There has been concern about the making of a silnylon " tube tent" and condensation. Three questions,

Do you get any condensation on the mini tent?

If so, do you think making the top part of the tent with "breathable" M90 would help?

Is M90 a good choice for an enclosed tent where "breathability" is desired?

Thanks

ernie the eyeball
bsaernie@gmail.com

Edited by askernie on 10/10/2011 16:05:17 MDT.

I am 6'3" and was wondering how much longer I need to make the bivy?
Thanks
Dustin

The floor of the SMD Meteor bivy is 84" long and is about right for me with a few inches clearance in the head area. I'm 72" tall with size 12 feet and typically would use it with a size small neoair pad. On outings where weight is less critical I use a large neoair pad and it ends up being a pretty snug fit due to rounded corners on the head end.

If I'm interpreting Jamie's pattern and instructions correctly his finished floor is 76" long. Adjust as you see fit.

Here is my version of Jamie Shortt’s pattern, using .51 cuben, ultralight insect netting (both from zpacks) and M55 (thru-hiker). An added 24” side zipper is the only modification to the pattern specs. The weight of the bivy without shock cord is 3.45 oz.

For reference, inside the bivy are a 48" long, 1” thick pad, a 21 oz. MYOG quilt sized for me at 5’7”, and a Granite Gear Air Zippsack used for a pillow.

Thanks very much to Jamie for sharing a great pattern!

Edited by lagibson on 12/04/2011 18:10:12 MST.

Whoa Laurie!!!! Under 4oz! Saweeeeeeeeet!

I finally made my first "real" MYOG project, the reason I bought a sewing machine.

I used sil 2nds and ripstop from Quest, and my tweak to make this fit me was that I added 6". I'm 6' and about 180lbs, and I use a long bag, so the added length was necessary. I added it to the hood area, 3" to the mesh and 3" to the nylon hood; that way I still only used two yards of the top material.

I also made a side zip using one continuous zipper. It was a pain, but I think it was worth it. Rather than try to make the zipper do a 100 degree turn, I added a small triangle to the mesh, turning the zipper twice in smaller angles. It works quite well.


Hood end with my Sub Kilo and Z-lite.


Foot end. I also made the corners 10" high because I have size 14 feet.


Opened up.


Close up of the curve in the zipper. Someone with better sewing skills could've done much better.

Final weight: 6.7 oz without trimming the seam allowances. I haven't decided yet if I want to go back and add stitching to make them lay flat.

Thanks to Jamie for making the pattern, and thanks to everyone for posting their bivys. The discussion and pictures helped me a lot.

Jeff

Edited by j.j.81 on 01/15/2012 16:52:19 MST.

Laurie, under 4 oz. is impressive! Did you use two separate zippers? Any better photos?

I made my own. This was one of the first myog projects of mine that I have been pleased with. The fit is great. I will post pics this weekend when I get to use it. It weighs 5.4 oz with sil seconds from owfinc (used them for everything), .9 oz ripstop breathable, .9 oz noseeum netting, and a cont. coil sipper.

James,

I used two zippers; the side zipper is 24" length. The photo shows where the two closed zippers meet. Except for the side zipper, the construction of this project is very straight-forward. I'm not sure I'd go to the trouble to add the side zipper next time, as it was hard for me to do perfectly neatly.

It is LytW8 for sure. I will use a polycryo ground sheet under the thin cuben floor though. Dirty ground sheet stored in outside mesh pocket of backpack; clean bivy inside the pack.

I have read the thread a few times and ordered my material. I was just wondering, as it got a little confusing, is the current pattern design compatible with a thick pad like the neoair or will I still need to add a little bit of extra height? I'm just using the regular size pad. Took me a while to get my material from thru-hiker to aus so dont want to balls it up if i can avoid it. Cheers.

Hi Dave,

The new bivy pattern should be a little bit more roomy than the previous version however, I do think it would be a good idea for you to expand the foot box by a few inches.

You might have seen my post earlier with the bivy and neoair. I adjusted the measurements to be a bit more roomy to accommodate the neoair and sleeping bag.

Before, the measurements on the bivy were:

<--11.5"-M90--><--6.5"-bug net-->Zipper<--73"-M90-----> (top of bivy lengths)
Head: 25" ------ Zippered Middle: 36" ------- Foot: 25"(width of bivy)
<-----------------17"--------------><------73"--------> (bottom of bivy lengths)

The new dimensions are...

