View Full Version : Neoair sleeping pad durability
Hello there.
I'm trying to decide if I should by the Thermarest Neoair or ProairPlus. Does anyone have any longterm experience with the Neoair? I'd like to buy it, but I'm worried that it will pop in the middle of the woods and leave me stranded without a sleeping pad...
-triacup
Big Dawg
10-28-2009, 10:13
search "neoair" on this site,,, other threads should answer your question. I'll own a neoair as soon as I can part w/ that kinda dough.
The neoairs have not been around long enough to know long term durability. Seems like I have read that a few people have made long sections with them with no problems.
There is a warning label that comes with them stating ultralight blah blah and so forth.
I think if you dont abuse them and use a thin bottom pad for extra protection you shouldnt have any problems.
Thermarest is a good company and will stand behind their products for defects.
Tammons is exactly right.
I used a NeoAir (with a Gossamer Gear thinlight pad underneath) from Damascus through the remainder of my thru hike without incident. It is a WONDERFUL sleeping pad!
take-a-knee
10-28-2009, 11:08
Tammons is exactly right.
I used a NeoAir (with a Gossamer Gear thinlight pad underneath) from Damascus through the remainder of my thru hike without incident. It is a WONDERFUL sleeping pad!
But still not nearly as comfortable as a hammock.
I have one and have used it in the field 3 or 4 times. I love it, but obviously you have to careful with sticks, thorns, cactus spines, etc. Puncture it and you have a $150 ground cloth. So far mine is working well.
By ProairPlus I gather you're talking about the Prolite Plus. My girlfriend had a bad experience with the Neoair in an EMS store, it popped and deflated right when she was trying it out. Seems there was a loose staple on the floor..... Completely turned her, and myself, off from buying it. For me it would have been more of the non-self inflating issue originally, and leaking issues I've read in reviews.
She ended up with the womens Prolite Plus and is much happy with the cushioning, warmth, and durability.
I currently have the Prolite 4( the old version of the Prolite Plus) and for the weight, refuse to give it up. I'm as happy I am in my own bed, almost, and unless it's freezing or below, it's the only pad I need.
But still not nearly as comfortable as a hammock.
but if you use it IN a hammock...:-?
I'm a hammocker, but prefer pads to underquilts. Underquilts are lousy for sleeping on the ground. A neoair might replace my BA someday.
take-a-knee
10-30-2009, 16:43
but if you use it IN a hammock...:-?
I'm a hammocker, but prefer pads to underquilts. Underquilts are lousy for sleeping on the ground. A neoair might replace my BA someday.
That would be tits on a boar-hog, apart from the warmth factor. Evazote is lighter, warmer, cheaper, and "flat resistant"
Ladytrekker
10-30-2009, 16:51
I am hoping that it does, I have used mine 5 or 6 times now and I love it. I do however, carry that really light pad you buy at wally world and put my neoair on it so that it does not get anything sticking into from bottom of the tent. And the cheap pad gives me something to sit on at stops. I feel mine all the way and then lay on it and release air until I get to fit just right and it is comfortable and it is not cold. I am really hoping for a long life with it.
socalhiker
11-25-2009, 22:23
My NeoAir short made it through 15 nights hiking the JMT this past summer. This was somewhat surprising in light of my T-Rest Prolite 3 that refused to hold air.
ShelterLeopard
11-25-2009, 22:45
Mine is on my Christmas list, and if I don't get it, I'll buy it the next day. Love it! And it has a life time warantee. And if you get a thin sheet of plastic to go under it, it should be fine.
I was thinking of a piece of tyvek under it.
I was thinking of a piece of tyvek under it.
That's what I use. As agroundcloth under the tent so there are two layers between the neo and the ground and on top of the floor or platform while in a shelter.
Barbarosa
11-26-2009, 11:27
Used polycro under mine for protection while doing a 3 week section this fall. Slept great, did however develop a slow valve leak. Returned to REI and have another one now. IMO best comfort for the weight on the market makes it worth the trouble of babying it.
