Storing synthetic insulation compressed
Jun 21, 2021 at 11:41 am #3719451Jacob PBPL Member
One of the things I’ve always heard about synthetic insulation is that storing it compressed long term doesn’t cause issues with retaining loft, unlike down which must be stored uncompressed. The recent articles testing other claims about synthetic insulation have got me wondering whether this claim re: compressed storage is true. Anybody have any good data?Jun 21, 2021 at 12:42 pm #3719468Jim MorrisonSpectator
@plinyLocale: Pacific Northwest
I have two Coleman medium-quality sleeping bags we use for car camping. They stayed compressed for 10 months at a time between uses. I never noticed any loss, but that is subjective and the difference may not have been noticeable. I definitely store my down bags in large mesh sacks on the top shelf of the closet when not in use. Of course, they are compressed, but not tightly, in the bottom of my pack between uses on the trail. Apparently, there is experimental data that shows loss of insulation value fo synthetics when stored compressed. try this link; Millard2-1992.pdf (lboro.ac.uk)Jun 22, 2021 at 7:35 am #3719545
Jim-Do you have a better link to this study? I have not succeeded in finding it.Jun 22, 2021 at 3:20 pm #3719596Paul SBPL Member
I have read over and over again that synthetic insulation (most kinds) loses its loft far faster than down.Jun 23, 2021 at 12:20 am #3719636Ivo VanmontfortBPL Member
@ivoJun 23, 2021 at 6:47 am #3719638
Thank you for the link. As it happens, my next By the Numbers article will deal with this subject and use the some of the same test methods described in the PDF. It is scheduled to be published the 1st week of July. Stay tuned.Jun 24, 2021 at 11:26 am #3719913
It’s been my experience that storing any high-loft article compressed has degraded the loft. the main differences I find in what hurts the loft of synthetic versus down is that heat is the worst enemy of loft with synthetics – not good for down either, but worse for synthetics – the worst case being a stuffed synthetic bag in a car trunk on a desert summer afternoon. For down the biggest problem is moisture – store any down article damp – or just in a damp basement -and it can be ruined, while the synthetic will survive being stored damp as long as it’s uncompressed.Jun 24, 2021 at 12:32 pm #3719934
Can you be more specific with any of your experiences? For example, how old was the item, was it short staple insulation or continuous filament or what brand of insulation. Those may be the most important characteristics we should be concerned about.Jun 30, 2021 at 11:17 am #3720670
Most of my experience, and that of my friends, is with various generations of Polarguard, from the original thru 3D, which were all long staple. Age of the piece has little to do with it; usage does. I have a vest I made using the original Polarguard, about 1978 or so, which has had very little use, and has never been compressed for any length of time, and it has all the loft it ever had. Back when I worked in the outdoor retail world, we had rental bags of both down and synthetic, and the synthetic were Hollofil 2, (short staple) – they lasted a summer and by the end they were less than half their original loft. They had to be laundered each time they were rented, per state regulations as I recall, and so they had hard usage and frequent launderings. I have always been very careful with any high loft articles, whether down or synthetic, to store them loose, and when I wash them, they go on the drier only on air fluff, no heat. Friends of mine, not quite so careful, have seen significant loss of loft with their synthetic bags, of both Polarguard (the old stuff) and Thinsulate Lite Loft – which I don’t think is still made, but was short staple I think.
Climashield is, as far as I know, essentially the successor to Polarguard, taking up where they left off with long staple synthetics and continuing to refine the process. It certainly seems like almost the same stuff when you handle the raw batting; I have made gear using both. I have never made any gear using any of the short staple insulations, as I have never seen any data to suggest they are superior in terms of warmth per weight in a finished article, and all experience I have ever heard is that they don’t maintain their loft as long. One of my old friends used to work for Moonstone mountaineering back in the day when they wer making the pemier synthetic bags, and the owner had several bags made up using all the available synthetic insulations, and proceeded to torture test all the bags, leading to the conclusion that the polarguard was the best. you could make a bag with Thinsualte Lite Loft that was slightly superior on the showroom floor, but it lost that advantage almost immediately once it was put to use, and was soon way behind the Polarguard bag. Now of course all these insulations have changed in the years since, but the central factor that I don’t think has changed is that long staple synthetics are still the best, at least for sleeping bags.