<--12"--M90--><--7"---bug net-->Zipper<--72"-M90-----> (top of bivy lengths)
Head: 29" ------ Zippered Middle: 36" ------- Foot: 25" (width of bivy)
<-----------------18"-------------><---------72------> (bottom of bivy lengths

MY dimensions for the Neoair bivy where as follows...

<--11.5"-M90--><--6.5"-bug net-->Zipper<--73"-M90-----> (top of bivy lengths)
Head: 35" ------ Zippered Middle: 36"-------- Foot: 28" (width of bivy)
<-----------------17"-------------><---------73"------> (bottom of bivy lengths)

I found that with the extra width at the foot, I could fit the neoair and sleeping bag snuggly. I don't think the neoair would have been so cooperative if I had used the original dimensions. Also, I wouldn't recommend folding in the corners anymore than 8" to achieve extra height, doing so will make your bivy too narrow for the boxy neoair. The extra room at the head had nothing to do with the neoair, I just wanted more room to stow things away with winter use in mind.

Let me know if that clears it up for you!

Cheers Steve,

So what height did you use at the head and foot ends of the bivy? 8"? Thanks for your dimensions! I will be using my bivy bag with a neoair all the time so based on the "snugness" would you recommend adding a little width for height, or was it not too constricting around the feet? Will hopefully have a crack with this next week :) Have only ever made fleece pants before but it doesnt look too hard. Mum is willing to oversee the operation :)

Dave.

Hi Dave,

Yes, just the 8" called for by the instructions.

I'm not sure how wide you'll need to make it. I suppose it mostly depends what you'll be using for insulation on top of the neoair. For reference, in that photo, I was using a Feathered Friends Hummingbird which is a 20F sleeping bag with a minimal footbox. When inside the bivy with sleeping bag and neoair, the bag was pressed up against the walls but there was still a small amount of wiggle room. I don't think that's necessarily a problem, but I wouldn't want it any tighter. It seems like some vacant air between the bag and bivy helps to reduce condensation and to some degree increases thermal efficiency by allowing the bag to freely loft.

Making the bivy was a pain free experience for me! Make sure to use LOTS of sewing pins to keep the material together. Silnylon and M90 have a tendency to be quite slippery and difficult to sew if you don't pin them down. A walking foot will also help if you can find one for your machine. The only tricky part for me was making the foot box look symmetrical and pretty. I'd recommend getting familiar with making this ->(http://thru-hiker.com/projects/silnylon_stuffsacks.php)<- stuff sack because that's the way you'll form the footbox. Everything else was quite intuitive.

Best of luck!

Cheers~

A big thanks to everyone on this thread--Chris and Jamie in particular. As a belated Valentine's Day present, my wife sewed me a bivy! The top is M90 (over M50 for the added breathability) and Shield silnylon, and it came out to 6.7 oz (with seam allowances double-stitched for added strength). She finished it about three weeks ago, but I decided to add a line of stitching along the zipper to keep the M90 from getting caught. So--technically--it wasn't finished until this morning. Regardless, I am a lucky man.

I decided I wanted it to be a little roomier because I use an inflatable, have large feet (size 12), and to keep the option open for fitting a winter bag. I ended up expanding the dimensions as below. Honestly it has a lot of space. The only thing I'd change if I could do it again is the netting window. I lost more of the M90 to the head wall than I expected, and I could definitely get away with a smaller window. Other than that, it's exactly what I wanted.

Here are the adjusted dimensions I used along with obligatory pictures:

Clayton,
What is your height and approx. weight? Just trying to visualize how I would fit into those dimensions. Thanks,
Steve

Hey Steve--I weigh about 220 and am 5'11" with a 46" chest and a 36" waist. Actually, here are a couple of pictures of me in the bivy. I'm using a NeoAir XLite size Regular and a GoLite Ultra 20 down quilt. They're cell phone quality and not as pretty as the DSLR pics, thus the reason I didn't include them originally.





Are you interested in making one yourself? Even though I didn't sew this one up, I watched my wife do it pretty constantly (she had to make me leave the room and do something else), and it was definitely easier than the tarp I just finished. The only thing tricky would be getting the curve of the zipper right (she really did an excellent job there).