Two Tents
11-26-2009, 11:42
I have around 20 nights on my Neo. I don't use a ground cloth just the floor of my Tarptent. If you have ultra lite gear then you are probably used to taking care of fragile type stuff. I haven't babied it more than any of my other gear. I know I'll buy another if I have to. The comfort level is up way there. No regrets.
paintplongo
11-27-2009, 14:30
I used mine for 800 miles this summer with no problems..
MuffinMan11
11-28-2009, 22:39
I have used my Neo Air for about 10-15 days so far, about 3 in shelters and the rest in a tent. The last two nights I woke up to the bag being low in the middle of the night. Not flat just a little low, I am not sure if it was a slow leak or just the weather that caused it to get low due to the drop in temp over night. In my tent I do use a thick ground cloth and it is also in side my Big Agnes sleeping bag sleeve. As for the the reflective thermal properties of the bag I cant say its all cracked up to be for cold ground temperatures. I sleep very cold and need a much warmer bag than what they are rated typically. Experience with a couple North Face bags and Big Agnes bags. The last two nights I used a 15 degree BA Ranger bag with my Neo in 38 and 42 degree overnights. Dont know if it was a combination of the Big Agnes and Neo Air or what but I definetly had some coldness from the bottom. I will be getting a very thin and lightweight foam pad to add to my bedding for the next time I go out to see if that helps the cold issue. I know it will definetly help with protection of the pad though. I will say I have never had much luck with the typical thermarest and always managed to have leaky and punctured pads over the last 10 years. But I still cant stand to just sleep on a foam pad.
JoshStover
11-29-2009, 00:42
I was planning on using the Neoair on my thru but after talking to several people who thru hiked this year with a neoair part of the way, I have decided to just go with a good ole Z-rest. It will never go flat. It might not be as comfortable but I like the fact that I will never wake up with a $130 ground cloth. The two guys I talked to said they loved them at first but got tired of not being able to just throw it down and sit on it anywhere. They both developed leaks and one of them got punctured to bad to repair on the trail. I think if you are just doing some weekends they would be the ticket but Im not sold on them for the thru.
MintakaCat
11-29-2009, 06:26
The last two nights I used a 15 degree BA Ranger bag with my Neo in 38 and 42 degree overnights. Dont know if it was a combination of the Big Agnes and Neo Air or what but I definetly had some coldness from the bottom.
I think the problem is the Neoair in that case, the specs state that the R-Value is only 2.5. Compare that with an Exped Downmat 9 which has a R-Value of 8, and weighs a lot more too.
I like the Neoair but if I get one it will be for warm weather only because of the low R-Value.
MuffinMan11
11-29-2009, 09:26
I think the problem is the Neoair in that case, the specs state that the R-Value is only 2.5. Compare that with an Exped Downmat 9 which has a R-Value of 8, and weighs a lot more too.
I like the Neoair but if I get one it will be for warm weather only because of the low R-Value.
Good to know, I had never known about the R-Value rating before, but it had never been an issue until recently.
The R-value issue has been discussed a lot, at least on other forums, without huge consensus being formed. Your metabolism is a factor, as is the totality of other warmth factors (clothing, sleeping bag, tent), but indeed a person can have plenty of insulation elsewhere and still be cold without enough ground insulation.
It's also been suggested that it's important when folks are talking about "how cold it got and how cold or warm I was" that they measure the temperature right at ground level.
Bottom line is that it seems like some folks are saying they're fine with a Neo-air down to freezing, and can take it lower with some sort of ccf (closed cell foam) pad to augment, others think more like MintakaCat that a lot more R-value of padding is needed.
