Are you talking about something like the north face version?Originally Posted by Brooklyn
https://www.thenorthface.com/about-u...hermoball.html
Are you talking about something like the north face version?
https://www.thenorthface.com/about-u...hermoball.html
First, what difficulties do you mean, constructing with PLG? Just the quilting?
Quilting, cutting, material handling and limitations. I have two techniques I will not share that increase the labor to the level of down costs. But it tends to shed more than apex and end up on you, your shop, your machine, your clothes, etc. Bit like down at times when handling. Some of those are production issues that don't apply to MYOG, but commercial sewing contractors don't like to work with it. The rolls are much more difficult to deal with compared to Apex as well. For MYOG... hope you like pinning and own lots of pins. It takes me longer to make a good PLG quilt than a down one without specialized equipment.
Does the necessary stabilization quilting have to be stitched, or can it be looped as normal?
You can only loop quilt with continuous filament insulations (Apex) Technically you can't do it with Apex either. Again not to pick a fight since we all violate this rule, but Apex requires quilting 24" OC for stabilization. I don't disagree with using loop quilting for continuous filament insulation, but that is the reason you don't see it done in commercial gear, it's not supported by the supplier. Can't think of a cottage vendor who doesn't break that 24" rule though... so can't think of a reason to discourage you from loop quilting, especially with multiple layers.
Primaloft Gold (short staple) requires stabilization quilting 6" OC. I know some MYOG folks who have pushed that to 12" oc, and a few who just sewed them up like apex... but you tend not to hear much follow up from folks who've done that. I would think though you could push to 9-12" for personal use without any horrendous effects; but that depends how nice you are to your gear or how long you expect it to last. I would think you'd get a solid season (100 nights) out of it. The scrim layer is NOT sufficient to quilt to for stabilization. (it's like synthetic tissue paper) So don't get any bright ideas like I once did.
Since I don't use down for various reasons, how would you recommend constructing winter-temp insulation? I want to get sub-10F, as a reference. And by the way I'm used to bulk; I don't worry about it overmuch, just try to keep the ounces down.
This is tricky... I'm philosophically and technically opposed to synthetic at those temps. Down is much better on many levels.
The CLO formula was intended for HVAC design and never really works right as you approach zero degrees. Things get a bit screwy and the formula breaks down. My personal theory is that at that point you're back to the basic loft chart... and you'd need way more insulation than you would if you're talking pure CLO.
In theory, if you follow the basic Apex guide (2, 4, 6, 8= 50,40,30,20) that's oz to temp. Then you see that roughly 2 oz/sy adds 10 degrees. Or 1.64 CLO = 10*F or .164 CLO per degree F
So... to get to -10 (if you could) then you need 30 degrees past the 20* or 6 oz more Apex for a total of a 14oz/SY of Apex. Or three layers of 5 oz?
In theory that is 4 3/8" of apex if it held the roughly 5/8" thickness per 2oz batt (which it doesn't so far as I know because the APEX doesn't increase lineally in depth).
So a return question... how thick is a 5oz batt of Apex? Now multiply that by 3. Now check that height against this chart- http://www.zpacks.com/quilts/down_loft.shtml
So if it's not 3.5" thick, I don't think it will work, and check it against my chart and you will see that 800 FP down would weigh 7.4 oz/yd at -10.
In an average top quilt of 2.5 yards of material then... (2.5x7.5)= 18.75 ounces of down and baffles vs (3battsx 5oz per batt x 2.5)= 37.5 ounces of Apex fill.
That's assuming it would work... which at some point somebody here will pipe up that they have indeed built one and it worked well enough... though I suspect it's mainly because at some point you simply had enough LOFT, not enough CLO.
Now besides the dreaded bulk monster... you are almost exactly double on the ounces too.
My chart from above does not do a good job of addressing the CLO issue at zero and below. Essentially at those temps, the thermal gradient of your insulation is what breaks down the linear CLO formula. Simplest way I can think of it... it's like sitting around the fire at some point. At the right temps; we can warm ourselves at the fire pretty well. At really cold temps... no matter how hot the fire it's not enough to overcome how cold the side away from the fire is.
I would further point out a pet theory (most of what's above is pretty solid and agreed upon despite me being a carpenter and not a scientist)...
I find with under quilts specifically, which are products that have never truly been evaluated by industry or labs, that you need a different chart. I first discovered the problem with my air pads which I had hundreds of nights in proven conditions fail me at much lower temps in the air. I believe there is a similar loss for all insulation though I do not have that quantified nor do I have the decades of air experience I have on the ground personally. I do think it is important to note: nearly all the science is based upon top quilts (sleeping bag) insulation. That said... I put my money on field experience and customer satisfaction (which all the good vendors here have) which is why I'd prefer to see some of them make charts... but can't begrudge them for giving up that info as it didn't come free to them so I can't expect it to be given free to me.
None of the vendors here have joined in to discuss that issue. However, a pretty smart fella I know better from his time at BPL doing DIY started a business and has become somebody who's reputation in the backpacking world is starting to cross over into hammocks does share something subtle that many may have missed in his specs that backs this idea up.
