Synmat leakage

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ScotRoutes
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Synmat leakage

Post by ScotRoutes » Thu Jun 13, 2019 9:59 pm

I have a Exped Synmat HL7. It's slowly deflating. I've tried to find the leak by partially inflating the mat and holding (parts of) it under water. This is comedic enough. However, nothing is showing up. So......

(a) any hints for finding the leak?
(b) should I just put in some Stans sealant and squish it around?
(c) if I was to replace it with a Neoair (Xlite I guess), would the Exped inflator bag work or am I also needing a new inflator?
(d) other than Klymit are there other mats I should be considering (Sea to Summit maybe?)

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whitestone
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Re: Synmat leakage

Post by whitestone » Thu Jun 13, 2019 10:04 pm

Colin, I've found that the one-way flap in the valve sometimes doesn't seal right and it leaks air. If it's really bad the mat won't even inflate :roll: I'm assuming this isn't the usual softness due to the air inside cooling on contact with the ground?

I doubt one company's inflator bag will work with another company's mat. Could be wrong on that.
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ScotRoutes
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Re: Synmat leakage

Post by ScotRoutes » Thu Jun 13, 2019 10:13 pm

whitestone wrote:
Thu Jun 13, 2019 10:04 pm
Colin, I've found that the one-way flap in the valve sometimes doesn't seal right and it leaks air. If it's really bad the mat won't even inflate :roll: I'm assuming this isn't the usual softness due to the air inside cooling on contact with the ground?

I doubt one company's inflator bag will work with another company's mat. Could be wrong on that.
I thought it might just be the "cold ground" issue when I was out last weekend but it's definitely not that as it's not even retaining air in the house. I also checked out the valve flap and it's OK. Bloody annoying. I hate just buying something new when the solution is to repair instead but this has me stumped.

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Re: Synmat leakage

Post by Pirahna » Thu Jun 13, 2019 10:33 pm

I had a similar problem, the way I found the leak following advice on here was firstly to get some good quality washing up liquid. Mix some the washing up liquid with water in a jar so it's thick and soapy. Take the mat to the bathroom and using the shower head in the bath wet the mat, then paint on the liquid, it will bubble where the leak is. It took a while but it worked. I tried it first with some Eco liquid we had in the cupboard which didn't work, I think I used Fairy. I fixed it as per the Exped instructions, three applications of glue over the hole, I didn't use a patch. It's been good ever since.

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Re: Synmat leakage

Post by BreninBeener » Fri Jun 14, 2019 12:33 am

What is the glue used to repair these mats?

I still have the patches, but have lost the glue...doh

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Bearbonesnorm
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Re: Synmat leakage

Post by Bearbonesnorm » Fri Jun 14, 2019 7:11 am

After inflating, try wetting the 'valve cap' a little before fitting, then once in place twist it a few degrees.

Works on mine.
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Re: Synmat leakage

Post by HUX » Fri Jun 14, 2019 7:36 am

I had exactly this problem Colin and spent ages looking for leaks. Try inflating the mat as normal, bit of spit on the bung, stick the bung in then twist it a fraction. Works for me. I think Stu had the same problem.
^^ beat me to it!

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Re: Synmat leakage

Post by Scud » Fri Jun 14, 2019 8:38 am

I found that over time where i had folded it, the creases had "thinned" the material, so there wasn't a puncture as such, air was leaking in small amounts along most of the crease line.

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Re: Synmat leakage

Post by Bearbonesnorm » Fri Jun 14, 2019 9:09 am

found that over time where i had folded it,
Roll it.
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Re: Synmat leakage

Post by ScotRoutes » Fri Jun 14, 2019 9:12 am

I fold and roll, so the mat ends up 1/3rd width. I'm guessing it's those longitudinal folds that can be the issue, especially as they are then subject to abrasion in your pack.

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Re: Synmat leakage

Post by pistonbroke » Fri Jun 14, 2019 9:20 am

I've got a Downmat UL7 and therefore don't need insulation on my back so use a quilt. I roll the quilt bivvy and mat together which probably cushions the folds. I've found the same issue with leakage around the valve so comforting to know I'm not alone.

