If one want an Incubator say a 0 degree with 4 oz of overstuff. Would there be any difference than ordering a -15 degree Incubator?
Pete
If one want an Incubator say a 0 degree with 4 oz of overstuff. Would there be any difference than ordering a -15 degree Incubator?
Pete
Insulation rating for down is based on the amount of loft as opposed to the density of the down. My take on overstuff is that it helps with lofting faster, replacing inevitable loss of down, and may marginally increase the temperature rating, but not by much. I'm not familiar with Incubators, but probably ~3" loft for a 0F quilt and 3.75" for a -15F quilt. Adding overstuff won't increase the loft which is limited by the size of the baffle material.
Caminante, son tus huellas el camino y nada más... - Antonio Machado
Originally Posted by Caminante
One way to think of it that works for some:
If it was as simple as stuffing in more down... then why does everyone make down products in distinct models? From jackets to quilts the design needs to be tailored in roughly 10* increments for good reason.
An extra ounce or two for those expecting to be out longer (humidity loss) or simply seeking longevity and peace of mind make sense.
A regular 0* incubator lists 16 ounces of fill. Adding four is 25% more and a waste.
There is not exact science on it, but there is a tipping point where too much down would reduce insulating value.
It also makes the premium down product you bought bulkier to pack.
If buying a premium fill power down... by over filling it you're basically negating the reason you bought the premium. (IE- cramming in too much 900 fill is like using the right amount of 700 fill to start).
From a reputable vendor with a good reputation (pretty much everyone here).
I would suggest never exceeding 10% of the listed fill if you want to overfill.
So this zero degree incubator... 16 ounces of listed fill means 1.6 ounces. Going for 2 ounces won't kill it, neither will 1 ounce.
When I make my own stuff I tend to 'give it an extra pinch' just in case, so I get the impulse.
But after dozens or hundreds of building the same quilts I'd say the vendor has an excellent idea exactly how much fill is needed down to the gram.
In theory, overstuff shouldn't work, but it does. You're filling the limited baffled space with additional "hard" material whereas its the airspace that provides the insulation. But what you're doing by adding a little more down is making the quilt more efficient in terms of its technical specs. I would look at it that way rather than trying to hit a particular temp target with the extra overstuff. In other words, use extra overstuff to ensure your zero degree quilt will keep you warm at zero.
I believe the temp rating associated with an extra ounce of down is more anecdotal than anything. If the suggestion is that each ounce adds 5 degrees of warmth, that might very well be true in practice, or it might not. Even technical temp ratings based on loft have different practical truths to different people. Some need a 10 degree cushion (a 20 degree quilt to be comfy at 30), and some don't. Some will say they can go below a quilts rating.
What the extra down will give you is more structure that lofts more quickly and is less affected by breezes having a physical impact on the quilt (not necessary less affected by convection). This allows the quilt to feel warmer to you more quickly, which also has a physiological affect on your body in terms of relaxing your body's cold response. So, overstuff works, but to what degree it works for you and to what temp it will help keep you warm overnite is really tough to put a target on.
"I wonder if anyone else has an ear so tuned and sharpened as I have, to detect the music, not of the spheres, but of earth, subtleties of major and minor chord that the wind strikes upon the tree branches. Have you ever heard the earth breathe... ?"
- Kate Chopin
Also- another 'around the fire' example I use if it helps....
Picture a sheet of paper (8.5x11) an ounce of down would create a stack of paper equal to fill power divided by 100.
900 fill would make a 9" high stack
750 fill would make a 7.5" stack
A math whiz may note it would technically be a bit higher even- but a carpenter would tell you close enough in real life.
Unless you MYOG... I think most folks have a difficult time picturing how much an ounce of down really is.
A standard file storage box is 1800 cubic inches.
It would take 2 ounces of 900 fill down to fill it.
2.12 ounces of 850 fill.
So shoving 4 ounces of 850 fill is nearly two file storage boxes of down into a quilt that already has 7.5 file storage boxes filled with down.
https://www.staples.com/Staples-Basi...akamai-feo=off
Overstuff helps keep the temp rating, makes it loft faster and prevents down migration.
I have an old cottage quilt that was under stuffed by the normal standard. Yup its super light and packs down to nothing. But even new it took awhile to fully loft up. Now, after 75 nights on the trail it does not loft fully anymore and lost 7 or 8 degrees of warmth. A little overstuff ismt a bad thing, but all the quilts iv recently seen are already stuffed more then my old loved quilt.
Overstuff isnt needed is most cases unless you plan on abusing the quilt in some manner (excess use, wet, ect)
Last edited by chapinb; 09-13-2018 at 12:14.
