What happens if you?

“What happens if you take 2 40 deg sleeping bags and put them togeather?Does it then become a 20 deg bag?”

“No, I'm pretty sure that would be an 80 degree bag. ;-)”

“Actually, I really doubt it becomes a 20 degree bag. Might be more, might be less, but I don't think it is a mathematical question.”

“A 80 degree bag?

Actually, I read somewhere that said it wasn't a very good idea, because the outer bag would compress the loft of the inner bag...don't know if it's true.

For sure you'll be carrying more weight though.”

“I think it depends on how you "put them together". If you stuff on inside the other, you will get a tight fit.

If you zip them together and share the "double wide" bag with your wife or girlfriend,,,,,,,,well you get the point.”

“The 80-degree answer was a joke.

I said it wasn't mathematical because of exactly what you said. The insulative properties of the individual bags would be adversely affected by combining them. But there would be an additional insulative effect from the airspace trapped between the two bags. So I don't see how you could answer the question.”

“It works if one is larger than the other and doesn't compress it. I have summer bags in a large size so that Sauron and I can use them in the winter as overbags if needed. They are 50 degree bags and they usually extend a bag by about 10 degrees. For example, if I put a 0 degree bag in it it's now good down to -10. I like this because in the summer when it's that warm it's nice to have a big roomy bag and I love the idea of something doing double duty.”

“I just wanted to try something diffrent becuase I have 2 40 deg bags and a 0 deg bag and the temps have not been cold enough for the zero and I am getting tried of taking the zero bag so I thought I could put my 2 40 deg bags togeather and try that.By I guess it won't work.As soon as I have some xtra money I am going to get a 20 deg bag.

Thanx's everyone for the info...:)”

“Thank you Skullcap you just answered my question.

You Rock......:)”

“Not quite, Violin. There is an error in your formula, but I will leave it as an exercise for you to find it.”

“Someone (Slumberjack, Kelty?) was selling a two bag combo that resulted in three different temperature range bags. The drawback was that the cold weather set-up (both bags, nested) weighed about 50 lbs and required a seperate pack to carry it.”

“Good God Violin, you're giving me graduate school flashbacks. Bama's Engineering school thought it would be lots of fun if we had to take 2 graduate level math classes along with our engineering stuff. I had just about blocked out that painful memory, but now IT'S BAAACK! PDE's are lots of help when designing the structure for a building. I think the last school I designed required all 4 branches of math: addition, subtraction, multiplication, AND division.”

“It's Slumberjack and the bag combo is in Campmor's catalogue. I have used the bag in a bag thing and it worked pretty much as Skullcap described - better than I anticipated. Happy trails.”

“There it is.

OK maybe I exaggerated a little: 6lb, 4 oz & 11" x 18" rolled.”

“Wiggy sells at over bag system too and there are others too. An yes the result is three different temperature rating arrangements. See Wiggys.com”

“The squaw on the hippopotamus is equal to the sum of the squaws on the other two hides.

Remember?”

“LOL Tilt! I had a thermodynamics professor I couldn't understand until 6 weeks into the class!”

“I know what you mean smiley. I had a mechanics of materials class where no one understood the guy at first. He underlined the last 3 letters of his name and pointed at himself. This meant for us to call him by those 3 letters. At the end of the semester we could tell each other jokes, albeit engineering humor.”

“LOL @ Fritz!!!!!!!!!”

“One way to find out:
Go outside at night when it's cold as all get out, lay down in said bags, and see what happens.
You can then post a nifty graph like the gear geeks do on boiling points using different stoves/fuels/pots---fun for hours.”

“Ya I could do that.”

“"...But there would be an additional insulative effect from the airspace trapped between the two bags. ,,,
Fritz
02:32:44 PM
02/20/02

True. At times in cold weather, I have unzippered a second bag and spread it like a blanket over my sleeping bag. A blanket would probably work just as well. The cover inhibits most of the air circulation around my sleeping bag. In other words, the air warmed by my bag cannot rise in an unrestricted manner and be replaced by cooler air. Heat transfer is minimized and I can sleep warm as toast.”

“If the Nazis were still around we could do some experimenting to determine the effective temperature range of the two bags.”

“The Nazis are still around. It's the third biggest political party in Germany. But I fail to see what this has to do with testing sleeping bags.

Are you trying to be funny AGAIN Bacpac?”

“Ya I guess we could.”

“rosey, maybe you could post this question on the brown shirts newsgroup.”

“Or maybe you could just tell me, wiseguy!”

“Haha!”

“I say put the two bags together and try it. If it doesn't work (but I think it will) you can stimulate the economy and buy the 20 degree bag. If it works you can pat yourself on the back ammused by your own cheapness, and then go buy the new bag anyway.”

“All right I will and if it don't I know a 20 deg bag I want.”

“I'm not sure how the bags are rated, but my 20 degree bag is good down to about 40 degrees. It's a Campmor goose down, mummy bag.”

“I thought about getting one of the 20 deg campmor sleeping bags.They are cheap and they last a long time.”