alternate for bivy – super duper cheap?

Check out this Tyvek Bivy thread. You can glue the tyvek together with spray adhesive, so all you need are skills you learned in kindergarten (cut and paste) ;-)
http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=12370&disable_pagination=1

I was thinking of doing something similar. GossamerGear sells 2-packs of polycyro groundcloth (1oz or so each). I was thinking I could throw one over me to keep off light rain spray (maybe with a Hexamid, which I was thinking of buying).

Doubt it'd be great it really nasty conditions, but might work well for normal conditions. Thoughts?

You can buy durable ground sheet material, or you can buy the cheapest and lightest thing. That is probably a 9'x12' painter's plastic drop cloth in the thinnest piece that your local Home Depot store sells. Once you get it home, you can cut it into two pieces, just depending exactly how you intend to use it. If so, you have two pieces each 9'x6', and that is large enough to cover lots of things in a wet situation.

–B.G.–

i was think along the same lines but with polycro. tyvek is not fully waterproof and does not pack as tightly as polycro. but i think tyvek is tougher if you had to guy it out in windy conditions. never tried either though, let us know how it goes.

I live in an area that's much more humid than you do, but even if I were in the desert, I still wouldn't want to cover my sleeping bag with any kind of plastic all night long. You'll almost certainly wake up with a soaking wet bag from condensation. Tyvek or any breathable fabric would work much better IMO. You don't see anyone selling plastic bivy sacks do you? There's a good reason for that.

Or maybe better yet, just put a really good coat of DWR on your bag (the stuff you set into the fabric in the dryer, not just the spray on stuff) and do a really good job setting up your shelter. Unless you are using a very minimalist tarp, you can stay dry without a bivy sack.

Adventure medical sells 2 emergency blanket bivys for pretty cheap..

Good advice in this thread already.

i'd vote for no bivy or cover at all. Spindrift is highly unlikely in the summer in the sierra. Dew isn't a big deal, you'll almost always be able to dry out during the day. Most nights aren't dewy, and if they are, sleep under trees or your tarp to mitigate the problem.

+1 on this comment. Get good at pitching your tarp; you will be surprised at how effective it can be.

An alternative to tyvek that I've had good luck with if you're expecting nasty storms and the like is to wrap up in a Driducks poncho. It breaths really well and is completely waterproof. I paired it with a GG ground cloth.

Keep in mind that by "good luck" I mean it didn't rain as hard as I thought it was going to but it did keep the splash off of me under a 5×8 some nights.

Thanks all!

Brian Camprini…that thread is perfect! That is exactly what I'm thinking of. My first attempt probably will be a bit more crude than those ones, but it's good to know that for the most part, the tyvek material WILL stand up to relatively frequent use. Interesting too that in some ways, it seems to perform better than traditional bivy materials(sil, event, momentum etc)

I'm steering away from anything like polycro simply for breathabilty reasons.

Thanks again all. I'll resurrect this thread and post some photos if/when I actually get around to this.