Good stuff above. A little helps prevent shifting, which definitely helps the temp rating. Beyond 1-2oz of a properly stuffed quilt (which hammockgear quilts are), is, as said above, a waste.
Agree with most, if not all of what you're saying here.
The 5* per ounce thing was something that stuck me as a uniquely hammock forums adage. I'm a pretty big nerd and had not heard anyone attempt to make that claim.
If anything the hammock cottage vendors tend to be much more cautious than other cottage folks.
Backpacking Light used to be the hot place a decade ago, with folks like Tim from Enlightened Equipment and Paul from Arrowhead (among others) tinkering over there as MYOG folks prior to going commercial.
The goal used to be to find the absolute bottom, or perfectly filled quilt. This was an engineering minded xtreme ultralight crowd.
I do recall some debates about over filling a shell slightly to save some baffle weight (increase density at lower loft vs perfect density at maximum loft). Some folks did share that you could compress (overfill/increase density) with out much effect, but nobody ever tried to claim an increase in warmth... only that overfill didn't negatively affect down as much as we speculated.
Ultimately the minor increase in baffle weight in 7d shells is so minor it's not worth going down that road.
Two things though worth noting:
NOBODY has good data on underquilts. It isn't really a commercial/military application that has been tested or researched in the same depth that sleeping bags or clothing has been.
It does seem that most hammock vendors use roughly 1/4-1/2" more loft than a generally accepted loft chart for top insulation. Despite the lack of data in the lab.. I'm inclined to the trust field results and happy customers that these vendors have cultivated and trust their collective wisdom regarding properly filled products.
Hammock vendors (and their customers) are generally more conservative than backpack/UL minded cottage vendors. So for the most part I would consider any established hammock vendor here to deliver a conservatively rated product for the average user 'out of the box.' So while they do cater to their customer base in offering overfill; for the most part having that option is unique to cottage hammock vendors among down product vendors I am aware of.
Pure speculation on my part but:
Based upon my limited sales and contact with the hammock community at large, there is a high concentration of people in the south east states.
You could easily lose 5* worth of down loft due to ambient humidity in this area of the country in as little as a weekend trip.
I have taken perfectly filled and excellently tested stuff from the midwest here to the AT on multiple occasions and watched it wilt in the conditions in short time.
Western based outdoors folks in the drier conditions out west are often shocked by how much humidity creep affects down.
There is also a large chunk of the hammock community all along the east coast where humidity is not quite as vicious... but still very serious.
I would suspect that the large part of the '1 ounce equals 5*' topic might originate from that general user base.
As Dakotacross is pointing out... right out of the dryer your quilt probably rocks. But after one night in the woods it probably is under performing if filled 'just right' due to humidity.
So adding that ounce would buy you back 5* you've already lost... not five new degrees. You're overfilling to maintain, not increase.
A western hiker would tell you you're throwing your money away. A SUL designer would scoff at using more than is needed.
At the end of the day though... if those are the conditions you deal with then you need to deal with them. So practical knowledge may have morphed into conventional wisdom.
Rather than accept a 5* hit due to conditions... an extra ounce of fill may be the prevention you need to do the job if you hang in heavy humidity.
Bottom line- It doesn't hurt regardless- but don't overdo it.
Just Bill,
I'm glad that you have pointed out about the humidity hit. This has also been my observation. Although, I don't know how much loss of loft was caused by condensation inside the shell, or just humidity, or both. I personally have not had much problem with it during my hammock days. Last time I had that sort of trouble was as a ground dweller after 5 days in the Wind River Mountains, WY. The dry west! But despite NO external moisture contacting my bag, when I got back to humid MS, I measured and my 7" loft bag was now 5.5. And that was back when high quality stuff was well under 750 FP. But, I have certainly observed it happen to some of my hammock buds. Significant loft loss in 5 nights or less, with no rain reaching the quilts. Although, probaly the reason I saw zero issues on one trip where my buddy did- in the humid Olympics- is that I was all synthetic. An OCF pad in the HHSS(which did get the foot soaked first night due to condensation- and the foot end of a Polarguard bag also soaked. No matter, no loft loss that I could tell and plenty warm even before drying, which occurred quickly the next day. A full length AHE Ridge Creek 25F rated UQ(very conservatively rated IMO) weighs 20 oz. The 850FP WB down version rated 20F weighs 17.25 oz before adding 1 or 2 oz over stuff to improve performance in humidity and other areas. Oh well, the subject is not down vs synthetic pros and cons in humidity, so I might be hijacking. Still, if I felt I needed extra oz or 2 of down added to deal with humidity or condensation, on any type of regular basis, it would be something to consider.
Do you guys think the treated down is any better in the humidity or with condensation? If so, would that reduce the nee for any over stuff, in your opinions?
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