heating a shelter with hot rocks

Bushman5 said:
one can also pee into a bottle and use that as a heat source :thumbup:.......just dont reach for the lemonade haflway thru the night!!! :eek: :barf:
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It does keep you from having to go outside, but if holding your pee isn't helpful, I would think keeping it against you wouldn't be good either. But maybe me not so smart. :confused:

I have a collection of lexan flasks. Not round bottles, but wrap-around-shaped flasks. Being lexan, they can hold boiling water. Being flasks, they fit nicely inside jackets, or between your thighs. The newest GSI lexan flasks (the only lexan flasks currently available) are my least favorite, but they still work.
 
Quart-sized QUALITY zip lock baggies are handy for in tent urination.

Uh...sounds silly...but practice before the situation arrives. Not funny to have your water splashing in your hovel.

:)



Kis
 
john, good luck with your trip.

i haven't ever played with using hot rocks to heat a shelter, but i have heated some rocks until they were glowing a dull red color before...very hot! they even heated right through tonym's leather glove and gave him a nice blister...and gave the glove a thumbprint...we were boiling water with rocks.

anyways, i would think that if you are using alot of insulation on the ground then burying the rocks wouldn't do much good...you might try warming them up not as hot as you can get them (so they are just pretty warm, not super hot) and wrapping in some spare socks or other cloth, to put by your feet and near your torso, and maybe one against your neck to ease any tension... you could also just try heating up rocks and putting them in the shelter with you, to warm up the air. you would need to seal the doorway though for this.

i found some cool handwarmers a couple of years ago that are reusable. they come in a few different sizes. you click a little button, which releases a spark, which causes the gel inside to crystalize, releasing a pretty good amount of heat for about 45-60 mins (for the size i have). once they are cool and hard, you drop them into boiling water for about 10 minutes to reset them. i accidentally boiled one before it was cool and ruined it...otherwise they are pretty cool. might be something you want to look into...similar to this, but a different brand.
 
I'm trying to wrap my head around this pee or not pee thing.

Okay - drinking a quart of cold water will cause a big energy drop to heat that water up. But the urine is formed at body temperature, being that it is filtered blood.

Given that water has a high heat capacity compared to anything else in your body, having an extra quart of liquid, already at body temperature, actually increases your total heat content. Your bladder is totally enclosed in your body and thus cannot lose heat by convection. If it looses heat, it losses that heat to the surrounding tissues, so there is little net loss. I don't think that you can argue that having a full bladder increases your total volume by enough to actually influence heat loss. One the other hand people are suggesting that you take a heated bottle of water to bed with you. If you thing about it, this is pretty similar to the full bladder problem. In fact, the heated water bottle, after having lost its heat and being external to your body would then start to zap heat away and I would argue it would zap that heat away faster than your bladder water would. I do realize that the big payoff is at the beginning when the bottle is much warmer than the body.

I also certainly agree that it is more comfortable to sleep not having to take a pee. It would also be the death of you if you wet the sleeping bag. I.e. if the cold didn't kill you, your buddy would within a day or two.
 
kgd said:
I'm trying to wrap my head around this pee or not pee thing.

Okay - drinking a quart of cold water will cause a big energy drop to heat that water up. But the urine is formed at body temperature, being that it is filtered blood.

Given that water has a high heat capacity compared to anything else in your body, having an extra quart of liquid, already at body temperature, actually increases your total heat content. Your bladder is totally enclosed in your body and thus cannot lose heat by convection. If it looses heat, it losses that heat to the surrounding tissues, so there is little net loss. I don't think that you can argue that having a full bladder increases your total volume by enough to actually influence heat loss.

I do agree that it is more comfortable sleep not having to take a pee though. It would also be the death of you if you wet the sleeping bag. I.e. if the cold didn't kill you, your buddy would within a day or two.
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Your body has to generate the heat to keep its mass warm. Urine does not generate heat, but will contain it, dissipating into surround tissue, much as any non-heat generating organ/body conduit system does. But it has to be drawing heat to maintain its temperature.

Some heat...no idea how much.

I think.




Kis
 
wow lot of pee talk here...I'm thinking about leaving about a 3x3 work space between my head and the door..I'm debating digging a small pit in there and placing several hot rocks in it to warm the air.. any thoughts...
 
