Platypus to warm Sleeping Bag?

I though you meant the Mammal. I was going to suggest they are a little heavier than you might want for a bag warmer.

In the winter I take a hard sided nalgene and a soft sided nalgene (wide mouth to not freeze). The warm water bottle in the sleeping bag works great, but make sure the cap is on tight, the bottle is dry, and don't burn yourself.

You want to keep it simple in the winter. Wide mouth, easy to fill old style hard sided nalgene with extra BPA's. Make sure that the threads are clean and dry – no ice. and that you put it in a cozy. We have had some threads ice up and stop the top from sealing…can you say cold wet feet.
I think that a platy would be hard to fill and not hold up.

Enjoy,

Dave

First time I did this I didn't squeeze the air out before I capped it. Put it in my bag while I ate supper. Heard a hissing sound coming from my tent. A pin hole on the seam near the cap and a wet spot in my bag.

For the next 2 nights I made sure all the air was out and I had no pressure or leaks. Even so, after that I switched to Gatorade bottles.

at least 1 nalgene

– easier i find to pour very hot water in
– sock fits over quite well
– less chance of something nasty happening … water in yr bag is a bad thing in general

Thanks guys…

It seems like the general consensus is that the hassle that might come from having to try pouring boiling water into the teeny opening on a platypus(or other normal recycled water bottles) isn't worth the ounce or two saved. Nevermind whether or not the material or seams would be structurally reliable.

Nothing would make a winter night more interesting than a liter of water all over my down bag, so thanks for the pointers to keep a close eye on the rings/sealing part of the bottle. And the sock sleeve is a good idea too!

And Mr. Black… a real platypus would weigh nothing because I could train it to carry small gear for me. It could actually count as negative weight. aren't they poisonous though?…hmmmmm.

edit…typo

James, I'm late to reply but I fill a wide mouth platypus every night straight from a boiling pot of water, into the water bladder, and then into my bag. The bottle will be scorching hot for hours so be careful where you put it up against your body, and the plastic gets very flexible from the heat but will not fail in any way. In the morning when I wake up, the water is still nice and warm to use for drinking. I haven't had a leak yet, but always remove the air when I put the cap on as mentioned above. Been doing this for years with the same container – it's a sure way to keep your feet warm when the temps dip drastically.

We too use a platypus to warm our sleeping bag. I do not have access to a wide mouth platy but find I can pour boiling water into the small opening. I fill the platy 20% with cold on the basis that it may be kinder on the plastic to not be at boiling point. I push the air out. I do think the plastic is a little different and less pliable after this use but I am not sure. We have had no direct failures. Some platy's that have been used like this have failed in normal use, but they might have anyway. We wrap the platy in mitts and use polythene bags to help slip mitt into mitt then in a foam cosy that we made dual use for cooking. It then stays hot/very warm right through the night and does not burn you. If you have an unused dry bag you can put the lot in that, just in case of a leak!
A hot water bottle that weighs nothing, if you had those things with you anyway!

Also try zipping up your mountain parka, cinch the hood up and putting it over the foot of your sleeping bag to both keep tent wall frost of and keep your foot area warmer.

Remember to bring boot liners into your sleeping bag so you don't have frozen toes as you cook breakfast and pack up. It only takes one miserable, toe-hurting morning to make you never forget to do this.

several good points. learned something- thanks -"If you have an unused dry bag you can put the lot in that, just in case of a leak!". I always worried about a leak.