So if you compare apples to apples (same vendor, similar techniques and calculations): you can look at his top quilt and his bottom quilt and see that starting around zero, he uses a slightly different loft value to reach the same spec.
https://support.enlightenedequipment...2284868-Revolt
https://support.enlightenedequipment...628-Revelation
To be fair... their UQ is a karo step... some calculate their loft differently for that baffle design. But either way... even if you didn't have the specs or a vendor... there are enough field reviews from users here and other places who give lots of testimony to using mixed combos for ideal comfort. Like a zero UQ and 20 TQ for 10* or "getting away" with that setup at close to zero despite the 20* gap in insulation up top. I think it's something we all know and understand, but it's hard to quantify. In part; to be blunt- HF crowd isn't BPL. Which is good. On the slightly bad side for science, charts, specs and formulas... when you build 10-15 degrees in "just in case" and toss in a few ounces overstuff just for safety... well it's hard to say exactly how much was needed.
Just for fun... my current theory is to take the loft chart from before for top quilts and add 5* minimum to achieve the same rating in an UQ... this appears to match what Enlightened is doing.
In synthetics you need to add 10*, in typical inflatable pads- 20*. This appears to be matching my testers field experience as I work on PLG UQ's... But it is quite clear that a 45* TQ is not a 45* UQ simply because you put it under the hammock instead of on top.
Further astute observation (said in my best Grizz voice) would also show that EE does not produce the Apex gear they sell below 20*
https://support.enlightenedequipment...68-Revolt-APEX
SO>>>> long story long: I can't really encourage or recommend that you build an Apex quilt much past 8 oz. It's your gear and your money, and some here have... but it doesn't work out right on paper or in the field that I could ever see. At some point, without baffles or extreme differential cuts, you are likely to crush out some of the insulation too. If you did... I think that loop quilting is the way I would go. And at those thicknesses I would use no more than 5oz batts and I would do the math to make them differentially cut. Down is much more forgiving... even if it doesn't seem that way. At depths of 3-5" especially.
PS- many of the deep winter folks I respect use foam for Under... I think they are on to something.
Grizz brought a very interesting quilt stack to a local hang here for 1* lows but not my ideas to share.
Why did you mention using multiple quilts rather than one thick one? What's the advantage there? Seems like that would add unnecessary weight, what with the extra shells, suspensions, etc.
Two things-
Stacking layers of batting inside a quilt. For Apex, they should be differentially cut. For PLG; the thicker the batt, the more loss of value during quilting. So two 3 oz layers (one quilted to each shell of the quilt) are warmer than one 6 oz layer because of loss of loft at each stitch. Same with two 4 oz vs one 8 oz (if you could buy it.) That said... that is what I consider the limit of PLG use. Double 4 oz. will get you around 5-15. Double 3 oz will get you around 25-35
Stacking finished quilts-
Enlightened should get credit for one of the original formulas published (though I can't find the link).
Basically they use 70*-(quilt being stacked's rating)= how much it will add. So if you have a 50* TQ, then it will add (70-50) 20* if you stack it over another quilt.
The advantage here... most of us don't winter camp that much... or own a dedicated winter set. And when we do winter camp we aren't that worried about miles, weight, or even moving much.
So if you own a 40* and a 20* and could stack them together to get to -10 (or so) then that's a pretty good deal right?
I am finding in practical use, to take 10* off that formula past zero. (70-45=25* added to my 25* quilt for zero) So I might stack my 45* PLG with my 25* PLG, but in real life it got about 10*. Which I feel pretty good about overall because now I can go back to my chart and see I added my 45* (3oz PLG) to my 25* (two layers of 3oz PLG) for a total of 9oz PLG which matches up pretty well with my chart and does back up my field adjustment to the CLO formulas past zero. That said... that trick don't fly on the UQ side.
However one neat thing:
Remember that thermal gradient thing (standing around the fire). Well if I just had a pure 3.5" of down top quilt... in reality the first 2.5" near me would be warm (near the fire) and the outer 1" of down would be about the same temperature as the air. So as my warm moist air moved from my body through my bag... it would cool. And when it's truly cold out... at some point it will be below freezing WITHIN my quilt. Which is okay for a day or three...
But if I were to say... have 2.5" of down (25*) but put a 45* PLG top quilt (or other synthetic) over that... Well now I'm pretty good to zero, but as the vapor cools in my stack of insulation it is either going to freeze on the inner shell of my synthetic (which I can then dust off as frost) or it will end up inside my PLG quilt. BUT... my down, my critical piece of insulation will stay pretty moisture free and working for many nights.
That's not to say that a VBL might not be the better choice (different debate) but that stacking synthetic over down has interesting properties and advantages beyond simply using one or the other.
Whooo Buddy... time fer a breather.
Wow @Just Bill
You are like the Alton Brown of quilting! Thanks for the detailed response.. Many things I was wondering about you touched on!!
Deja Moo: "The feeling you have heard this bull before"
What's funny is if you talk to any seamstress, sewing contractor or similar professional they'd look at you cross-eyedWow @Just Bill
You are like the Alton Brown of quilting! Thanks for the detailed response.
It takes me a long time to discuss quilting with them... they want to pinwheel fat quarters and all sorts of silliness and don't realize I just want them to sew things.
Thanks for digging this up!
Link is the quilt stacking article/chart/formula I mentioned above for everyone else. Worth a read.
I am both grateful and massively humbled by the brain power.
Happy Trails to one and all.
Enjoy the outdoors wisely and elevate your perspective.
Modified Penny Wood Stove instructional Video-http://www.youtube.com/watch?v=0fPlHqsYy38
Hammock Wheel https://www.hammockforums.net/forum/...09#post1035609
Another Really cool JC Penny Puffer instructional- https://www.hammockforums.net/forum/...141#post953141
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