I'll combine Gossamer Gear thinlight pads and the neo-air for my late Feb start on the AT, and just send one of two thinlight pads home when things warm up, keeping one to put under the neo-air for the entire trip to reduce the odds of getting holes in it. A similar strategy with a ccf pad and different inflatable worked out fine on the PCT in 2008, no leaks. I think the only way to know for sure how much and what type of ground insulation is sufficient for you is to test it out in field conditions as similar as possible to what you might encounter.
GeneralLee10
11-29-2009, 11:15
I don't understand
Why would one want to buy a sleeping pad to save weight. Then in return purchase another pad or two pads to carry along with the the lighter pad. How and where do you save weight and space doing such a thing. Maybe one of you can help me on this.
ShelterLeopard
11-29-2009, 11:51
Because the neoair is very light an compact, and the reason I want it is comfort, and packability and weight. Comfort is first on the list. And I'm not carrying anything to put under it.
ShelterLeopard
11-29-2009, 11:52
And the second mattress people usually carry is very light, very cheap, and something they don't really care about.
Similar to what ShelterLeopard said, plus there's some flexibility in carrying the combo ... I'll start with a Neo-air size regular plus both 1/8" and 1/4" thinlight pads from GG. I can add or subtract thinlight pads to tune my total padding weight to the minimum that keeps me reliably/safely warm enough (i.e., mail a pad home when I don't seem to need the thermal boost anymore).
And if I get a leak (that I can't fix), I'll at least have some padding --- thinlight, plus 2/3 of a GG "nightlight" pad that doubles as back padding for my backpack.
I'll keep at least a 1/8" thinlight pad throughout just to improve the overall durability of the system, and I might well keep the 1/4" thinlight instead --- 3.5 oz vs. 2.2 oz, more protection for the pad.
The neo-air isn't just about weight, it's about trying to hit a sweet spot between comfort, weight, and R-value, while also considering other factors like durability, $$ cost. These latter three are issues with the Neo-Air, the weight plus comfort override for me --- I think. If issues arise, I'll switch back to the system I had been using.
Sorefoot, I guess another way of responding to this is to consider the alternatives. For example, an Exped Downmat 7 is listed at REI as weighing 31.7 oz with an R-value of 5.9. My neo-air size regular plus 1/8" and 1/4" GG thinlight pads all together weigh (gulp) 21 oz. Total R-value is something on the order of 2.5 + 1.4 = 3.9, substantially less warm --- but warm enough, I think, for the AT starting in late February --- based on my own testing in upper teens farenheit conditions.
Yet another nice reason for having the ccf pads is that they can make for a nice thing to sit/lay on at a break. A single inflatable is somewhat of an all-or-nothing proposition.
MintakaCat
11-29-2009, 14:25
Bottom line is that it seems like some folks are saying they're fine with a Neo-air down to freezing, and can take it lower with some sort of ccf (closed cell foam) pad to augment, others think more like MintakaCat that a lot more R-value of padding is needed.
Correct me if I'm wrong here but doesn't the R-Vaule go up just by adding a closed cell foam pad under the Neoair??? Or in your case, adding two Gossamer Gear thinlight pads?
That's three sleeping pads you're now carrying all to keep the Neoair, and at the same time you're questioning why I'm focused on R-Value while you're increasing your R-Value.
I guess I missed your point, because it seems we're both saying the same thing.:-?
MintakaCat
11-29-2009, 15:05
Okay Brian, I just saw your above statements and I think you were interpreting my statement as suggesting that Bobby use a Exped Downmat 9, and that he must have a maximum R-Value.
No, I was just saying that he needs to pay more attention to increasing the R-Value of his sleeping system if his current setup is not performing adequately. I was only pointing out where the Neoair is in the overall scale.
The R-Value of the Exped Downmat 9 is about the high end at 8, so he has some room for improvement from the current 2.5 since he has stated that it was not working out for him. No, I never said a lot more R-value of padding is needed, only that he needed to pay more attention to it.
And No, I don’t think anyone that would label themselves as an ultra-light hiker would be carrying a Exped Downmat 9, LOL.
