Alas Poor Thermarest

[MuddyWaters]

It was fabric pulling away from the foam--and foam pulling away from itself. In effect, the foam itself has little holding power---like wet tissue paper---and so any outward stress causes the foam to separate---and so goes the fabric.

Once a failure begins, pressure retaining stresses are concentrated at the edge of the bubble, instead of across whole area, and it continues to peel away rapidly.

The force = pressure x area is increasing by diameter squared, the holding edge is is only increading proportional to diameter. Bigger it gets, less pressure needed for it to continue to get bigger.

In other words, self destructs as soon as tiny failure starts. The localized stress ripping the foam /laminate apart is many x normal design once a blister starts. UL open cell foam not that strong.

[Bronk]

There are very few pieces of gear that will last forever. I once had a tent that had seen over 700 days in the field and I felt like I had gotten far more use out of it than I had any right to expect by the time I finally retired it. I have a few pieces of gear and clothing that are 15+ years old, but I expect to replace most of my stuff every 5 to 7 years and I camp between 30 and 50 nights a year.

[Bronk]

Once a failure begins, pressure retaining stresses are concentrated at the edge of the bubble, instead of across whole area, and it continues to peel away rapidly.

The force = pressure x area is increasing by diameter squared, the holding edge is is only increading proportional to diameter. Bigger it gets, less pressure needed for it to continue to get bigger.

In other words, self destructs as soon as tiny failure starts. The localized stress ripping the foam /laminate apart is many x normal design once a blister starts. UL open cell foam not that strong.

I agree with this assessment and wonder if the pad could be saved if a repair were attempted when the bubble is small by applying heat to try to melt/re-glue it before it got too big.

[nsherry61]

Two thoughts on the cause of failure discussed above.

1) Of course, these pads are liquid proof if they are air proof . . . sort of, but, just like the deterioration of old urethane coated waterproof nylon fabrics happens when stored for long periods of time in a damp environment where the urethane coating starts to hydrolyze, skin oils can start to break down fabrics and/or lamination materials on fabrics over time even if the "liquid" does not flow through easily on a day-to-day time-frame.

2) As for delaminations occurring at shoulders instead of hips where there would theoretically be more pressure, there may be more pressure on hip bones than shoulders, but the upper part of the pad sees a whole lot more shoulder and elbow movement over an average night's sleep. I may shift from one side to the other - one hip to the other - several times throughout the night, but I reposition my elbows and shoulders hundreds of times a night. So I suspect that frequent movement of pressure points may cause greater risk of delamination than higher pressure pressure points.

3) Finally, as suggested earlier in this thread, there is probably a lot of truth to the idea that pads with less surface area for adhesion of the different layers of the pad to each other will lead to more frequent failure. So, it is reasonable that a pro-lite pad with gaps in the foam will delaminate easier than a pad with a solid layer of foam. But, the solid foam pad will of course be heavier and compress less. It is also reasonable that for a pad with baffles, more smaller baffles may hold up better than fewer larger baffles?

[brswan]

Is this just a recent thing? Think quality has gone down hill?

[Just Bill]

I know you had a bad first date; but I've been impressed with the Exped pads thus far.
I believe we're three generations in now and I haven't heard many busted baffle issues come up. So the kinks in the heat welded process (or whatever they use) may have been resolved.

Unlike the pure air based Xlite or Xtherm, the Exped uses a knock off of Primaloft Gold. So even if you did get a leak or a bust... provided you could get it to hold about 3/4" of air you'd get nearly the full R value of the pad in a pinch. Most field patches or tenacious tape repairs will do the job well enough to inflate to half full.

The pack size and weights are competitive with the neo-air series and they do make a wide medium which is nice. No short wide though.

Specifically the Hyperlight series, which does have a winterlight (not down) version to compare to the Xtherm.
Orange for three season, Red for winter.

The other bonus in my opinion goes to what Alligator and others discussed- inflation. The schnozzel system is pretty good (and if it fails you can always blow it up). It's very fast and it eliminates any moisture induced bacteria, mold, mildew, whatever type problems.
It's personal preference really- but the vertical baffles and thickened edges fit my style better and give me more usable pad than the Neo-Air design so slide offs are virtually non-existent.
I might suspect that your Pillow failures might be simply how you use the pad as far as repeating the location of the failure and given your time spent on it sitting, lounging, reading, etc. But that's not really important... just a matter of curiosity on why your failures occur in the same spot. Do you read on your side propped up on an elbow often? Or sit that way in your bag while you cook, etc.

On the durability... I believe we've had this discussion before. Had it at WB for sure...
I think better these days to discuss things in terms of 'nights' generally. Having run into this with SUL or UL gear being 'less durable' the argument is easily made that conventional weekend warrior or boy scout wisdom on years of durability of certain gear is simply a function of more folks doing LD hikes or spending extended time out like you do Walter.

A dedicated weekend warrior getting out once a month for two nights racks up 24 nights a year. So when that gear is claimed to last a decade... well it made it 240 nights. If a decent UL piece of gear gets through 1 or 2 through hikes or makes it for a year or so of 21 days at a crack per month then more than likely it saw more nights of use than 'Old Faithful' that was stored properly, cared for, and loved over a decade of weekends.

Continuous field use, daily packing and unpacking, temperature extremes, dirt, dust, body oils and on... 300 days of steady use without a serious issue is a pretty solid piece of gear in my book.

If that old faithful piece of gear was set out on the porch every day exposed to the elements by the weekend warrior instead of stowed in good condition even he'd probably see a few years taken off the lifespan if it didn't flat out dry rot long before 100 nights of use were achieved.

Not saying stuff should crap out; but just to keep some perspective (as I know you have) on durability.

