Freezing Temps and Open Cell Foam

[CITC]

Testing the ocf bag in a modern day freezer will not be true to life results. Frost and moisture are controlled in todays techno freezers. (When is the last time you had to defrost your freezer?) And most freeze only to 20* min. Sure, there are some super chilled freezers out there, but still with moisture management already in the chilling process. The coldest I've worked on is a -40 flash freezer at an ice cream making co., very cold. Try taking a 80* screwdriver into a -40* environment, p.s. cell phones don't like it, either.

True frozen outdoor sub-freezing temps must be used to insure "real-life" results.

Gargoyle,

Thanks for that information. You have an excellent point.

What happens to the moisture thats left in the ocf when I get out in the morning? There has to be small percentage of moisture still migrating towards the surface, which is now beginning to freeze as I pack up camp and move to the next location, correct. So, night #2, my ocf bag is slightly frozen slab? Night#3, night #4???

Sure, I can shake out my moisture mngmt. sheet. (neat idea, by the way) But what about the pad/pads that are still laden with moisture, even at a small percentage. I'm speculating that the moisture would continue to build over time and the daily freezing cycle would render the pads useless.

I've done limited cold weather camping, but I have learned frost build up is inevitable, be it in a tent, camper, wherever. I have not tried the hammock in the winter..yet.

I think your product is cool and a good idea. More testing in real life situations will be needed. One night test at home doesn't cut it. Give it a week in normal cold conditions, slush, snow, wind, etc. without the opportunity to thaw, and then I'll be impressed.

Do have a photo of your bag rolled-up? Just curious about pack size? I know it weighs 9 lbs. I'm thinking if you could lighten it up and make it work with the hammock, you'd have a good set up.

Without an opportunity to thaw and allow moisture to escape, (i.e., packed away in a backpack), where does this moisture go? It freezes inside the ocf?

These guys figured out cold camping, a long time ago.

Yes, lost amongst the mind numbing discussion on partial pressures, relative humidity and iced substrates, this was the question that I was really trying to have answered. Thanks gargoyle for bringing it back to reality.

Even if the system could be whittled down to 6-7 pounds, you'd at least be getting much closer to a deep winter camping setup of traditional bags plus pads. It would be fun to try in any case.

You raise a very good question, "What happens to the moisture that is migrating out when you get out of the bag?"

I apologize if I've given you the impression that I have only spent one night at a time in this system. This is surely not the case. The -4F temperature that I experienced occurred only one night in the week that I was outside. The other nights of that stay fluctuated somewhere above that, but not above 32F. My biggest concern for that week was daytime temperatures that would be above 32F and would offer, to some degree, thawing to take place. This is not what I wanted.

Now, concerning the moisture left in the bag/pad. Yes, there is some, but when you get back into that bag the next night, your body heat will thaw that moisture out, and it will continue to carry on through to escape.

The foam insulation reaches a point of equilibrium, so under those conditions there will always be a small amount of moisture left in the bag.

Jim, my mentor with 30+ years of experience with this system (much of it in the Arctic), told me that one fiber bag outlasted all the others by a few days. When he was done with that particular stay in the Arctic, he placed this fiber bag, and his foam bag (he spent equal time in both) in large plastic garbage bags when he went home. He weighed both of them, then allowed them to dry out, and weighed them again. This gave him the weight of the water that both systems had retained during that time in the Arctic.

The fiber bag had retained 8lbs of water, and the foam bag 8oz. That's quite a significant difference. He speculates that had he spent another night or 2 in the fiber bag it would have failed.

The picture of the bag that I posted is the one that I use now. I'll stuff it and take a photo and post it here.

While I agree that the Inuit people have had Winter living figured out for generations, do you have a caribou outfit, and knowledge of their techniques? I don't.

[Cannibal]

While I agree that the Inuit people have had Winter living figured out for generations, do you have a caribou outfit, and knowledge of their techniques? I don't.

Funny enough, one of the down quilt vendors here probably does. I know he was talking about brain tanning a while back.

[Pitch]

What happens to the moisture that is migrating out when you get out of the bag

This will freeze, but I believe that due to the hydrophobic nature of the material in question, the amount of moisture actually left in the bag should me minimal. If the material were more hydroscopic this would be another story

[CITC]

If I may, I'm going to expand your question to make it more relevant.

Lets try:

"For a given temperature range, what weight would you consider for a backpacking bag?"

and then

"Please give several temperature ranges and associated weights"

and a follow up statement of

"No worries about exact temps or weights... this is completely subjective but interesting nonetheless

Everyone who has experience w/ this should chime in

Thanks for bringing the question into a more relevant state.

In a previous post I stated my experience that these materials allow for a very broad comfort range. My own personal experience has taken me from 72F to 20F with no additional changes to the way I dressed (sweats, socks, cap). That's 52 degrees; a far broader range than any other bags I own. This is why I use this bag exclusively year round. The others are collecting dust...

[TeeDee]

This will freeze, but I believe that due to the hydrophobic nature of the material in question, the amount of moisture actually left in the bag should me minimal. If the material were more hydroscopic this would be another story

That is the problem with down - it is hygroscopic. Even with the natural oils, it attracts water. Once vapor gets into the down it is very difficult to get it out. We have a LOT of geese around here and they stay year round. Watch them sometime - they spend a lot of time grooming their down and rubbing in more oil.

So a minimal amount is left in the foam. The next night that minimal amount is thawed by the body heat and continues on out of the foam.

In down, even if the water is thawed by the body heat, it stays in the down and more accumulates.

I'm not dissing down for what it works for it is very, very good. It is just not good for all conditions.