I thru hiked the PCT this year and used the 72'' Neo Air, I did get two punchers but they were super easy to repair and it was not in the desert. The company PARK that makes bike repair tools, also makes a bike tube repair kit,which is very light. This is the old school type patches that use glue.. Got the info from Cascade Designs Customer Service, Don't let the fact that this pad is thin scare ya away, it is really easy to patch" In the Field". One hiker did have a problem with his leaking out of the valve but you know that could happen with any inflatable. I am a cold sleeper and used a 20 degree WM ultralight and stayed warm, for all but one or two nights that it snowed in Washington. And If you want to have some thing to sit on just cut a small section of some closed foam pad and carry that with you, Neo is great, and if you want to save Weight, get the 9oz 3/4 length..
A regular Therm-a-rest ridge rest weighs the same 14 oz as the Neo Air and has an R value of 2.6. it seems that the main advantage of the Neo is that is packs down a lot smaller.
Or is it really that much more comfortable?
way more comfortable if you are a side sleeper.
Chaco Taco
11-29-2009, 18:12
So I need to understand this right. Im supposed to carry my tyvek ground cloth for my tent, then another piece for under my pad????
MintakaCat said: "Correct me if I'm wrong here but doesn't the R-Vaule go up just by adding a closed cell foam pad under the Neoair??? Or in your case, adding two Gossamer Gear thinlight pads?
That's three sleeping pads you're now carrying all to keep the Neoair, and at the same time you're questioning why I'm focused on R-Value while you're increasing your R-Value."
I think we're all communicating well here --- indeed the R-value does go up, though perhaps varying somewhat depending on whether one or both ccf pad goes under or over the neo-air. Anyway, I wasn't trying to put words in your mouth or anything (sorry if it came across that way!). I just had the sense from an earlier post that you were more in the camp with those that favor a bit more R-value in cold weather than some others try to get away with (possibly to include me ...).
In terms of carrying 3 pads total, it's in fact a flexible approach, I would say "up to 3", more typically 2. In 2008 on the PCT I carried a torso-length Montbell inflatable, much much thinner than the neo-air, and I started out the trip with a full-length ccf pad underneath that, and it was generally just fine for me. But that shorter and much thinner inflatable was a surprisingly large percentage of the weight of a regular (full) length neo-air: 10.9 oz vs. 15.3 oz, for a delta of 4.4 oz to go to the Neo-Air and I save another 1.3 oz from less ccf padding even if carrying two thinlight pads --- the combo are the thickness of a single typical 3/8" pad, and shorter than the one I carried on the PCT. Drop one of the thinlights too and I'm essentially weight neutral for the swap (with quite a large gain in comfort/padding).
I had thought at some point in 2008 I might ditch the ccf pad (post-Sierras) and just use the inflatable, but by then I was pretty strong and just felt inclined to keep it for the extra padding and protection for the inflatable.
Anyway, each to their own, it's not about convincing someone else to change their mind or anything, just sharing ideas!
Chaco Taco said: "Im supposed to carry my tyvek ground cloth for my tent, then another piece for under my pad????"
Well, of course you're supposed to carry whatever makes most sense to you to carry (!). Whether you carry a ground cloth at all is a subject of another frequent debate; I will on the AT, as I'm going with a floorless tent ...
Carrying something else to help protect an inflatable mattress is something that makes me a little more confident. With a 3/8" ccf pad under my inflatable last year I had no holes for the entire trip, and in fact have never had a hole in an inflatable in a backpacking "lifetime total" approaching 4000 miles now. Who knows how much that's dumb luck vs. site selection & site prep vs. tent and/or groundcloth and/or ccf padding underneath inflatables that I've slept on however!
So I need to understand this right. Im supposed to carry my tyvek ground cloth for my tent, then another piece for under my pad????
NO,you need to spend the $ first...then see what you need.
