Sound-transparency, water-shedding and "stretchy-ness" would be
ideal. The later if flapping is to be minimized.
This is probably a more complicated solution than many would prefer,
but as some sort of frame to stretch the fabric on would probably be
necessary, one could make this strong and add grommets around the
perimeter for stretching water-shedding fabric with small bungy
cords. EMT conduit? I'm thinking somewhere around 3' X 3' or
slightly larger. The diffusion material (which should be less prone
to flapping) could go on top of the water-shedding fabric, pulled
taut and separated an inch or two. This "roof" is then pitched so the
water rolls off and is positioned several feet above the rig. The big
draw-backs I can see is the need to have nearby trees or posts for
suspending it and you might need a water directing "gutter" for
downpours to reduce the pattering.
As per fabric choice, with this approach, as long as there are no
seams in the water-shedding fabric and the diffusion material doesn't
touch the taut fabric, materials such tent nylon should work fine.
Thanks for the tip, Justin. Here's another bushwalking.org resource,
part of it describing types of water repellent treatments:
http://www.bushwalking.org.au/FAQ/FAQ_Fabrics.htm It has a link to a
fabrics expert. Rob D.
= = = = =
At 6:02 AM -0800 1/31/09, Lou Judson wrote:
>Further googling on the interesting material brought up this:
>
>Ventile's chief attributes are its soft hand, windproof quality, and
>high breathability. It works great in cool-to-cold, dry conditions.
>It's also fine when it's cold and snowy out. But it works less well
>when it's raining, for instance. The stuff has good water repellency,
>but in time it will start to absorb water. When that happens, a
>jacket made of Ventile quickly becomes a heavy, soggy mess that can
>take days to dry. I used to joke that my Ventile jacket had the water
>repellency of a sponge: Meaning, it could absorb only so much.
>
>frpm
><<http://outside.away.com/gear/gearguy/200309/20030905.html>http://outside.away.com/gear/gearguy/200309/20030905.html>
>
>so I don'tknow about waterproofness. But it loks interesting, if
>expensive.
>
>The manufacturer's website say it is "weatherproof" if not "Waterproof".
>
><<http://www.ventile.co.uk/>http://www.ventile.co.uk/>
>
>But hey, a nice hand is good to have!
>
><L>
>
>On Jan 30, 2009, at 5:55 PM, justinasia wrote:
>
>I don't mean to butt in on the conversation as I have no expertise on
>this matter, but I thought to mention a fabric to you in case it may
>be useful. "Ventile". It was developed during the Second World War, in
>England. It is pure cotton only, but is waterproof and quiet. Also
>great for quiet waterproof jackets so some of you might be interested
>in it generally too.
>
><http://en.wikipedia.org/wiki/Ventile>http://en.wikipedia.org/wiki/Ventile
>
>Justin
>
>
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