High Sierra Topix

One hip felt a slight difference in temp than the other side. I was using a 1/2" closed cell pad and I had some melting under me. I would bring an extra pad to use as back up if your test did not work out using such a thin pad under the NeoAir. My setup did not save much weight, as the blue pad weights 13 oz. and the NeoAir was 9 oz. My Exped Dam9 comes in at 27 oz. I think.

hikerduane wrote:High. We need some engineer to do the calcs on this, to see how much pressure I was creating by blowing the pad up as much as possible, then standing on it with the 2X6 board with my 160 lbs. The board in question is 21.5 inches long, just as wide as the pad. I need to see now if I can repair it, wasn't thinking along those lines last night or this morning. I don't even think a repair kit is available for it yet. I will email Customer Service at Cascade Designs, as Sales has no clue what a NeoAir is. I thought that was hilarious when I emailed Sales and they went huh?

I just couldn't stop myself from applying some forensic structural engineering to this product failure. Based on physics, you didn't add any significant "extra" pressure to the mattress by distributing your weight on a 2x6. Because the chambers are all connected, the pressure inside the mattress would be the same if you laid on your back or your side on the mattress or used a board to distribute your weight. There could be a slight delay in balancing the pressure if the air movement is constricted between the chambers, but eventually it will be about the same no matter how you apply your weight. Try squeezing a balloon in your hands and you'll see it doesn't matter how you squeeze it as long as the force (your weight) is the same.

There are a couple of unusual conditions that could occur. If you "bottomed out", then some of the load would be carried by the ground and the net pressure increase would actually be less. If you applied the load very rapidly, then the pressure might not balance between the chambers quick enough in which case you would see a temporary spike in pressure. You didn't mention jumping on the board so lets rule that out. The take-away point is that the mattress did not fail because it had too much pressure. It did not explode.

However, there is an important difference between laying directly on the mattress and putting your weight on a 2x6. The edges of the 2x6 will cause local shear stress concentrations to the mattress fabric that you wouldn't get by distributing the load more evenly (i.e. laying on it). Having the mattress fully inflated would increase these local stress concentrations, as would any movement of the 2x6 or the mattress. You mentioned lifting the mattress to see the under side while standing on the board. The fabric shear stress concentrations are probably what caused the 3/8" v-shaped tearing damage you describe. I suspect that the tear occurred near a corner of the 2x6 as you were lifting the mattress.

These mattresses probably have a good safety margin built in against explosion, with the seams being the weak link. Its the fabric tearing or puncture that you need to protect against. Having written that, a fully inflated and heavily weighted mattress will be more prone to tearing or puncture.

I'm glad they replaced your NeoAir. I think I'll stay with my Prolite3 or 4 until I hear some long term success with this one. Saving the ounces is tempting though...

ok.. so I did buy the NeoAir L and it was great. for 10 days in the backcountry, before it started it's leak.. I didn't look for the leak, but it's been on either a tarp or in a tent the whole 10 days.

I love the thing when it works. And it's current leak puts my hips on the ground at about 3am.

bought it at REI.. guess what's getting replaced before my next trip in early Sept.

Thanks for the 411 Russ.
This seems to be an issue that I read about, but as usual it is hard to know whether
a lot of people are experiencing this, or just a few, and then people pass it on, and it
becomes a bigger issue than it really is.

don't get me wrong. I'm going to replace it via REI. It's really nice if you protect it.. not sure why it leaked.

I hear the Exped leaks as well (Mike). In our last "backcountry meeting" 3 mattresses leaked/failed.

TehipiteTom's "mattress" held up because it's closed foam. not that i could sleep on that again, but to each their own.

I have used a closed Washington Pad that I cut down to the contours of my body
to shave off even more weight, but on some trips some thing a little more cushy would
be nice, but not if I have to worry about leakage, especially at that price.

After finding a leak I returned my NeoAir and bought two Prolites (sz small) for me and the wife. About 2oz heavier. But considerably cheaper, and no leaks...yet.

Eric, a leak from a seam/weaker/lighter materials, or a puncture/abrasion or what?

rayfound wrote:Eric, a leak from a seam/weaker/lighter materials, or a puncture/abrasion or what?

I never was able to precisely locate the leak, although I suspect it was a side seam. To my chagrin the leak revealed itself on the first night of a four night trip (@ ~2am), so as you might expect, I was NOT a happy camper by the final day of the trip. In fact, before even driving home, I stopped at the local REI and returned the NeoAir. I think reading all the reports of leaks, experiencing one personally, and the fact that it was such a pricey pad to begin with, made it easier for me to decide on the spot that it just wasn't the pad for me.

" I think reading all the reports of leaks, experiencing one personally, and the fact that it was such a pricey pad to begin with, made it easier for me to decide on the spot that it just wasn't the pad for me."
Eric, if memory serves , I came to the same exact conclusion here last year...Light but too flimsy.
I wrote, "Seemed very thin/ fragile - thought dangerously so. (easily pop-able?) field fix questionable....especially if punctured down in the tube area."

Just because it got all the big hype, that does not make it dependable, (or trustworthy). Everyone I know who bought one and has used it hard for over two weeks, eventually says the same thing.

Maybe the next generation will fix the flaws. Until then my Prolite 4 (@ only 2 oz more) works just fine.

Mark