I've been looking at a 100 night system myself...
100 nights for SUL/FKT minded gear... not throwaway but meant to do a specific job and a serious trip at the bare minimum of specs.

200 nights- solid gear to get you through an average Big LD hike or several LASH's. But not overblown 'bomber' stuff designed for the zombie apocalypse.

300 nights- pretty bomber stuff IMO. Several pieces of UL gear like packs and sleeping quilts hit this mark even without being too overblown in design with moderate care.

More'n that... well those are those rare pieces built for death and destruction and reflected in both weight and cost...
Like a Mystery Ranch Pack

[nsherry61]

Is this just a recent thing? Think quality has gone down hill?

Delamination of inflatable pads is NOT a recent thing. It has been with us since the beginning, and I'm going back to both my 1979 Termarest and my 1981 Termarest, both of which were eventually replaced because of delamination, admittedly after many years of weekend and occasional weeks of use.

I think that ultimately, as expressed by Just Bill, we are, to some extent, victims of our overblown expectations. We want light, reliable, and cheap. Reality will generally only give us two out of three of those. Pick the two most important to you and run with it.

Lastly, if we are pushing the technology envelope in design and materials, we will inevitably have a higher failure rate than continuing to use, and accept the limitations of, the old reliable stuff

[Just Bill]

Yar... nothing super new.
Though in my spunky years as a quartermaster for a 60 scout troop, gear repair guy and gear salesperson for scout troops and at a few retail places from around 1990-2000:

What I recall were valves and the occasional end seam on the thermarests. As Walter mentioned it wasn't until the die-cut foams of the thin-light series came around that these type of de-lam (or foam breakdown) issues popped up.

The foam and shell were never mated together if I recall correctly. The foam was simply cored out with horizontal channels and slipped into the heat sealed sleeve of the shell. Basically a pillow case system or a big water bladder.
So other than a puncture (easily patched) it was valve failures 90% of the time or the occasional edge seam breaking. I'm old enough to remember the brass valves falling prey to the lug monster boot as well killing off valves being an issue. Or the o-ring in the brass valve needed replacement/lubrication as part of repair.

REI and most therma-rest dealers carried valve repair kits... these days I can't recall seeing one or talking about it much. If there were forums in those days we'd have seen plenty of threads about replacing valves... since we don't now- I'd guess that's a problem they have mastered.

Therma-rest does/did seem to have the advantage in the pure air pads... but others are catching up on that as well.

So I'd guess these birthing delam bubbles may lead to the impression there is a slide in quality- in reality it's a newer issue related to pushing for lighter and lighter versions of pads and trying to laminate ever more delicate/lighter foam.

[martinb]

I had four Exped synmats delam, each after ~ 100 nights of use. I asked CS what the problems were with these and the response was part design flaw, part construction flaw. Supposedly their 3D pad solves it. I got one as a replacement for a delam, so far no issues but I've only used it a a few nights. Exped has been excellent with replacing these but there's still a fear factor when out on a multi-day hike.

[Tipi Walter]

I found this pertinent video link in a recent email and it's very relevant to this thread! Go thru the vid towards the end to see the problem---

[johnspenn]

I found this pertinent video link in a recent email and it's very relevant to this thread! Go thru the vid towards the end to see the problem---

Saw that one today too. Not sure why he bailed on the whole trip, he could have hiked back to Hot Springs and gotten something to get him through. Not that he needs my advise haha!

[saltysack]

I found this pertinent video link in a recent email and it's very relevant to this thread! Go thru the vid towards the end to see the problem---

I thought of you when I saw his vid yesterday....but you would have had a spare and kept truckin...


Sent from my iPhone using Tapatalk

[camper10469]

Okay boys, another one bites the dust. This is about my 10th or 12th delamination in the last 40 years sleeping on Thermarest pads.


Zoe dog investigates the sad Fact---welcome to Cascade Designs.


After a couple hours in the sun the pad DOES NOT self heal and instead expands.

I spent last night in the backyard "camping" and preparing for another trip and working out the kinks in my gear. Lucky me this happened before the trip.

thermarests are waranteed for life. return it and they will send you a brand new one.

[Tipi Walter]

I thought of you when I saw his vid yesterday....but you would have had a spare and kept truckin...


Sent from my iPhone using Tapatalk

Having a Plan B when it comes to a sleeping pad is required. In fact, I carry a ccf pad along with my inflatable in case the inflatable dies. And also carry a small and very light NeoAir as an emergency second backup but unused as of yet.

thermarests are waranteed for life. return it and they will send you a brand new one.

They probably won't cover what I did to the pad AFTER it delaminated.

[martinb]

This past weekend.

pad2.JPG

Are we having fun yet?

[Tipi Walter]

This past weekend.

pad2.JPG

Are we having fun yet?

Welcome to the wonderful world of Surprise.

[rocketsocks]

This past weekend.

pad2.JPG

Are we having fun yet?

Hold the air valve between your thumb and forefinger and have your pad turn it’s baffles and cough twice.

[Tipi Walter]

Welcome to the wonderful herniated world of ruptures.

[martinb]

This is the fourth synmat 7 (I originally bought two) that has done this on me. This latest failure was a replacement pad for one of the originals that failed. Exped has replaced the previous ones and I just mailed this one out yesterday to a probable replacement, as well.

This particular model is no longer produced, according to Exped, and I got a 3-D model for my last failure which hasn't had a problem, but it's real early. The older synmats failed in the 60-night range.

[martinb]

Hold the air valve between your thumb and forefinger and have your pad turn it’s baffles and cough twice.

I'm going to blow it all the way up and see if there's a late entry slot in the Macy's Thanksgiving Day parade.