MintakaCat
11-29-2009, 21:45
Anyway, each to their own, it's not about convincing someone else to change their mind or anything, just sharing ideas!
Agreed, I think we're pretty much on the same page on this.
Chaco Taco
11-29-2009, 22:37
NO,you need to spend the $ first...then see what you need.
I really like the specs on this pad. I just have not had great luck with Thermarest. But I just think its the way I store them off trail.
EMS has these onsale right now for a decent price online.
I just asked about carrying all of this extra stuff. it just seems so unnecessary to carry an extra piece of tyvek for a sleeping pad
ShelterLeopard
11-30-2009, 01:16
I just want it for comfort, and it's lightweightness. I couldn't care less about the R value argument. (Well, not really. When it gets into the tiny differences, I just couldn't care)
Hello there.
I'm trying to decide if I should by the Thermarest Neoair or ProairPlus. Does anyone have any longterm experience with the Neoair? I'd like to buy it, but I'm worried that it will pop in the middle of the woods and leave me stranded without a sleeping pad...
-triacup
Totally valid question, but the answer lies in as much, maybe even more, about how you use it and how you treat it, than just the NeoAir by itself!!! Hiking gear out on the trail Does Not exist inside a bubble by itself!
This is one of those things that should speak for itself. On the Thermarest NeoAir packaging and tags and at the several websites, where I comparatively shopped for my NeoAir Shortie, it states "this is an Ultra Lite piece of gear and should be treated as such." If you don't know what that statement entails or you disregard it and your pad fails don't blame it on Thermarest or the NeoAir!!!
Saying that, I recently used my Thermarest Neoair Shortie, on a 215 mile Sierra High Route thru-hike often sleeping on bare abrasive granite slabs with just this pad on the ground. I never plopped down on it. It's not designed to take that kind of abuse repeatedly. I also used it on that hike as a virtual framesheet(stiiffens my frameless ULA Conduit). NO PROBLEMS! So far!
My guess is that most of the AT has less abrasive ground on which you will often camp. However, it's an INFLATABLE mattress. Use it with some care!
ShelterLeopard said: "I couldn't care less about the R value argument. (Well, not really. When it gets into the tiny differences, I just couldn't care)".
I think you were the one that began the "Who's starting the AT in February" thread? If so, I suggest that you spend at least one night out if possible in temps of 20F or if possible somewhat lower with the same gear you plan to start the AT with --- and make sure to put your thermometer right on the ground when measuring the low for the night.
Maybe (hopefully) you'll be fine, but the difference between the R-value for a neo-air by itself and one with some sort of ccf pad on top is more than tiny; some folks have reported being too cold on a neo air in the 20's and up to freezing despite having an otherwise plenty-warm sleeping system.
ShelterLeopard
11-30-2009, 11:23
I think you were the one that began the "Who's starting the AT in February" thread? If so, I suggest that you spend at least one night out if possible in temps of 20F or if possible somewhat lower with the same gear you plan to start the AT with --- and make sure to put your thermometer right on the ground when measuring the low for the night.
Maybe (hopefully) you'll be fine, but the difference between the R-value for a neo-air by itself and one with some sort of ccf pad on top is more than tiny; some folks have reported being too cold on a neo air in the 20's and up to freezing despite having an otherwise plenty-warm sleeping system.
Yep, that's me. And yes, I have a serious cold weather shakedown coming up in January (in PA). I also did one in November, hoping it would be chilly- so much for that. Didn't have all the gear I needed anyway... But, I will in January and plan to do at least one two day gear shakedown.
I already have a good thermarest (self inflating), and if I decided that the neo air isn't warm enough, I'll either add a small piece of a ridge rest I have, or just take the self inflating pad until it warms up.
But, it shouldn't be a problem. I sleep warm and invested in some really nice long johns and am about to get some fleece as well. I have a pretty good winter selection coming. (Even considered the feathered friends down booties)
So, if it really turns out not to be warm enough on its own, I have plenty of options. Thanks! (I know, you didn't ask for a run down of all that long-winded jazz, but too late!)
