Using silnylon for quilt footbox?

I am sure others will chime in but I would not want any part of a quilt (or sleeping bag)
Shelled in a non breatheable material (except if using a VBL)

> silnylon for the outer shell of the footbox to keep out condensation from the tent walls,
Totally BAD idea.
All you will achieve is tons of condensation of sweat from your feet on the inside of the shell. Not just a few times, but every night.

If you want to use the silnylon, use it on the INNER layer of the shell, to keep moisture (sweat) out of the insulation. If you do that it is called a vapour barrier liner (VBL), but really that should only be used below about -10 C.

Cheers

I am guessing your 0.9 oz/sq yd silnylon is Membrane Sil from Ripstop by the Roll? If so, then the finished fabric weight is actually 1.05 oz/sq yd

The DWR on Argon 67 is decent but not great – I think the Pertex GL from ZPacks has better DWR (but it is also less breathable). Try running some water over the fabric to see if it will be good enough for you.

Maybe you can find someone that can sell you a bit of eVent fabric. When Javan Dempsey made me a custom quilt, he offered that as an option, which would have been a good idea since often condensation from a shelter can run to your footbox.

Depending on how big of a piece you need, I have a short remnant of 2 layer event in a royal blue that I'd be happy to donate for the cause. Shouldn't be over $2-3 for shipping.

Thanks for the feedback. Rogers, that was my concern, but it's good to hear from someone with more experience & expertise that it wouldn't work out well.

Nathan, I'd need a pretty big piece (86"x22") of eVent for the footbox. If you don't have any other use for the eVent, I'd be glad to have it to make some rain mitts.

I ordered some taffeta 0.66oz/yd "Membrane 10" from Ripstop By The Roll for this double quilt and decided to save the Argon for a single quilt. I haven't seen any comments here on BPL about the non-sil Membrane and am curious to see how it compares in feel, breathability, and DWR to Argon.