I was thinking of buying a pair of VB socks for winter camping. I carry a couple of sil-nylon stuff sacks for my sleeping quilt and down jacket, and wondered if they would work?
They are not seam sealed.
Should i wear a thin liner sock? What material is best for a liner sock?

Works Great for sleeping/camp use. Just put the sack on bare skin and put a thick sock over the top. If you're squeamish about the silnylon on your skin or you want to try it while hiking, you can use a very thin synthetic liner sock on the inside.

Bread Bags also work, though they are not very durable.

-Mike

Thanks Mike.
I wouldn't wear them hiking, as they would be in my pack holding gear. It's just for sleeping. I've got myself a pair of Feathered Friends down booties, and i don't want to sweat into the down.
I never thought of using sil-nylon bags whilst hiking. Do you think they would be comfortable in my Inov8's?

I'm not sure how comfortable this would be while hiking. Firstly, they are quite slippery, secondly, the excess material (compared to sock, which fits better) could hurt your feet.

Silnylon also isn't completely waterproof, it could be used as a VB, but won't keep your feet dry.

Will work great....but WHEW, your gear will stink!!!!! :)

I think it's a great idea. I would suggest turning the stuff sacks inside out first, especially if it's for your sleeping bag. This way, the sweat from your feet doesn't get on your sleeping bag when you re-stuff it.

Thanks guys.
Michael. That's a great point about turning them inside out. I hadn't even thought of that. :)

Mike, Have you any good links to how VB layers work? I read the article in TGO, but it seemed that all it does is keep your insulation dry, not add any extra warmth. I got the impression I'd not understood it properly, as I can't see how it would help in conditions where the insulation isn't getting wet.

Cheers!

It creates a micro-climate next to the skin. More info at RBH Designs. I'm sure there is loads of info in the forum here, if you search. Not sure i understand it completely, so i don't want to give you any wrong information! :)

I'll take a weak crack at this and hope that someone else corrects any mistakes.

When your body sweats and that sweat evaporates, it cools the skin. This is because it takes energy to convert liquid water into vapor. That energy comes from your body heat.

A vapor barrier won't let this evaporation take place. Also, here's the really mysterious part, supposedly your body senses when your skin is saturated and quits sweating.

Bottom line is that more of your body heat is preserved by eliminating this vapoizing process. It's not that the vapor barrier is providing insulation.

Michael, what I understand from all the research I have done is that you are correct about VB preventing evaporative cooling.

Just for comparison think how much warmth a wind shirt provides. It does so by slowing down evaporative heat loss. VB completely stops evaporative heat loss. So it is very warm.

>Also, here's the really mysterious part, supposedly your body senses when your skin is saturated and quits sweating.

I am not sure about the mysterious part.

Use of VB requires high intelligence. I think the key is to control your sweating and keeping your body cool. This is achieved by constant adjustment of ventilation of your clothing.

For best results, you should wear the thinnest/lightest wicking base layer under your VB.

Edited by huzefa on 09/10/2008 18:14:01 MDT.

The other key thing is that it dramatically reduces moisture getting into your insulation (since it's a waterproof barrier). This helps prevent insulation collapse and added weight due to water and ice crystals within the insulation.

Cheers guys, stopping evaporative heat loss makes sense, having felt the benefits of a windshirt!
I'm not sure about it stopping you sweating? The article I read said if your temperature was ok, it would stop you producing the sweat you need to keep your sking moist, once a certain level was achieved. If you are hot in a VB, surely you would sweat like hell?
If you are in a damp but not cold (i.e above freezing) climate and you generally have no problem with moisture in your insulation, would a VB still improve the insulation or just help by reducing the evaporative heat loss? Is VB really just for sub-zero use.

> I'm not sure about it stopping you sweating? The article I read said if your temperature was ok, it would stop you producing the sweat you need to keep your sking moist, once a certain level was achieved.
I don't think it stops you sweating directly. I think it helps keep you from losing heat by evaporation. And ...

> If you are hot in a VB, surely you would sweat like hell?
Precisely. Sleeping cool is advised.

> If you are in a damp but not cold (i.e above freezing) climate and you generally have no problem with moisture in your insulation, would a VB still improve the insulation or just help by reducing the evaporative heat loss?
Stephenson advocates wearing VB clothing under warmer conditions than most would (could?) tolerate. Few agree with him, afaik.

> Is VB really just for sub-zero use.
I think it is often suggested for below ABOUT -10 C, but I haven't seen many suggest it for much warmer than that. However, doubtless some use it under warmer conditions - it might depend on the individual and how much he sweats.

Cheers

>If you are hot in a VB, surely you would sweat like hell?

Yes, you will. ventilate!

>If you are in a damp but not cold (i.e above freezing) climate and you generally have no problem with moisture in your insulation, would a VB still improve the insulation or just help by reducing the evaporative heat loss?

sure it it will help. Any amount of moisture in your insulation will affect its warmth.

>Is VB really just for sub-zero use.
IIRC Bill Fornshell has experimented with using VB >40F. If you try search you may find it. Hint try searching 'RBH' or 'fuzzy' and look for post by Bill fornshell.

Ryan Jordan also experimented with VB on his SUL winter challenge. He got too hot and it didnt work out for him. Hint: IIRC Ryan's post trip report is in the last 3 pages of the SUL winter challenge thread.

I think it didnt work out for him because the clothing he took wasnt very versatile. IIRC he took RBH vaprthm jacket and pant. It turned out to be too warm. Instead if he had taken thin baselayer and silnylon jacket/pants it is more likely that it would have worked out. Removing the VB pants or wearing shorts instead would have helped him keep himself cool.

Roger beat me to it...!

Ryan Jordan also experimented with VB on his SUL winter challenge. He got too hot and it didn't work out for him. ...
I think it didn't work out for him because the clothing he took wasn't very versatile.

True. But to be fair, the weight limitations of SUL leave little room for versatility. Indeed, it's very hard to be "cold weather versatile" at UL weights. Even Andrew Skurka's Ultralight in the Nation's Icebox base weight was 13+ pounds (along with 11+ worn/carried)

Huzefa,

Hi, yes I have something posted here about how I was using the RBH VB things but that thread or comments seem to be lost in this ??? forum programing.

I started posting all my threads also on my BLOG so I could fine them when I wanted to update a project.

This is the link to my
RBH - VB Comments

My BLOG is free.