Exped downmat vs. Stephenson’s DAM

[Diplomatic Mike]

The site is a mess Hendrik. Have a look here.

[Hendrik Morkel]

Thank you, Mike. So prices starting at 140$ + shipping to Finland. I reckon I might get cheaper away with an Exped 7 or 9. The Exped 7 has heaps of good reviews here, the Stephenson's DAM none. Hmmm.

[Ethan A.]

I can't speak for it myself as I haven't tried it yet, but there are many positive comments about the Stephenson in the forums and I've gotten several PMs from very happy owners.

[Jolly Green Giant]

I had, and returned, a Stephenson's DAM. It's a top notch and extremely warm product if you can muttle through the odd marketing and dysfunctional website. Their customer service is also excellent as is their entire line of products. Unfortunately, the weight on it was significantly higher than expected and despite thinking it was a quality item, I knew it would never make it into my pack. Mine was the largest size. I've found that I have no desire to have anything other than full body length when dealing with something over 1" in loft/height as the drop-off is otherwise too uncomfortable to my back. The list weight was 24 ounces. With the sack (unmentioned in the ad for it), the total came to over 31 ounces. Instead, I either double up on CCF pads or use a Thermarest Prolite with a CCF pad.

[Ethan A.]

Because of the weight? Yours was one of the larger sizes if I recall, right?

What do you use now?

Strange marketing I don't care about. It took one email to the company to clarify ordering and they responded right away. I do care about customer service and integrity.

[Lynn Tramper]

Our DAM 60s were spot-on advertised weight. They are a well made (though really cheap looking) mat, but I don't find them as warm as I expected at colder temps. It feels like it's just too large an area to heat up, and unlike closed cell foam, it isn't instantly warm when you lie on it. The down is also almost never evenly distributed, and it's not easy to re-distribute it if you see an area that needs more down. I imagine the Exped mats would be the same though.

If anyone is seriously considering trying a Stephenson's 60 inch mat, send me a PM. I'm sure I could do you a pretty good deal on one or two ;)

[obx hiker]

The dam air mattress was designed by Jack Stephenson to fit into a sleeve in the bottom section of the bag. The bottom section is the heaviest individual part of the 6 possible parts…did I get that right? 1. thin top layer, 2. thicker or middle layer, 4. bottom layer 5. dam air mattress and 6. mosquito net top.

Stephenson was an aerospace engineer. The guy was talking about vapor barriers and insensible moisture transpiration by 1970. Anyway.

The bottom portion of the multiple layer bag has down baffles that fir around all 4 outer edges of the dam air mattress. I'm sure this improves the already impressive thermal efficiency of the dam by a factor. These bags are really well designed and (were) made of the finest available materials with the finest available down.

I did have a DAM mattress fail but not because of a leak, or not a puncture anyway. Bacteris of some sort had broken down or decomposed the coating on the inside of the fabric of the mattress to the point that it would leak air very gradually overnight with the weight of a person on it.
The bag was made in 1986,I didn't always keep it in an air conditioned house and the humidity and moisture levels around here coupled with the heat are very high. I imagine that was a problem with the urethane then in use? coupled with our hot and humid climate and shouldn't be be a problem now. Besides the mattress was 20 years old and they repaired it to boot.

I have always found the Stephenson family to be easy to deal with and stand behind their products; but I have not yet had dealings with William Stephenson or the company since the elder Stephensons turned the business over to him.

My first visit was in 1974 to their home on Hatteras Court in Woodland Hills Ca. ( I live on the NC Outer Banks near Cape Hatteras, hence the OBX; and grew up in the small town of Woodland NC which is why I can remember that CA address. It was actually 100 degrees the day I stopped by their shop on Lake Winnepasauke in NH @ 1998! and no one was naked on either visit! I also own the old frame pack with the hip "arms" on the frame. You should see the looks I get when I break it out on occasion!

I guess modern technology and the desire to go even lighter is catching up to the Stephenson line of products but the bags are really warm, very comfortable and I wouldn't think of reaching for another bag any time weight isn't a critical issue or any time you want to be safely warm way below zero. As you can see from the interest in this thread at 19oz the dam matress is still competitive on a warmth/weight ratio.

[Ethan A.]

Hi Cola, very helpful info. Thanks for sharing.

[Abbey Bean]

I know this is an old thread. I tried to PM Lynn Tramper but there was no address to PM to. So, if anyone happens to see this and has a 60 DAM for sale, I can be reached at I have a @hotmail acccount. The address is aaachinesemedicine.

[BlackHatGuy]

Brian Latta is selling two Stephenson DAMs here, but they're 70s, not 60s. Great price though if they're still available.

[Ethan A.]

Lynn sold her DAM 60s already in any case (she had PMed me about them at the time).

[BlackHatGuy]

nm

[Abbey Bean]

Thanks Doug,

FWIW, my understanding of the Stephenson DAM sizing is this. The DAM size is referenced by the sleeping bag it fits into. The 60" DAM fits the 60 inch girth Stephenson bag. That size DAM is 70 inches long.

Also, FWIW, I have the same problem with my original DAM as someone posted here (sorry don't remember who). It leaks air very slowly. When I inflated it and put it under water there were many tiny slow bubbles coming from all over the mattress. When I held it up to the light, there were patches of discoloration on the inside.

I will contact Stephenson about it, but I don't have time to mess with it right now. I have had good experiences with customer service over the phone with them. After reading other's experiences, I would be hesitant to email.

I love the sleeping bag and the DAM, even with the problem I had (which was probably due to spending a very rainy year in a basement apartment – live and learn – I stored it up high in a closet with a dehumidifier, but obviously it wasn't enough). I've put in a lot of nights on it – use it when its cold and swap out to something lighter in the summer.

Thanks to all for all the good info on this forum. I have learned a lot.

[obx hiker]

Hi Abbey,

C'est moi with the leaky pad. The coating ( urethane??) degenerated or was attacked by mold or something which caused to slow leaks. Went to sleep everything was fine. Woke up with a partially deflated pad. Makes sense you could see it but I didn't think of that at the time. I tried wetting mine to see the bubbles but you actually had to apply pressure in the form of a body to get it to slowly leak.

Stephenson repaired it by "painting" it with urethane which in my opinion redered it just about useless for back-packing as it now weighs 33 ounces and it's a lot more stiff but it doesn't leak! I think they would have re-shelled using the original down but that was expensive and they'd have passed on the costs to me and without my knowledge they just picked the least expensive route. It was pretty old anyway.

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