UL Inner Tent Fabric

The Hubba Hubba HP is lighter than the regular Hubba Hubba but I don't think it's because of the inner fabric as you would initially think. The HP uses a lighter nylon for the fly (20D vs. 40D) which saves a lot of weight and more than overcomes the heavier inner tent. As per the MSR site, the HP inner is also made from 20D nylon.

Ah, thanks, Dan.

Ben calendered 20d with DWR like momentum 90 might be worth looking at. It has lower breath-ability so it sounds like what you may be looking for. If you need ventilation thru-hiker.com has nano-see-um mesh at .7oz/yd2. Thru-hiker has "momentum 90", Titanium goat has the same 20d if you email them and OWFINC will be getting it in a few months. With sub 1oz material that would be a very light inner tent!

Hi Bender:

As mentioned, I have an "all mesh" inner tent which I'd like to replace with uncoated, highly breathable nylon (or poly) — the lightest that will still block sand and winds. I will also cut out a few zippable, mesh-backed vents. A concern is that lower breathability and lack of vents will produce too much condensation.

Given the above, which nylon or poly fabric would you recommend? And what is the weight as compared to noseeum fabric? Thanks!

Ben,
Maybe a compromise could be reached by having the lower 12 inches or so be fabric to reduce breezes hitting you and the upper half or two/thirds is mesh for breathability and lightness? The all-fabric walls would be warmer. Also look at maybe using fabric in the ceiling. Three of us once spent a miserable 24 hours with all mesh inner tent. The condensation would form on the fly and poles, and then drip down on the mesh. When it hit the mesh it turned into a fine spray or continued to drip down on our down bags. It was maddening to watch the drips slowly form and drip on you. The mesh kept you from being able to wipe the water with a rag before it dripped on you. That was a trip, we had already grown tired of reading the Dr. Bonner's label… A fabric ceiling would have deflected and absorbed the moisture and become heavier. I think the water might have spread out better accross the fabric than the mesh. Scott

I've wondered about somehow making the lighter cuben fabrics breatheable – perhaps repeated washings in a top-loader, for example. The .33 oz./yd. cuben should easily serve the purpose, but needs to have the ability to pass gas. I also wonder if there is a way to roll micro-perforations in the mylar film in order to serve this purpose.

Micro-perforations –

Cuben doesn't wick either, so any condensation would have to literally into a hole and capillary through to the other side.

More significantly, Cuben wouldn't get along well with a bunch of holes.

Hi Ben you might try contacting Seattle Fabrics. They seem easier to reach by phone. I'm sure there are other outdoor fabric suppliers as well that have the info and material readily available.

Very interested in what you found out as there are some tents I'd be more interested in if I could replace the walls of the inner, or at least the bottom half, with breathable fabric.

@Greg – breathable, microporous film fabrics transpire moisture vapor in a more "mechanical" way, through tiny "holes," if you will, which move based on temperature differentials chiefly. Contrarily, I have heard and observed that cuben takes pin-holes rather well and will not spread or stretch like other fabrics. The strength is in the fibers and the mylar membrane would be the only thing pierced, so it should maintain it's integrity to a large degree. The cleanest way, of course, would be if the manufacturer could/would laminate a semi-permeable membrane to the spectra web.

Scott:

My interest in an "all-fabric" inner with closable windows is also because I sometimes camp in sandy desert stretches.

Curious, what tent were you using when you experienced those annoying drips?

EJ:

Thanks for the tip. I do wonder what breathable fellow hikers use for their inner tents that they deem the lightest?

My guess is that uncoated Momentum 90 is the best you can do for a solid fabric without doing a custom job. I've wondered about poking holes in Cuben and it seems like it would work. I'm not sure exactly how to do it, though. You could just poke with a thumbtack all over the place, but that seems tedious.

I guess you could take a board, drive a bunch of nails through it, then press it on the Cuban. With a small section (say 1 foot by 1 foot) it wouldn't take too long. Too bad the stuff is so expensive, or you could experiment. Maybe some folks with scraps are willing to give it a try.

Actually, now that I think about, maybe silk would be lighter.

Yeah, I thought of silk also, but I don't know how well it would hold up. That would certainly get style points, though. Combine with a hemp fly and bamboo/cane poles and you've got a full-on eco shelter.

My money is on the lightest cuben intact, with enough high and low coverable mesh panels for breathability. Large Near vertical panels at both ends and high above the door.
Condensation on the inside of the inner happens sometimes with any fabric.
In a wind in the desert you would close the upwind vent completely and reduce the others to taste