Gossamer Gear 1/8″ thinlight pad – R value and weight?

[Yoyo]

I have a 1/8" GG thinlight lying around that I purchased in 2013-14. I'm going to try to use it to supplement my Exped Synmat UL7 to add warmth. I was wondering how much R value it will add? Also, for some reason my pad (after removing 3" or so off the end) weighs in around 3.5 oz–a little on the heavy side for such a thin pad. GG lists it at 2.4 – 2.8 oz.

http://gossamergear.com/thinlight-insulation-pads.html

My old GG 1/8" thinlight from around c. 2008-09 weighed around 2 oz or less. The material feels a bit different from the older one, too. Does the heavier pad mean it has a higher R-value? Did they change materials?

[James Marco]

Well, R values for 1/8" foam is about .3 or .4 or so.

Yes, they did indeed change the materials or supplier. The old corrugated 70-72"" NightLights I got in 2006, 2007, 2008 were about 9oz-10oz. The new ones are about 4.5-5oz for about 29". Or about 12-13oz for a full 72" length. Nunatak carries full length pads whereas GG only carries shorts. About the same weight. I believe GG dropped them because they were loosing money shipping them. (Glen Van Peski mentioned this a couple years ago on this list.)

[Bob Moulder]

Does the heavier pad mean it has a higher R-value? Did they change materials?

Probably, and likely. :^)

I tested some of the recent vintage (I assume) 1/8" GG stuff this winter when trying out different air mat + pad configurations and it definitely helped but was not as good as 1/4" of the same material (which I got from Kline), which in turn was not as good as a TR Solite.

[James Marco]

"Does the heavier pad mean it has a higher R-value?"
I don't really know about that. I would guess that higher density means greater heat loss and lower R values. But, because it is so thin I really doubt that it changes significantly. The difference between .4 and .5 is about 1:50 or 2% based on a winter minimum recommended R5 value for ~15F. Of coarse, this varies from person to person.

Philip W. did a good overview of R values and many common pads along with updates, here:
http://sectionhiker.com/sleeping-pad-r-values/

[Yoyo]

Can someone weigh their thinlight pads 1/8" and report back?

Also, is there another source for a lighter pad other than GG?

Read Sticksblog from a few years back, the 1/8" pad from GG used to weigh around 1.7 oz. The fact that the pad has doubled in weight has me wondering if the material is completely different.

[Bob Moulder]

I just measured a piece (1/8 inch) that is exactly 19.5 x 59 inches. It weighs 2.68oz (76.0g)

I don't have any sort of durometer, but it doesn't seem super dense. This winter I used it down to about +10F with various air mats and it didn't seem to offer quite enough additional insulation to make it worth the effort. The 1/4 inch was a definite improvement, and the TR Ridgerest Solite was excellent, very warm down to 0F with just about any air mat. But then it's 14 oz, so it should be.

[Chad “Stick” Poindexter]

I was going to say mine weighed 1.7 oz, but you beat me to it… Anyway, it seems most folks I have talked to in the past has reported weights between 2 & 2.5 oz for their 1/8" Thinlight pads, but this has been some time back… not sure what they are at the moment. As for how much Rvalue, I can't say, but it has saved my butt (literally) a couple of times by layering it on top of my air pads… I know that doesn't help much… sorry.

[Yoyo]

Chad,

You mention you used it on TOP of your air pad, but I was planning to use it underneath (to prevent punctures as well). I'm switching over to the Synmat UL7 from my Xtherm b/c it's more comfortable, but the 20D fabric has me concerned.

Is there an advantage to placing the thinlight on TOP instead of UNDERNEATH?

[Link .]

HERE is Rogers explanation for having the thinlight on top

[Dylan Atkinson]

My 2013 (ish) 1/8" pad at 19.5" by 59" weighs in at 2.85oz.

[Chad “Stick” Poindexter]

David, IME, I found that I am warmer if the ccf pad is on top of an air pad.

Saying that, I carry the 1/8" pad in the colder months, and use it where I need it depending on the situation. If it's not that cold,I will put it under my air pad to help protect it, but if it's cold, I switch it to the top to stay warmer.

You may think that no matter where they pads are placed, it would be the same, but I have personally found this not to be true…

I have also acquired a SynMat UL7 (Christmas present), and will be taking it again on a hike next week, and again, I will be carrying the 1/8" pad… I think it won't be so cold that I would need it on top, so it will likely end up under the air pad. But, I'll see…

[Bob Moulder]

I tested both ways in very cold weather and TOP is waaaaayyyy better, at least for me.

[John Klinepeter]

My Gossamer Gear Pad, guessing 10+ years old, 19 X 56 X 1/8 inch, weighs 2.1 oz.

FWIW, my Suluk46 (I believe my memory is correct on the source; pad no longer available) pad, perhaps 6-7 years old, is 46.5 X 72.5 X 1/8 inch, weighs 4.1 oz.

[Mike M]

definitely a new material- my new GG 1/8" pad is 3.1 oz, one my old ones are 2.2 oz; the old one is a very light grey, new one dark grey

the new one is tougher, the old ones tore pretty easy

as far as R value, probably not a ton of difference; the rule of thumb for ccf pads I always heard was 0.75 for every 1/8"

[James Marco]

"as far as R value, probably not a ton of difference; the rule of thumb for ccf pads I always heard was 0.75 for every 1/8" "

Well, I don't know but i believe this is rather high. 8 layers of 1/8" would have a thickness of one inch and an R6. At that rate, 8×3.1 would be 24.8oz or around 25oz. Slightly heavier (by 3 or so ounces) but with more Rvalue than an Exped Downmat7.

One thing is that with inflatables (like NeoAir X therms, etc.) they will bleed heat from edges. You are generally warmer placing the 1/8" pad above them.

[Anonymous]

An alternative if another ounce is Oware 3/16 inch pad the 19 by 40 pad is 2.75 ounces, the long is 76 inches by 20 inches weighs 5.25 ounces. A 60 inch section similar in size to the GG thin lite 1/8s will weigh right at 4 ounces. A little thicker. I have the 40 inch plus their 50 inch long .5 inch thick CCF pad. Am also influenced by the fact FREE shipping for Oware, and my experience of somewhat expensive shipping costs for GG.

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