Feb 3, 2009 at 6:00 pm #1233786
I'm considering making an inner fabric tent for winter use for the MLD DuoMid. Has anyone used 1443 tyvek for such an application? It's ~ 1.18 ounces/yd^2 (~40 g/m^2), breathable, and water resistant. Not sure how much less breathable it would be compared to thin nylon with a DWR? what do you think?
Also some kitebuilding companies have 0.75 osy ripstop fabrics… not sure if they are coated… at that weight I don't think they would be. Think this is getting to light for inner tents?
Part 34xx54 – 3/4 oz. Ripstop Nylon – 54" wide. General Purpose kite cloth, Grade 'A' only. Price: $6.85/ydFeb 4, 2009 at 1:36 pm #1475388
Just an update:
1) e-mail the kite building site and they said all of their ripstop was coated so that it would not be breathable… darn…
2) e-mailed AYCE at Thru-Hiker and he agreed that momentum would not be a good choice for an inner tent
3)sounds like the 1.1 osy ripstop nylon is the most frequently used…
4) anyone have any thoughts about 1443 tyvek as an inner tent?Feb 4, 2009 at 1:43 pm #1475391
"2) e-mailed AYCE at Thru-Hiker and he agreed that momentum would not be a good choice for an inner tent"
What's wrong with momentum as an inner tent? It's been recommended in other threads.Feb 4, 2009 at 3:53 pm #1475438
Nia – not exactly sure why not. Here's the quote from AYCE over at Thru-Hiker: "It would not be a good choice. Momentum-MR is a soft-goods shell material for things like apparel and sleeping bags."
Brad Groves in THISthread had suggested that since momentum was calendared it may have trouble with condensation.Feb 4, 2009 at 4:19 pm #1475440
> e-mail the kite building site and they said all of their ripstop was coated
Yes, a LOT of very light synthetic fabrics have an acrylic coating **just to keep the weave together**.
Caution: acrylic is NOT a waterproof coating, just a 'stick it all together' coating. However, it does tend to reduce any airflow to nearly zero. Good for parachutes maybe and for kites; not good for most outdoors gear.
> momentum would not be a good choice for an inner tent
Why? Yes, Momentum is calendared on one surface, and that will reduce the air flow somewhat. But it IS used for sleeping bags where some air movement is crucial to letting the water vapour out. Also it has a a good DWR on it. So I cannot see why it would not make quite a good inner tent fabric. It may be a little more expensive, but in the quantities used by an MYOG enthusiast the differential is trivial.
> 1443 tyvek as an inner tent
Welll, one thing is for sure: it will NOT breathe nearly as well as Momentum! A non-breathing inner tent … with me inside it?
> 1.1 osy ripstop nylon is the most frequently used.
Well, yes. I use 32 gsm (0.92 oz) fabric from Carrington Mills (UK) for my inner tents: it has worked excellently. If I had Momentum fabric I would be happy to use it.
But I would NOT use Tyvek: it does not pass air. Could be deadly!
CheersFeb 4, 2009 at 4:51 pm #1475451
Thanks Roger! Appreciate the info…Feb 4, 2009 at 7:59 pm #1475517
I thought tyvek was breathable, which is why the Sublite was made from it. Am I confused?Feb 4, 2009 at 11:24 pm #1475543
No, you aren't as confused as much as I am guilty of poor expression. Tyvek is breathable in the sense it passes water vapour; it is not air-porous.
I have edited my posting.
CheersFeb 5, 2009 at 9:39 am #1475616
For the record, what I ineloquently tried to distinguish was that, given two completely equivalent fabrics, one calendared and one not, the non-calendared fabric would breathe better. I have a couple things made in Momentum and agree that it does breathe reasonably well… I do wonder about things such as tear strength and overall durability of the material if used in a tent, but then I don't think those are valid concerns given the state of the market technology. Roger, is the .92 oz fabric from Carrington that you use calendared? I don't think it's a deal-breaker one way or the other, but we might as well consider all aspects of proposed materials…Feb 5, 2009 at 9:48 am #1475617
@owareLocale: Steptoe Butte
All the woven nylons being discussed are
Just some are done at a higher temperature.Feb 5, 2009 at 12:34 pm #1475658
@richard295Locale: San Francisco Bay Area
1443 Tyvek is a poor choice relative to ripstop nylon for an inner tent. Compared with most textile fabrics, the air permeability of Tyvek Types 10 and 14 is low. Approximately 43x more air or water vapor will pass through a ripstop nylon inner tent versus the average Tyvek inner tent.Feb 5, 2009 at 1:47 pm #1475681
> Roger, is the .92 oz fabric from Carrington that you use calendared?