ChinMusic
11-30-2009, 12:49
Similar to what ShelterLeopard said, plus there's some flexibility in carrying the combo ... I'll start with a Neo-air size regular plus both 1/8" and 1/4" thinlight pads from GG.
I think the combination of a regular Neo and a torso GG Thinlight pad makes the most sense. The Thinlight pad kicks up the R-value for colder nights. It helps protect the Neo. And it gives you a sit-pad as a bonus.
Again, JUST Buy the Neo Air, a patch kit, and get your self on trail, it will be fine. It worked for me and other hikers on PCT it will work on the AT. What will be nice is that all this gear worry and discussion will be non issues after a few weeks on the trail. Its one of those things you have to trust about hiking.
ChinMusic
11-30-2009, 13:39
Again, JUST Buy the Neo Air, a patch kit, and get your self on trail, it will be fine.
I think it goes without saying that if you carry ANY inflatable pad that you need to carry a repair kit as well.
I'm just surprised that such a kit, nor stuff sack, isn't included with the original purchase of the Neo. Both are included with the heavier Big Agnes products.
From that attitude that I have experienced from the Cascade Designs customer service rep, When I called this year from Mammoth Lakes. I am not surprised that C.D. does not include what B.A does... C.D. makes good products however.
MedicineMan
12-01-2009, 00:43
for those who do want to use a thin ccf pad to protect and enhance the insulation of the neoair check out:
http://www.40below.com/product_detail_public.php?ProductID=610
This is a 1/8 inch ccf pad. It weighs 9oz full size, 5 ounces cut to fit in the double bottom of a JRB Bridge Hammock, so 4-5 ounces for the ground dwellers. I used it with my neoair and it does fine protecting and helping with the R value...when cut down to 4-5 ounces it easily fits in the backpadpocket for a mariposa plus so it can be used as a sit pad too.
Cost around $7 to get it shipped though.
The 40below 1/8" ccf is an interesting option, one I hadn't heard of --- a little cheaper relative to the size that you get, and nice to have the option to start with a bigger piece and cut it to the exact length/width that you want.
But the Gossamer Gear thinlight (http://www.gossamergear.com/cgi-bin/gossamergear/thinlight.html) is listed as being lighter weight per equivalent size than the 40below --- about 2/3 the weight, even if use the 40below listed weight of 8 oz vs. 9 oz that MedicineMan mentioned above. And the GG site has a fair bit of verbage talking about how the process used to create their pads is superior, lighter/stronger per unit weight. For my use, I'm inclined to stick with the GG pad (besides, I already have it ...).
springerfever
12-01-2009, 17:53
shelter leopard......let me know what you think of the FF Booties if you get them. I think they have the best design (albeit a little more weight..in that they have the down bootie plus the overboot that can be worn in conjuction.) Perfect for a midnight call of nature. Plus the booties can be worn in your bag with no dirt/etc. Pretty neat design. Both Western Mountaineering and Nunatuk have similar designs, lighter, but without the inner/outer setup.
I've had my neoair large for about a month and used it for four nights on the southern AT. LOVE the comfort, but it takes a while to blow up. A large in 3/4 length would be perfect for me. All in all.......a great pad and no problems. Forget the $15.00 stuff sack. Yes it fits in the sack with no problem, but just roll it up tight and it will fit almost anywhere..it is so small. TIP... blow it up full, get comfortable and then slowly release air to reach the perfect support. AWESOME !!
MedicineMan
12-01-2009, 22:12
that 9oz was via my digital which aint exactly a high priced one...but on a per ounce comparison it's mighty close to the one we use here at work...I've got a Gossamer thin light as well and the Speer 1/4 inch, can't go wrong with any of them. The 1/8 inch was the key to finding a pad thin enough that it could fold enough times and still not be too thick in on the Mariposa yet still be big enough when unfolded to use in the double bottom Warbonnet or used if forced to the ground.
