Hot answers tagged

9

Yes, the R-value will add of your different layers. If you wear layer A with R=5 and layer B with R=2.5, the overall insulation value will be R=7.5. To explain this a bit, we think of two layers or flat walls which interact only due to thermal conduction. This is just a model and in reality other effects will come in play. The Fourier Law for thermal ...


9

I have a self-inflating mat, and I think the foam serves three purposes. In order of importance: It sets the shape of the mat when inflated. Think of the foam as limiting how far the opposite walls of the mat can be in any one place. If you didn't have this, the mat would become more of a circular tube as it is inflated. For cushioning, the foam does ...


8

Depends on the situation and therefore the gear you have along and the environment you are in. For example if you are on an alpine tour, you can do similar as we did this year in a bivouac: try to get in wind protected area (not so important in your case but even with a tent it changes your comfort) get a flat surface (heads up) lay your ropes directly ...


8

I think the reason for this difference in slipperiness is purely a factor of surface material. Most foam pads have a tacky surface finish. Inflatable pads, on the other hand, usually have a sturdy synthetic fabric as the surface. Fabric on fabric (sleeping bag on inflatable pad) will stick less than fabric on foam, unless the fabrics have been treated ...


7

First things first: Has anyone else tried this? No I've not tried it. Would I use a mattress topper while camping No Why? They're heavy and awkward to move in and out of tent they'll absorb water they'y designed to sit on top of a nice flat mattress not a bumpy stone covered field (as you say) they will react differently depending on the ...


6

Piles of clothes (though not that comfortable) they do help insulate you when it's cold (one of the main things a sleeping mat does is insulate you from the ground to keep you warm, not just make it more comfortable).


2

I think it's not the material or fabric on the top it's more the shape of the pad. The most self inflatable pads are fully flat and even on top. The most other pads aren't flat because they have chambers. This gives a uneven surface of the pad. So my conclusion is: You have less friction with the inflatable flat pad because of the surface structure, even ...


2

At the risk of sounding like a grumpy old person it seems like EVERYTHING is slipperier than it used to be. I'm not sure if new stuff starts slippery and gets less so, or if things are now made more slippery. But I have bought a new tent, new sleeping pad and new sleeping bags this year and between them - I had better set up on 100& level ground. I used ...


2

According to wikipedia2 In calculating the R-value of a multi-layered installation, the R-values of the individual layers are added. I would imagine a slight diminishing return as the r-value is a laboratory measurement in ideal condition which is not quite the same as on the field (variable temperatures, moisture, air movement, etc.).


2

The foam inside the mat prevents heat loss through convection which would be the case with the air if there was nothing to prevent it moving. This forms part of the open cell vs closed cell argument for sleeping mats.


1

I have an Exped Synmat. It takes a couple of minutes to inflate it pressing on the pump, and I have used it for a full week without needing to be inflated again. Some models include fibres filling for extra insulation, so even if it is partially deflated, no part of your body is in direct contact with the cold floor.


1

I don't know how robust the waterproof bottom of your bivy bag is, but with the bivy bags I know (which are predominantly some kind of mountaineering emergency equipment) I would not want to put the sleeping pad into them. The reason is simply, that bivy bags are designed to give a good weather insulation (primarily by being waterproof and windproof) while ...



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