Not as far as I could see.
CheersFeb 5, 2009 at 2:46 pm #1475691
Thanks all – very informative thread… Looks like it has boiled down to 1.1osy ripstop nylon as the best choice (since it's commonly available in the US).Feb 5, 2009 at 5:40 pm #1475739
I think I can almost see you wince when I mention this, but…
Silk came up in another thread again. I know how much you like natural fibers in general, and that you have to replace your silk bag liners periodically. But how do you think a silk would do sewn into a tent canopy? Assuming you didn't sew a single layer simple seam :) Would there really be too much tention (sorry, spelling intentional) for the silk to hold up? I would think that as long as you dry the tent thoroughly before storage it would last decently well. Going from Mark's calcs, 4.5mm silk should come in at ~0.58 ounces and quite breathable…Feb 5, 2009 at 7:22 pm #1475760
You haven't defined the problem yet. Are you making an inner tent for 3-season comfort, or as a bug shelter, or to keep a howling snow storm out?
4.5 mm silk is rather porous …
CheersFeb 6, 2009 at 8:08 am #1475853
Hmmm. Good question. Brian, what do you want your inner to do? Is it primarily bug protection? Or are you trying to keep out blowing sand or spindrift?Feb 6, 2009 at 10:59 am #1475876
My goal is to prevent spindrift/major gusts from entering the sleeping area, increase the warmth a bit, and avoiding the need for a bivy. When I figure out how to export a google sketchup drawing as a jpg I'll post my plans for the inner shelter.Feb 6, 2009 at 11:15 am #1475881
Here is my concept for an inner tent for the DuoMid. 7'2" long 4' deep, 5" tall silnylon floor, 1.1osy ripstop nylon walls, 4'3" from peak to floor, vents at each end and at top, triangular silnylon piece zipped between doors to make cooking porch (when it's nice out).Feb 6, 2009 at 11:18 am #1475882
oops… image didn't load… trying again:Feb 6, 2009 at 11:22 am #1475883
from the side:Feb 6, 2009 at 2:08 pm #1475925
> My goal is to prevent spindrift/major gusts from entering the sleeping area,
Hum … that leaves me a little doubtful about the 4.5 mm silk. The stuff is not designed for that sort of application. It is more suited to an elegant but diaphanous negligee …
I guess you could try to make the inner tent such that you could fairly easily replace the upper part of the inner tent. A single seam line between upper part and floor maybe. After all, field testing is what counts.
CheersFeb 6, 2009 at 2:10 pm #1475927
I see that you have vertical bathtub walls. very good – but how are you going to keep the bathtub in place inside the tent, and how are you going to keep the bathtub walls upright? All possible, and I have done that, but what are your plans?
CheersFeb 6, 2009 at 6:03 pm #1475972
I was thinking of sewing in some 5 inch tall small diameter tubes (aluminum, Ti, CF, etc) on the uprights and then tie them on top and bottom with guyline to the four corners of the tarp. Something like this:Feb 6, 2009 at 7:54 pm #1475987
If you want to go down the CF rod path, visit some Kite web sites. They have thin CF rod, very light, quite cheap. You really do not need large diameter.
CheersFeb 7, 2009 at 8:43 am #1476037
@owareLocale: Steptoe Butte
Aw shucks, now you're makin it too hard.
When I've made inner tents for pyramids, I like to
increase the floor dimensions a tad and continue
the angle of the upper tent liner with the coated
"bathtub" side piece.
Run a cord under the fly out to the peg to keep it taut.
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