I'm thinking the NeoAir and GG Thinlight, maybe even further tweaked by cutting it down, may be my go to cold weather sleep pad set up for the CDT.
I haven't tried this yet with the NeoAir, as I have not experienced any failures with the NeoAir, but I got holes from Joshua Trees in my Thermarest Prolite 3 on the PCT and instead of buying and applying expensive Thermarest patch kits a dab of McNetts Seam Grip left to dry over night on pin prick size holes is all you need to fix those kind of leaks. I think the Seam Grip is easier to apply and looks better when fixed too.
MedicineMan
12-01-2009, 22:38
well if you carried a 1/8 or 1/4 ccf just for protecting the neo-air that would be one thing but since you can get several other uses out of the ccf why not...just dont be afraid to put the scissors to it. I'm thinking a ground dweller could whittle it down to 4ounces and that's head to heels and if you think you'd ever hammock with it leave on some wings.....
earplug94
04-23-2010, 23:16
Sold both of mine. Both leaked almost immediately. Not durable enough for me.
earplug
ChinMusic
04-23-2010, 23:26
Just bought a Neo and will be using it in May on a hike into Trail Days.
Any air pad can leak. It's the price one pays for comfort.
I have had to patch several leaks in my Big Agnes Air Core over the years.
You HAVE to treat is carefully. Stuff happens......plan for it.
FamilyGuy
04-24-2010, 00:35
Just bought a Neo and will be using it in May on a hike into Trail Days.
Any air pad can leak. It's the price one pays for comfort.
I have had to patch several leaks in my Big Agnes Air Core over the years.
You HAVE to treat is carefully. Stuff happens......plan for it.
I really like mine. No issues with durability. You may find that in large temp swings it seems like it deflates a bit (well actually does - i.e. Boyles Law) but for the weight, it is comfy as 'home.'
ChinMusic
04-24-2010, 01:10
I really like mine. No issues with durability. You may find that in large temp swings it seems like it deflates a bit (well actually does - i.e. Boyles Law) but for the weight, it is comfy as 'home.'
Actually it is Charles Law and not Boyles.
FamilyGuy
04-24-2010, 01:19
Yup
I get those two mixed up.
FamilyGuy
04-24-2010, 01:32
Actually, Boyles Law has an effect here as well:
Boyle’s law states that at constant temperature for a fixed mass, the absolute pressure and the volume of a gas are inversely proportional. According to the Standard Gas Law; if no other variable changes, a temperature decrease will result in a pressure increase and hence, a volume decrease. The pad deflates.
ChinMusic
04-24-2010, 01:43
We would be dealing with a variable temp. Boyles deals with a constant temp.
FamilyGuy
04-24-2010, 01:47
Yes but as the temp falls in comparison to the temp of the 'gas,' there is a pressure increase inside the pad, causing the volume change. Is this not the case?
ChinMusic
04-24-2010, 01:59
Boyles Law deals with a constant temp with volume and pressure as variables. Charles Law deals with a constant pressure with temp and volume as variables.
Under Charles as temp goes down volume goes down. In that case give it a few more puffs. You don't even have to know physics to come up w that solution.
Big Dawg
04-24-2010, 09:13
I just received an email this morning to come pick up my neoair from REI. They didn't carry larges in the store. Based on all the rave reviews, I'm pretty stoked about finally getting one! And if mine EVER has a leak problem, I'll just head back to REI and say... "this one leaks, may I please have a new one"!!! :D
FamilyGuy
04-24-2010, 11:43
Boyles Law deals with a constant temp with volume and pressure as variables. Charles Law deals with a constant pressure with temp and volume as variables.
Under Charles as temp goes down volume goes down. In that case give it a few more puffs. You don't even have to know physics to come up w that solution.
Both are taking place because the temperature in the pad is constant. It is the temperature outside the pad that vaires causing the pressure change.
