Investigating an Exped mat failure

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Investigating an Exped mat failure

Postby undercling-mike » Wed 30 May, 2018 1:54 pm

With all the discussion of Exped sleeping mat failures and given I have a failed one just sitting around I thought I'd cut it open and give it an autopsy/investigate the possibility of repair. My mat is a synmat winterlite that had about 25 - 30 nights use and of course it died a bit outside the warranty period. The baffle blew while turning over (not violently). I tried to use it carefully, i.e. be gentle, less than full inflation, use pumpsack for inflation, allow any moisture to dry from the surface before packing. I also have an original neoair from 2010 that has over 200 nights on it (I think well over), it's now stone cold I think because the reflective layers have deteriorated but that's another story, the baffles are still intact, so it was of course a bit disappointing to get so much less use out of the Exped.

Classic Exped baffle failure
sP1300037.JPG


Making the incision
sP1300044.JPG


So actually on inspecting the baffles it hasn't failed because of delamination of the weld between the baffle and the outside material, instead the baffle has torn. Close inspection shows that it tore right at the edge of the weld (the flap you can see still attached to the bottom (uncut) layer of fabric is the seam allowance of the baffle). The Baffles are some kind of plastic film and seem like they would be susceptible to tearing from any defect or weak point.
sP1300039.JPG


You can see where the baffle material tore around the end of the weld
sP1300041.JPG

sP1300043.JPG



From a first look inside the thing it seems like the baffle material itself is the weak point in these mats (at least from the same generation as mine) and durability could be improved substantially if Exped used a stronger material for the baffles. Not sure if I gained any insight into how best to avoid failure or what actions cause it, maybe it's just luck.

As for repair, it might be possible to re-glue to baffle with an appropriate glue then glue a strip of TPU fabric over the cut, hmmmm. I wonder what sort of glue would be best, Aquaseal, Seam Grip? It would probably take a fair bit of glue to re-seal.
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Re: Investigating an Exped mat failure

Postby Aushiker » Wed 30 May, 2018 2:56 pm

Thanks for the most interesting post. I just threw one out on the weekend ... wished I had thought to do this.
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Re: Investigating an Exped mat failure

Postby andrewa » Wed 30 May, 2018 3:03 pm

Maybe repair with double sided tape used for cuben seams? (use thin plastic to cover the unused "sticky" side of the tape - I'm amazed at how well such tape sticks.

Good dissection, BTW!

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Re: Investigating an Exped mat failure

Postby andrewa » Wed 30 May, 2018 3:03 pm

Maybe repair with double sided tape used for cuben seams? (use thin plastic to cover the unused "sticky" side of the tape - I'm amazed at how well such tape sticks.

Good dissection, BTW!

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Re: Investigating an Exped mat failure

Postby undercling-mike » Wed 30 May, 2018 4:32 pm

andrewa wrote:Maybe repair with double sided tape used for cuben seams? (use thin plastic to cover the unused "sticky" side of the tape - I'm amazed at how well such tape sticks.

Good dissection, BTW!

A


Using tape is a good suggestion and maybe a bit more practical. It might be possible to get the seam allowance flap involved to reinforce the join (so it's not just in peel). I'm also worried about sealing up the long cut needed to access the broken baffle, seems like it'd have to hold quite a lot of tension.

I'm kind of curious to see if it is possible to repair even though I wouldn't use it for anything too serious, probably just car camping, if I did repair it.
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Re: Investigating an Exped mat failure

Postby FatCanyoner » Wed 30 May, 2018 4:36 pm

Really interesting insight into why the Exped baffles fail. I gave up on them after having two lots fail in the same way (thankfully, the first was replaced within warranty). The second time I was incredibly careful, like you, and still the baffles failed. I never thought to look inside to understand the mechanism.

As for repairing it, I think you'd just be delaying the inevitable. Once your mat has deteriorated to the point one baffle fails, the others can't be too far behind.
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Re: Investigating an Exped mat failure

Postby Aidan » Wed 30 May, 2018 6:17 pm

I've seen lots of posts in various forums wailing the failure of certain camp mats.
I was under the impression that Exped offered a five year warranty.
Am I mistaken or are they particularly slack at sorting warranty repairs/replacements?

I ask as fearing imminent de-lamination some time ago, i bought, I think, a Sea to Summit mat.
Given that my Synmat 7UL is still holding air, might I have been too hasty.
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Re: Investigating an Exped mat failure

Postby GPSGuided » Wed 30 May, 2018 6:58 pm

Great investigation on the failure mode. Now we just need to see confirmation on this particular mode of failure from another one or two cases. Any one have another failed baffle lying around?

I notice in the last photo from Mike to show some form of manufactured hole at the end of the split. Mike, if you no longer want the mat, it would be interesting to see the exact design geometry of the same area elsewhere, before a failure. Was the split started from the round hole area? I assume the round hole is there to permit air transfer b/n baffles.
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Re: Investigating an Exped mat failure

Postby Nuts » Wed 30 May, 2018 7:07 pm

I'd send it back (even now).
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Re: Investigating an Exped mat failure

Postby undercling-mike » Wed 30 May, 2018 9:16 pm

FC: Yeah I get what you're saying about it not being worth fixing it, if I do try it'll be more out of curiosity than in the hope of getting use out of it.

