long periods that the insulation will lose its value. First, is this true? Second, what constitutes "long periods"? I bought this bag primarily to keep in my car during winter months.

It does compress to the point of damage after a few days. I use a bag twice as bîg, It shouldn't compress it too much.

Yes, if you store a sleeping bag compressed, the fibres will lose their loft (ability to expand back to their original shape and create those insulating air pockets). How long is long, well that is a hard question to answer... Depends on the materials, if it continuously compressed or not, how tight it was compressed, etc.

Due to this effect I do not use sleeping bags in any stored kits. It's far to waste full to keep my expensive sleeping bag compressed all the time. For longer periods of storage I would suggest wool or fleece blankets.

Full compression of a bag is not a good practice, which is why many high end bags come with a loose storage sack, as well as a stuff sack, employed when the bag is actually out on a backpack. However, I must say that I stuffed down bags for quite a few years into a fairly compressed storage mode, and never noticed a big difference.

It is always good practice to unstuff the bag well before you will use it, give it a shake or two, and let it expand to its fullest before you jump in.

I use synthetic bags, and generally store them in not very large stuff bags (though not fully compressed). Like hikermor, I have not noticed any significant loss of loft. One does need to open them up a bit before bedtime to let them fluff up, before crawling in.

While it is no doubt better to store them loosely, I think the alleged loss of loft from storing sleeping bags compressed is rather exaggerated, at least with regards to modern synthetic materials.

Hate to say it depends, but it does. Some synthetics and lots of down bags do not reexpand well after long storage compressed. Like hikermor, I have seen some good down bags that come out OK in a few hours. The old GI vacuum packed down bags (for seat pack survival kits) were pretty much worthless when opened (don't ask me how I know, just say I was glad to have an excellent parka that night). I have also had problems with lots of synthetic bags that would not expand well after months to years of compression. The newer Wiggys bags (like yours should be Chaosmagnet) have stayed vacuum packed for several years and came back to 90% within a few hours of opening. Check out the Wiggy's website wiggys.com for more information. (The usual disclamer here, just a very satisfied customer, several times). This is one reason they are the only bags I will use in a stored kit. If practical, I still do not compress the stuffsack if I can help it. In cold climates (not here >-() I carry one in my car in the sack supplied, but I do not compress it.

Respectfully,

Jerry

I agree on the exaggeration with the supposed compression effects of modern synthetic sleeping bags. I have one bag in particular that is only used in the cooler fall months and after being stored moderately stuffed all year,it decompresses quite well.

On the other hand, I have old synthetic winter bag, about 23 years old that is rated to -30C. Nowadays, that bag rarely gets used and does not decompress very well on its own. However 15-20 minutes in a cool clothes dryer, springs it back to its normal loftiness.

I would buy a Wiggy's bag if I could afford it. What I needed was something that would work in a wide range of temperatures and be small enough for my already overstuffed trunk, and $75 was about the maximum I could afford for that.

My camping is with my small children, so it's car camping and not when very cold. The sleeping bags we use for that are accordingly light. The new sleeping bag is intended to put the finishing touches on my "stuck in a snowbank for three days" kit, which is about the worst survivable thing I think is worth planning for when I'm road-tripping. It's meant as a major improvement over the Heatsheets Emergency Bivvy.

Geezer binge alert!

Back in the mid 50s, when I was discovering the outdoors, one of the best high end innovators was Gerry's (Colorado). They mentioned among other things in their catalog that they packed down items for the military, particularly SAC flight crews. I believe they depicted a vacuum packed sleeping bag, put up in the same container that usually contained canned ham.

Is this anything like the item you used, JF?

Synthetics lose loft after the first compressions. After that, they stay pretty stable at the slightly less efficient thickness.

What really kills synthetic bags is drying on hot. They can shrink several inches in length and loft.

Yeah, I know the Wiggy's bags can be vacuum packed but I haven't done it. But I have left them stuffed tightly rolled in stuff sacks for long periods of time without loss of loft. Disclaimer: I'm not affiliated with Wiggy's but I do have five of their bags!

An outward bound school I worked at had probably a thousand sleeping bags, mostly slumberjack and including a few hundred Wiggy's. They were all 20 degree synthetics. There seemed to be no difference in loft or warmth between brands and after several months of use they all were colder by a noticeable amount. In the CA Sierra Nevada, summer temps were sometimes down to freezing and the more used bags were not warm enough. Even sleeping in long underwear and fleece, the students with the older bags were cold.

I'd say store then in loose cotton bags - a big pillow case is good. and not in the basement or attic either.

When that happens you just throw the bag in the washing machine. That brings the loft back.

Believe me, these were well washed bags. Synthetic fill just wears out quickly.

I'm not buying it. My oldest one is over 10 years old and hasn't lost a bit of loft. Send it back then- two months or twenty years old Wiggy's will replace or repair it.

I don't know what they did with them. I didn't see them buy more in later years. They bought more of the slumberjack/kelty type bags.

Chaosmagnet,

Your Military bag is probably a Wiggy's. The tags should say if they are still in place. They are the prime and original manufacturer of the set you bought. The older style (which I think is what you have) are often available surplus or from former GI's for really good prices. Wash it as shown on the Wiggy's site, stuff it up, and be ready for serious cold. Not the lightest or most compact, but a serious cold weather bag at a super price. Just right for your need. I have and will trusted them for a while as my survival sleep system (in the car, in the airplane, in the canoe, sometimes even backpacking).

I agree, some of my worst nights were stuck in a snowbank type nights (usually on the plains of Wyoming or Montana, the wind gets nasty sometimes).

Respectfully,

Jerry

Consider the impact of a few consecutive weeks using your bags in the outdoors. I've been out 17 days and my sub 1 kg bag weighed more than 4 lbs. Body condensation. It has a cumulative effect on loft and sleeping temperature. You can sorta feel it later on a trip but generally after a couple weeks you're such a bad ass hiker it doesn't bother you so much.

I noticed my 11 year old sleeping bag which has been stored compressed the first 2-3 years, has lost considerable more of it's insulation than my 19 year old sleeping bag which has been stored loosely all it's life...

It's made by Tennier Military Products, a competitor of Wiggy's. There's an interesting short article on the military sleeping bag market at http://wiggys.com/legacy/jan08.cfm.

chaosmagnet,

Thanks for the information. I am glad you corrected my misconception.

Thanks,

Jerry

Store fluffy things loose.

A good, general rule