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Re: Synmat leakage

Post by Bearbonesnorm » Fri Jun 14, 2019 9:26 am

Well, I roll my mat without folding it, then form it into a kind of circular doughnut and then put it inside my drybag ... no folds.
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metalheart
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Re: Synmat leakage

Post by metalheart » Fri Jun 14, 2019 9:37 am

Not exactly much help, but I've found Exped warranty has been decent (a simlar mat to yours, baffles burst, and the pump bag rip you saw me do on the recent MM200-ish thang).

Both were replaced without issue.
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Re: Synmat leakage

Post by whitestone » Fri Jun 14, 2019 9:48 am

How many nights usage has the mat had? Mine is somewhere just over 50 and I "fold and roll" in the same way you do. Might need to ensure the folds aren't always in the same place.
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Borderer
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Re: Synmat leakage

Post by Borderer » Fri Jun 14, 2019 10:16 am

I find leaks by blowing the mat up to fairly high pressure, then systematically running it along a few millimetres from my cheek. I can feel the draft from the leak that way that I can't find by running a (less sensitive) hand over it.

Also sometimes you can hear the leak if you pump the mat up fully and are in a really quiet space.

Sorry if this is a bit simplistic - it has just worked for us when we have had to deal with a leak in the middle of a trip.

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Re: Synmat leakage

Post by Chew » Fri Jun 14, 2019 10:50 am

The warranty was good when one of my baffles broke.
Set it back and got a replacement without fuss.

They usually go a bit soft after initial inflation, but if it’s going down completely I’d see if you can send it back.
Think it was a 2 year warranty
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Re: Synmat leakage

Post by ScotRoutes » Fri Jun 14, 2019 11:31 am

Borderer wrote:
Fri Jun 14, 2019 10:16 am
I find leaks by blowing the mat up to fairly high pressure, then systematically running it along a few millimetres from my cheek. I can feel the draft from the leak that way that I can't find by running a (less sensitive) hand over it.
Yep. Tried that method too, it's how I find holes in inner tubes. Good to know I'm not the only one to be seen at the track/roadside looking daft.

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Re: Synmat leakage

Post by ScotRoutes » Sat Jun 29, 2019 5:04 pm

Saved by Fairy Liquid (maybe)

I made up a soapy solution in a garden sprayer and covered both sides. I eventually spotted a little area where it was foaming (not quite bubbling). Dried it off and I've now applied the three layers of glue. I'll inflate it later to see if that's it fixed.

If it's OK, then I'll have a replacement, unused, Synmat HL to return or resell.

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BigdummySteve
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Re: Synmat leakage

Post by BigdummySteve » Sat Jun 29, 2019 10:19 pm

ScotRoutes wrote:
Fri Jun 14, 2019 11:31 am
Borderer wrote:
Fri Jun 14, 2019 10:16 am
I find leaks by blowing the mat up to fairly high pressure, then systematically running it along a few millimetres from my cheek. I can feel the draft from the leak that way that I can't find by running a (less sensitive) hand over it.
Yep. Tried that method too, it's how I find holes in inner tubes. Good to know I'm not the only one to be seen at the track/roadside looking daft.
Definitely not the only one, my method is to lick my lips then run the tube around close to my mouth.
Must look very odd :-bd
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Re: Synmat leakage

Post by Jurassic » Sat Jun 29, 2019 11:21 pm

In case the leak you think you found isn't the problem, my Synmat goes down randomly every so often and I've put it down to the bung/plug thing not sealing correctly (maybe due to tiny bits of grit or similar being on the plug or socket mating surface?) Most the time the mat's fine but every now and again it goes down until I clean the plug. Sounds similar to Hux and Stu's issue.

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Re: Synmat leakage

Post by benp1 » Sun Jun 30, 2019 9:16 am

I had a slow leak from my thermarest, couldn't find it. Sent it back, they found a defect and replaced it

Warranty is excellent!

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