In any event, have fun blowing it up - this is the only downside to the pad that I have found. At least 25 full blows.
But it packs so small for so much comfort it is hard to believe. For me, it has been suitably warm to 35 degrees but some have been chilled. A lot obviously depends what you eat before, basil metabolic rate, etc. For freezing and below (if I know beforehand) I bring an Exped DM #7. The Exped is still not as comfortable as the NeoAir for me.
ARambler
04-24-2010, 15:44
Both are taking place because the temperature in the pad is constant....
Stop, you are just digging deeper.
This is how you argue that it is a Boyles Law issue:
For the Neoair, the pressure stays pretty constant while inflating, and we could call this an "atmosphere+", just enough above atmospheric to raise the top of the pad. When the pad gets full, it goes through a short transition where a little extra pressure is needed to plump out the tubes. After that, the only way to get more air in the pad is to increase the pressure inside the pad. These are Bolyes Law operations. So the volume of air in the lungs plus the pad, gets compressed into just the pad, and the (absolute) pressure (ratio) goes up linearly with the total volume ratio=(pad+lungs)/pad.
Now, say you lay on the fully inflated pad and compress 1/3 of the pad. Further assume you compress the total volume by 1/9 (or the pad is 8/9 of the original volume). Skipping the algebra, the volume under your body will decrease by 1/3. What happens if the pad wasn't fully inflated to start? Say the volume of the 2/3 not covered by your body increases by 1/9 and the total volume shrinks by 1/9 again. The volume under your body will decrease by 5/9. Because your body is not flat, you may be bottoming out in this example.
So, Bolyes Law says that you bottom out because the pad is not inflated enough; if you are bottoming out in the morning, it is the same as if you were bottoming out the night before. When you get off the pad, and blow it up at night, it will be just as easy to blow up as when you set up camp.
Just because someone remembers the name "Charles Law", does not mean temperature is causing the problem. Likewise, being suspicious of science does not prove that the pad leaks. These are the two most likely explanations (of nighttime deflation), but there are others... (sliding down a 4000 ft glacier raises atmospheric pressure;). If you have to reinflate the pad more than once a night, it is probably a leak. If you wake up in a couple of hours, after the temperature has stabilized, and the pad is still pretty good, but then deflates by morning... you may have a leak. If you poke the pad with a thorn, you have a leak. If your pad was OK in the spring, but in the summer starts to deflate, you probably have a leak. I think/hope that the deflation issue is temperature related, because I bought the Neoair pad.
Note, it is easier to bottom out as the pad gets bigger, the sleeping area gets smaller (side sleeping?), or the person gets heavier (I don't know how to control this:( but it is a big help for a kid on a full pad). For example, if the person only takes up 1/6th the area and the total volume decreases by 1/9, the volume under the sleeper decreases by 2/3. This is why I bought the small (and the smaller pad is lighter, cheaper, and easier to blow up).
Rambler
FamilyGuy
04-24-2010, 17:37
Wow - now I know why they call you Rambler.
I suspect this is simply an example of where the air inside the pad contracts as it cools overnight. The pad does not go flat and there are no leaks. In fact, should the outside temps increase, there will be the opposite effect.
ChinMusic
04-24-2010, 17:52
Boyles Law more accurately deals with a leak in the pad.
Charles Law more accurately deals with a change in temperature of the pad.
Big Dawg
04-25-2010, 10:40
maybe we should have a separate thread about the differences between Boyles Law & Charles Law..... :rolleyes:
ChinMusic
04-25-2010, 12:18
maybe we should have a separate thread about the differences between Boyles Law & Charles Law..... :rolleyes:
But u gotta know these things or u won't be able to figure out u need to give it a few more puffs.
FamilyGuy
04-25-2010, 13:15
But u gotta know these things or u won't be able to figure out u need to give it a few more puffs.
Certainly if you are already full of hot air.
I love this technical stuff!