Questions about a Solid/Partially-Solid Inner for a ‘Mid

If you want to be warmer, it would weigh less to just have thicker sleeping bag

Argon 67 from dutchweargear or Nobul1 or 2 from tittaniumgoat would make a good inner. Fairly breathable and very light weight.

If you're making it mostly for winter use, then think spindrift. I'd go with fully solid and a mesh vent at the peak that can be covered by solid fabric if needed. I would aim for an inner configuration and size such that you plan to pitch the mid with the edge a couple inches off the ground for air circulation in hopes of reducing condensation/frost on the inside of the mid. With a full solid inner you don't need the outer to seal tight to the ground to keep spindrift off, and you do want all the ventilation you can get between outer and inner. As others have mentioned you can get more added warmth by taking a warmer sleeping bag instead of an inner; but that only applies if you are in the bag. the nice thing about an inner tent is that while you are are awake and semi-active in there – cooking, eating, organizing gear and such – you will warm up the interior more than you would be able to with a single skin, and it's just a more comfortable environment.
As to fabric I'd get the most breathable and lightest – I wouldn't concern myself with wind resistance at all, as any solid fabric will be fine in that regard.
I just got some argon 67 for a project I hope to get to, and just doing the "hold it over the mouth and breathe through it" test, it seems pretty breathable.

Oh, and color – I like yellow or gold the best for a winter inner. Nice and bright on those grey days. White is okay but not as cheerful.

I really would NOT want to use a downproof calendared fabric unless serious amounts of mesh are used. Especially on the sides where it might be close to my face. Too low a CFM. It will much more easily get condensation in freezing conditions IME. I'd use the lightest uncalendared breathable fabric (like is used by the tent manufacturers)

Will the highly breathable fabrics like Nobull and Argon really keep the wind out? I was camping along the Missouri River last winter in a borrowed shelter that we couldn't pitch quite down to the ground, and the wind gusts inside were occasionally strong enough to blow a fair amount of warmth out of my quilt.

One of the reasons I'm interested in a solidish inner is that my insulation shell is very lightweight and breathable, which I quite like for for versalitility from its stated temp range on upward. Once I eliminate the drafts, its warm for even lower. (That's also the reason I don't want to add more down to the sleep system–short of getting a new bag, which would of course help but cost a lot of money I don't want to spend.)

+1 for what Paul said.

"the nice thing about an inner tent is that while you are are awake and semi-active in there – cooking, eating, organizing gear and such – you will warm up the interior more than you would be able to with a single skin, and it's just a more comfortable environment."

My wife and I would strongly second this point in particular.

Edit: Forgot to add that there isn't much, if any, weight penalty for a solid fabric inner because today's solid fabric is about as light per square yard as mosquito netting. There is a little weight added if you want to include a coverable window in the solid fabric.

Based on the feedback here (and on the MLD Facebook page), my current plans are to sew up a partially-solid inner using Argon 67 for the side walls. Since the roll width of the fabric is 58″ usuable, I should be able to get (with seam allowances) 28″ of fabric along the large sides, leaving about 14 inches of netting to take it to the top. Basically, the bottom two-thirds would be Argon 67 and the top 1/3 nanoseeum mesh.

Here’s a Sketch-Up of my plans as of now:

I’d like to order the fabric soon, as I want to try to make this over the Thanksgiving holidays, when I’m off of work. But before I do, a few final questions:

1. What do you think of the fabric choice for Argon 67? Are there other fabrics I should be considering?

2. How do the dimensions look? Is that enough netting at the top? Too much?

Thanks in advance. Your thoughts have really been helpful.

EDIT: Oh, and I forgot to mention that I’m now thinking about a solo inner rather than a duo.

How are laying out the 58" wide roll of fabric? I notice that 2' 4" length of long side + 2' 6" width of short side exactly equals 58".

There is a slight difference between lengthwise along the roll of fabric and width wise (warp and weft) so you might want both long sides and short sides to go the same.

You could use 7' 6" of argon with the two long side pieces, and 3' 3 7/16" of argon with the short side pieces.

Are you sure 7' 6" is long enough? You lose at least a foot on each side so that's 5' 6". My mid is 9', 5' high, which is comfortable – could be a little shorter.

Jerry, what do you mean by "you lose at least a foot on each side"? Currently, in summer I use a TarpTent SS2 when camping with others, and I don't find the 86" inner to be a problem. I'm 5'11".

I based the length off of the MLD specs for their Solo InnerNet. Since I'd be using this with a Duomid (or, somewhat possibly, a Solomid XL), the length seemed appropriate.

EDIT: FYI, the Duomid is 104" long and the Solomid XL 110".

Also, that's an excellent idea about how to use the fabric. I'll be playing with how to arrange the pieces soon, once I decide on a fabric.

"Jerry, what do you mean by "you lose at least a foot on each side"? Currently, in summer I use a TarpTent SS2 when camping with others, and I don't find the 86" inner to be a problem. I'm 5'11"."

if you're happy with what you have, then nevermind

at the extreme length, 7' 6", the "roof" is against the ground so you can't put your feet or head there.

at about 1' from the edge, the roof is about 1' above the ground, so if your feet or head are there, there's a foot of room before they touch the roof, so that's about usable

if you push that, then you'll be touching the roof, which might have condensation on it so you get wet

Note, there are five-inch sidewalls before the inner starts going in, and I'm not sure that I have any other options on length with the size of either shelter.

Anyway, I have a MLD Solo InnerNet already that's this size, and I'm fine with it as well.

I assume you are still like the Argon 67 for fabric? What do you think about the size of the mesh vent at the top?

I haven't used argon67, but others have. I think that's what I would get.

Nobul1 or nobul2 would be equally good if you didn't care about down leakage.

If the Nobuls leak down, maybe they're more breathable? Probably over thinking…

I don't have a lot of experience with vents, but that looks like a big vent which is good.

oh, 5 inch sidewalls – and you're already happy so nevermind

I made an inner for my pyramid tarp using Argon 67 for about 20 vertical inches of the wall (with the rest being nylon tulle). This lets me see outside when I sit up, but it blocks the wind when sleeping. It's working out well so far. I had one frosty night where condensation and frost formed on my tarp, but nothing on the inner

The Argon 67 I used was kind of dark (the green color). To help make up for this, I used bright blue silnylon for the floor.