Aidan: The ultralight range of mats have a 2 year warranty. As far as I know Exped will provide warranty replacements but I wasn't bothered raising a stink about this one out of warranty. Some people have had these mats last a good long time and there have been many failures so I was hoping to gain some insight into the cause of the failures and if there is anything that can be done to prevent them. I couldn't really determine why the baffle ripped, there wasn't any visual deterioration in the materials that caused it to rip, everything still looked good inside, except for the torn baffle obviously. I'm left with the impression that the baffle material is just a weak point and variation in production can make some mats more prone to having the baffles blow out. If you have a good one and use it carefully it'll probably last a good long time.

GPSGuided: Yep, would be good to see inside some more failed mats to see if the failure mode is the same. I think the last photo isn't super clear, the round hole in the baffle material isn't really a hole, it's where the baffle tore out at the end of the weld. The end of the baffle welds have a rounded teardrop shape and there's space at the head and foot of the mat for air to flow around the ends of the baffles.

Nuts: I see what you're saying but not sure I could be bothered dealing with it, I decided to forget about it and move on when it failed but the recent talk got me interested to have a look inside.
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Re: Investigating an Exped mat failure

Postby andrewa » Wed 30 May, 2018 9:54 pm

I have 4 of them and none have failed, beside getting a small tear in the outside.... poorly fixed , but desperately done, with a bandaid, and subsequently fixed properly With cuben tape patch.


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Re: Investigating an Exped mat failure

Postby Lizzy » Thu 31 May, 2018 6:27 am

I have 2 & both ok so far too- and that’s with kids!!
I also have 2 Thermarest neo airs that have been going for years :) (lots of touch wood happening)
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Re: Investigating an Exped mat failure

Postby Orion » Thu 31 May, 2018 6:38 am

I have a Thermarest NeoAir with a baffle failure. It's less than a year old. I already returned a second one with a blown baffle.

I wonder if it's the same mechanism of failure? Perhaps a bit of exploratory surgery and an attempt at a repair would be fun.
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Re: Investigating an Exped mat failure

Postby Nuts » Thu 31 May, 2018 10:55 am

I'd agree with that venture tape being a good choice, wouldn't the baffle tear/repair be forced on the joint in shear? (or maybe it broke too close to the join already?)

undercling-mike wrote: I decided to forget about it and move on when it failed but the recent talk got me interested to have a look inside.


Fair enough. I'd not suspected anything but the glue giving way, so it is interesting to see yours.

I cut some baffle from one and made it shorter but didn't check what gave way, the glue or baffle. These Synmats had a baffle material that looked much heavier, more like that of the grey base (pic 3):

Screen Shot 2018-05-31 at 10.42.53 am.png
Screen Shot 2018-05-31 at 10.42.53 am.png (569.64 KiB) Viewed 2319 times
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Re: Investigating an Exped mat failure

Postby Stew63 » Thu 31 May, 2018 3:38 pm

I've had 2 Exped mats.. First one failed after only a few nights (and only inflated to ~60%) and then the warranty replacement mat was already failed out of the box!
I now only consider Exped mats just expensive, disposable junk. Would never buy again...
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Re: Investigating an Exped mat failure

Postby Aidan » Thu 31 May, 2018 7:20 pm

undercling-mike wrote:Aidan: The ultralight range of mats have a 2 year warranty. As far as I know Exped will provide warranty replacements but I wasn't bothered raising a stink about this one out of warranty. Some people have had these mats last a good long time and there have been many failures so I was hoping to gain some insight into the cause of the failures and if there is anything that can be done to prevent them. I couldn't really determine why the baffle ripped, there wasn't any visual deterioration in the materials that caused it to rip, everything still looked good inside, except for the torn baffle obviously. I'm left with the impression that the baffle material is just a weak point and variation in production can make some mats more prone to having the baffles blow out. If you have a good one and use it carefully it'll probably last a good long time.



Thanks for both the clarification (2 year warranty) and the speedy reply.

Though my Synmat hasn't failed, I've lost faith in it from all the online complaints I've read.

Next outing I'll be trialling my new Sea to Summit Ultralight Insulated
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Re: Investigating an Exped mat failure

Postby undercling-mike » Fri 01 Jun, 2018 12:17 am

Nuts wrote:I'd agree with that venture tape being a good choice, wouldn't the baffle tear/repair be forced on the joint in shear? (or maybe it broke too close to the join already?)


Yeah, the baffle tore off right at the join.

Also very interesting to see the different baffle material in your synmat! With that heavier woven material for the baffle it could well be that the failure is the baffle delaminating rather than tearing. I seem to remember some claims about the mats being hydrolysis resistant when the synmat Hyperlite and Winterlite came out (my mat) and it gave me the impression at the time that they had worked to improve the baffle joins after previous failures. Hmmm


I hope the new StS mat works out for you Aidan, can't remember seeing any failure reports with those ones (not that I've looked). Maybe you can use the synmat for car camping or as a loaner on overnight trips where the consequences of failure aren't too great.
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