[WTB] Bivy bag and/or tarp

[Larks]

Considering moving to a more stripped back shelter with a bivy and tarp setup.

However, before I take the plunge I’d like to see whether I can actually stand sleeping in a bivy.
So looking for a cheap bivy and/or tarp so I can get feel for things.

Weight and condition isn’t that important at this stage.
Based in Vic, but happy to pay for postage from elsewhere.

Thanks.

[Moondog55]

viewtopic.php?f=13&t=32696
I doubt you'll find a decent bivvy any cheaper than the one I have for sale.
You can buy cheap tarps at BCF or Rays or Anaconda or mail order from Wild Earth or Snowys for around $50-

[wayno]

bivy bags get really sweaty really easily... more for really cold conditions when its not going to rain much...

[willem]

I have a Exped bivy poncho for sale $95

[ribuck]

bivy bags get really sweaty really easily... more for really cold conditions when its not going to rain much...

I could not disagree more with this generalisation. I think it depends very much on the design of the bivvy bag.

For 20 years I used a Macpac Aurora, a hooped bivvy bag which was heavy by today's standards (900g). I spent over 500 nights in that bag in NSW and NZ and PNG, in all seasons and in all weathers from snow to tropical downpours. Every night was a good one (well, except for an incident with a wild dog and an incident with a snake, but comfort-wise the bag was excellent).

Then, when that bag finally expired, I bought the closest I could find - an expensive hooped bivvy of breathable fabric. I slept in it three nights and couldn't handle any more. It became clammy inside within an hour of entering, and stayed that way regardless of conditions.

So why the difference? I don't pretend to know, but the MacPac Aurora was of a design not currently found in bivvy bags. It had a thick bathtub floor of 70d nylon, and a three-layer Goretex top. The outer layer was ripstop nylon with a fairly open weave. The middle layer was Goretex. The inner layer was some type of flocked material, with quite a texture to it, and this layer may have been the key to the excellent performance of the bag. I have saved a swatch of the fabric, in case I am able to find something similar again.

I'm aware of all the discussions of the physics of condensation and dew point in bivvy bags, and yet I have hundreds of nights experience to the contrary. Go figure!

[EGM]

"ribuck" wrote
It had a thick bathtub floor of 70d nylon, and a three-layer Goretex top. The outer layer was ripstop nylon with a fairly open weave. The middle layer was Goretex. The inner layer was some type of flocked material, with quite a texture to it, and this layer may have been the key to the excellent performance of the bag. I have saved a swatch of the fabric, in case I am able to find something similar again.

Sounds to me like your describing the ToddTex fabric used in Bibler and then Black Diamond shelters.

[ribuck]

Sounds to me like your describing the ToddTex fabric used in Bibler and then Black Diamond shelters.

Thanks EGM! By using the "ToddTex" search term, I was able to look into this further.

The MacPac Aurora bivvy used a real GoreTex product. It seems that Gore stopped making this fabric when the fabric couldn't meet the new California flame-retardant restrictions for tents. A pity, since people don't cook inside a bivvy bag (unlike, say, in the vestibule of a tent). I suppose a desperate smoker might be tempted to light a fag in their bivvy bag during a storm though.

The flocked inner layer seems to improve the wet-weather performance in a few ways, but the main reasons seem to be: (1) Its texture provides just enough thickness to keep your skin away from the layer where the condensation forms, and (2) The inner layer is hydrophobic, so any condensation that forms won't return inside but will seep down until it drips out at the join between the "roof" and the bathtub floor, at which point the GoreTex layer is outside the bathtub layer.

Regardless of the reasons, it worked really well - with the penalty of some extra weight. Anyway I'm past bivvy bags now. I'm too old to do the specific contortion that was required to keep everything dry when emerging from the bivvy bag during heavy rain - and anyway some modern tents are lighter than that bivvy bag was.

[commando]

To me a bivvy bag was something you put a sleeping bag in whilst tied to a rock wall or bivuoacing on a ledge.
The word now loosely describes a tunnel tent.

[pfeutry]

Found your tarp? Send me a pm if you haven't