Moisture management in self-inflating mattresses

Lightweight, convenient, and moisture-free.

http://www.themillair.com/

EDIT: Just realized you said *self inflating* mattresses. So…why are you blowing in them?

Self-inflating or pump inflated mats will accumulate moisture if you are in any sort of humidity and subject to dew point temperature drops. Pumps will lessen the problem, but not eliminate it.

In one 5 night Grand Canyon trip this past February, filling my Exped UL7 with a pump, I condensed enough moisture to watch it puddle on the inside when held vertically.

I spent a day "cooking" the mat in a tall window, deflating, inflating, "cooking" again, etc. until I could no longer see water running around.

I've read a lot of different methods for drying out inflatable pads, but, because the majority of them are urethane-coated nylon, I don't think leaving them out in the sun is a good idea. Nylon 6,6 loses 50% of its tensile strength after 100 hours in sunlight, and urethanes are even more sensitive than nylon. There are accounts of the urethane coating on tent fabrics being destroyed after a few full days in direct sunlight.

I suggest keeping the direct sun off the fabric, but storing the mat with the valve open and downwards is a good idea. Works for us, anyhow.

Cheers

how is that moisture free?

+1 for keeping it unrolled with the valves open.

Also you could you a hair dryer on the low setting.

Regarding my Exped UL7 "cook and refill" – each "cook" session lasts about an hour. Temps never get close to "hot", just mildly warm, although if forgotten it could happen. And inflation is on the low side to allow for the expansion of the warmed interior air.

I tried the low temp hair dryer trick, but the valve is stiff enough to defeat it. Hooking up a "drying snozzle" would be the ideal way to go.

Open and on the floor works well for self-inflators, but gets you nothing for something like a UL7, which doesn't have any internal support.

You store it with the valve open so the foam doesn't get compressed, makes it self-inflate better when you use it

I don't think there'de be enough air circulation to dry it out

While it's stored, you could occasionally squish the air out of it and let it reinflate

If you put it in the sun, it may tend to delaminate the foam from the skin which is a problem with self inflating mattresses.

You could weigh it when it's dry, and then weigh it after using it to see if it has any significant amount of water

Hopefully you don't blow into your self-inflating pad? With the two I had some years ago, I always had to let a little air out when it was fully inflated; I never had to blow into it.

My recent experience is with insulated air pads that do need to be blown up (non-self-inflating). I've been using a trash bag with one corner cut out, plus a rubber band, to inflate my Kooka Bay pad. However, I did blow into my previous insulated air pad (POE Insulmat Max Thermo) a lot. What I do a couple of times during backpacking seasons and definitely before winter storage is to set up an electric heater, hold the trash bag in front of the heater to fill it with air and inflate the pad with the warm air in the trash bag. I close the valve and let the pad sit for about 5 minutes, then squeeze all the air out and try again. 3 or 4 iterations seem to do the job, or at least lightens the pad a little. I then store the pad flat on the floor under a spare bed (not recommended if you have a cat!), with valve closed and a small amount of air inside (the insulation seems to stay fluffier that way, although since I can't see inside this may be my imagination). Remember, this is for an air pad that does NOT self-inflate!

With the self-inflating pad, just having the valve end in front of the heater and letting the pad inflate with the warm dry air, or pointing a hair dryer (on low, not hot) right next to the valve while the pad inflates, then inflating and rolling up the pad several times would do the job. For a self-inflator, it's suggested to store it inflated with the valve open.

For the reasons cited in the posts above, I'd keep the pad out of the sun. If it's a hot, dry day, you could inflate and deflate in the shade, but not on grass, which is always a bit damp.

…that I can still get a good night's sleep on closed-cell foam!

But I got one of the new REI Stratus pads (like a BA IAC) on mega pro deal this spring, and this discussion has me thinking twice about using it much…

I have more than one of each inflatable (non-insulated) and self-inflating pads, both have been horribly mistreated: blown up with my mouth, stored rolled, left in the sun for days. I slept on one of the therm-a-rests for 6 weeks straight more or less outside in the Army during the TN winter, rolling it up nearly every morning. Then took it to Afghanistan.
The inflatable one has been a float toy at the lake, and been motorcycle camping a dozen times.

Both still work fine. If they are mold-ridden, they show no loss of structural integrity.
In fact, the above mentioned one is inflated on my 10 month-old son's floor where I have been sleeping while he's sick.

I agree that down is probably more sensitive to mold than foam, but I doubt it's a big an an issue as some believe.

I agree with Jerry, moisture can accumulate over time and increase the weight of the mattress.

In another similar thread, I recommended using something like the Instaflator, but waiting for a little while before pushing the air into the pad. This allows the moisture in your breath to cool to the cooler air temperature and for some of it to condense before going into the pad. That air should warm up while you sleep on it, and absorb moisture. Quickly expelling the air from the pad while it's still warm should dry it out.

I've had Therm-a-rests since 1993 and have always filled them with lung power. I store them on end, unrolled, horizontally with the valve open. I have yet to smell any nasty air coming out of them, but always wondered. I now have an EXPED downmat, neoair and prolite. The prolite I store, valve open, flat. The downmat and neoair are stored hanging on a wall – valves down and open. If I get a pump bag, I'll probably inflate with some hot, dry air a couple of times and call it good. Downmats should always be stored unrolled to keep the down in a lofted state.

When the self-inflating Thermarests first came out, they actually did inflate by themselves many times; however, a layer of open cell foam had to be added to make them comfortable.

Later, they became more comfy, but it became increasingly necessary to blow them up in order to get adequate inflation. Ditto, for the REI, Aircore, which was more comfy than the Thermarests when new.

Based on the reviews in Roger's article, just ordered a Nemo Zor shorty, on sale at EMS with free shipping. But like my down bag, will keep it unrolled except when packing, and definitely not rolled tight in the back of the wagon when driving across country, often in the hot sun.

Don't know why I never thought of this. Will store it at home as Roger suggests.
Thanks for the thread, Eric.