I don’t have a lot of synthetic stuff anymore, but I do have a pullover and pants made with Polarguard 3D that are about 15 years old, and they have not lost significant loft or warmth, being kept loose when not on a trip. I also have an overquilt I made using Climashield, that is only a few years old, that is still in perfect shape.Jul 1, 2021 at 11:05 am #3720733J RBPL Member
I thought the notion that compressing down degrades the loft has been largely debunked.Jul 1, 2021 at 11:23 am #3720735
I think it is alive and well and you can look no further than Ryan’s insulation master class video. If you have some sources that suggest otherwise, can you post that information? There are two aspects of compression that are of interest: Simply the compression force that results in loss of insulation resilience and the impact on compression cycles on insulation resilience. My 1st article on insulation degradation I think will post at the end of the week.Jul 1, 2021 at 11:36 am #3720738
Thanks for taking the time to respond. I think an important issue that you raised is that these insulations have changed over time. I am aware of some changes in Primaloft and have written about these and discuss that a bit in the insulation degradation article that will be posted shortly.
As for changes Climashield as implemented, I simply cannot speak to that issue. I know that fiber diameters in Apex and Polarguard 3D are nearly identical, but I don’t know how other parameters of their insulation features may have changed and how those features may impact degradation.Jul 1, 2021 at 3:50 pm #3720769J RBPL Member
Stephen, I don’t have sources, just that I have read plenty, including on this forum, of people who have left high-quality down bags and jackets compressed for years and they spring back once unfurled, albeit the item needs more time to re-loft after that much compression. Lower-quality feathers have been reported to not spring back well but high-quality down has been reported to be fine. But I’m no engineer, I haven’t conducted these tests myself, I can’t cite specific sources, and as a matter of practice I store all my down unlofted “just in case.”Jul 1, 2021 at 4:29 pm #3720775bradmacmtBPL Member
I guess Western Mountaineering, et al supply storage sacks for no reason…Jul 11, 2021 at 10:02 am #3721652
One other thing I remembered is that my friends who had long term experience with synthetics and loft degradation felt like the loft reduction did not track with the thermal performance – one guy’s comment was that he now had a thinsulate bag instead of lofty one, but it was almost as warm. so that suggests that maybe you don’t lose insulation capacity as fast as you lose loft.Jul 11, 2021 at 10:36 am #3721653
I have no doubt from my testing experience that is correct. I will also tell you, having put a lot of effort into it, it is simply difficult to measure the loft of batt insulation. The insulation thickness of a bare batt varies, as described in the first article in this series, so optical measurement, using a laser is not a very good solution. Measurement techniques from standards apply pressure to the sample being tested. Nearly any pressure applied to 6 osy Primaloft will cause distortion. So, it is a problem. Of course, when sewed into a garment, you are never likely to obtain full loft. When I start the next round of compression tests, I will measure loft as best as I can, but the guarded hot plate measurement is the test I will rely on and really, the one that matters most.
Thanks for reading.Jul 11, 2021 at 6:56 pm #3721681Bryan BihlmaierBPL Member
@bryanbLocale: Wasatch Mountains
From what I’ve read on BPL (Synthetic insulated jackets state of market report by Max Neale), it’s not just leaving synthetics compressed, but over-compressing them, that degrades the loft. Hopefully Stephen’s next article will address both aspects of compression.Sep 12, 2021 at 2:52 pm #3727235Russell LawsonBPL Member
@lawsonLocale: Olympic Mts.
I made a 5oz climashield quilt eight years ago, used it for about two years straight everyday, as well as took it out a bit the other years, always stored in a bag but not generally compressed, was perfectly fine until about year four when I really packed it hard into a tiny backpack multiple times on a trip. That cut off about 10-15 degrees to it’s R value I’d estimate.
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