I know this is not quite addressing the original question, and it is way heavy, but if weight is not an issue, an old-fashioned hot-water bottle would do the trick in spades. And, of course, it is easily reused. There are also heat pads that are reworked by placing them in boiling water.

And I don't know all the in-depth arguments, but in canoeing/camping/backpacking over the years, I do know, if you have to pee, get up and pee and get it over with. Laying there, holding it in is not constructive in the least.

Doc
 
I would assume that the rationale about peeing is that if you are uncomfortable you'll be more restless, and that if you move you lose heat faster than if you lie still. If you look at the mathematics alone, both from the standpoint of BTU conservation and in terms of S/V ratios, the win goes to holding in your pee in the short term. But the heat represented by a quart of pee being heated from 33F to 98F is only about 130 BTU. The body's basal metabolic rate is 300 BTU per hour according to Cody Lundin, so the water is really not a big deal. But I would imagine rolling around on the cold ground instead of lying still is a bigger factor, and since your going to have to pee SOMETIME - why go not now and save yourself a bit of possibly increased heat loss and added discomfort too? You will lose those BTU eventually, so the advantages of postponing it seem to be very small - essentially zero at best.
 
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I blame myself for the pissy direction of this thread..... sorry... I just couldn't hold it.


:o
 
Magnussen said:
I blame myself for the pissy direction of this thread..... sorry... I just couldn't hold it.


:o
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That's OK, no need to be yellow here, we all feel the need to just let ourselves go once in a while. Sometimes it means coming across as a prick, other times it means simply shooting from the hip in hopes of others being receptive to our dribble.
 
RescueRiley said:
i've had rocks explode... I've never been tagged luckily.. but they do explod if taken from a stream bed or similar area
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Riley, good topic.
Not just frome stream beds, either. there is a place on top of a mountain in Western MD, where I have camped numerous times, and we ring the fire with large rocks. They are about 1500 feet above any water source, besides rain.
I don't know what type they are, but they do "pop".
never had an extreme "shrapnel" incident with them, but they shatter into 3 to 5 peices.

Heat any rock for this purpose slowly, throwing them right into the hot embers increases the chance of them bursting, just from rapid expansion alone.

If you are really energetic, dig a shallow 5 foot by 2 foot depression where your shelter will be, leave the dirt right next to the depression. Heat the rocks, line them up in the shallow depression, cover with a few inches of dirt and then your bedding material. It's a lot of extra work, but helps with the "cold ground" effect.

Either way, insulated yourself from the ground.

Have fun, be safe!
 
LittleHairyApe said:
I would assume that the rationale about peeing is that if you are uncomfortable you'll be more restless, and that if you move you lose heat faster than if you lie still. If you look at the mathematics alone, both from the standpoint of BTU conservation and in terms of S/V ratios, the win goes to holding in your pee in the short term. But the heat represented by a quart of pee being heated from 33F to 98F is only about 130 BTU. The body's basal metabolic rate is 300 BTU per hour according to Cody Lundin, so the water is really not a big deal. But I would imagine rolling around on the cold ground instead of lying still is a bigger factor, and since your going to have to pee SOMETIME - why go not now and save yourself a bit of possibly increased heat loss and added discomfort too? You will lose those BTU eventually, so the advantages of postponing it seem to be very small - essentially zero at best.
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Yeah this was my thinking. No disrespect meant Magnussen, just wanted to tease out the rationale behind the recommendation.
 
RescueRiley said:
Skunk... It's been a while brother.. NIce to see you posting again.
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Thnaks RR, time got away from me. been busy as can be.
Still around, and I do miss hanging out with you guys.
I'll make it more regular, now that Fall/Winter are upon us, promise.
[groans come from the crowd]
"Oh no, not him again!" :barf:

Have a great time with your outing!
 
kgd said:
Yeah this was my thinking. No disrespect meant Magnussen, just wanted to tease out the rationale behind the recommendation.
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No offence taken ma brutha...... Question everything!!!..... taking someone's word for it will get ya in trouble sometimes.

Thats why I love these kind of forums.... so many different opinions. People aren't afraid to challenge eachother..... and I know I always learn new things and confirm current practices.

:thumbup:
Rick
 
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