Saturday, April 25, 2015

More Reflections on a DIY / MYOG Synthetic Overbag v2.0: the Saco Verde

*Note:  I have since field tested El Saco Verde and given a lot more thought to the design of this project.  Please see updates below.

Last year I wrote about and showed some pictures off of a somewhat unique/specialized DIY/MYOG project for an avid Ultralight backpacker, which is my version of a Climashield APEX sleeping bag that I named Saco Rojo.  I was and still am quite happy with the way it came out, however being the obsessive backpacker that I am, I thought that there was still some room for improvement.  As noted in my previous reflections, I had always intended to make two of these sleeping bags--one for me and one for my wife.  So I already had another silk liner, as well as some more insulation (which I bought from Thru-Hiker), and also some more M90 for the top shell of the bag.

I first started my new modifications for this next bag by sewing up the silk liner by hand, turning it into a big tube rather than a sheet with a side-entry.  Then I cut off the top of the liner to create a top entry for this silk tube.  Next I did what I wish I would have done originally when making my first bag--though this is really knit-picky fine tuning, I admit, as the M90 fabric works quite well as a shell and is pretty damn light.  I ordered some ARGON 67 from Dutchware Gear in a lovely dark green.  

I received the fabric and was very impressed by my initial impressions... but then I had to put the whole project on the back-burner, as one does when life gets busy.  Not to mention that I had to get our sewing machine serviced before we could continue anyhow, which was done recently, and for cheaper than I thought (so no need to buy a new machine--Woohoo!).

Yet finally this past week my wife and I got a bit of free time to work together and make version 2.0 of this project, Saco Verde.  I also helped a lot more with this one by doing the tedious work of pinning the shell and insulation to the silk liner.  This time it only took my wife a half hour or so to run the bag through the machine, and our work was complete.  Here she blows, and I am very happy with the finished product:


I'm sure some of you are wondering about the specs (especially the weight for all you gram geeks), so here they are:

Weight - 285g / 10.1oz
Length - 190cm /  74.8in
Width - 64cm / 25.2in

Used in combination with either of my bags, here is what the total weight would be:

Zpacks 40 + Saco Verde + big stuff sack for both = 715g / 25.2oz
Zpacks 20 + Saco Verde + two stuff sacks = 930g / 32.8oz

Not only am I happy with the overall quality and improvements to the design, I am also happy to break the 300g / 10.6oz weight barrier.  Saco Rojo for instance is 311g / 11oz.  I have seen some other SUL/XUL quilts out there, such as Jason's 354g / 12.5oz DIY quilt made out of 2.5 Climashield Apex and NoBull1 fabric.  Not sure how to rate the temperature for either of our bags, but I'd be willing to give a good educated guess that they would work well for me for temps of 11C / 52F to 19C / 66F.  Right in the middle at 15C / 59F is then probably the ideal comfort temp, but I'd like to of course give some further testing this summer to see the limits and ideal temps for Saco Verde.

You might notice that in the above picture, it looks like there's something inside the bag.  Now I had initially intended for these two bags to be liners to use inside of our down sleeping bags, however after giving more thought to it, and seeing how relatively big these bags came out, I decided to see how my down bags would fit on the inside.  If they fit well, then this bag would kill an additional bird with a stone, as is said.

And as it turns out, not only does my Zpacks 40 bag fit well inside of it, so does my Zpacks 20 bag, to my surprise.  I did make sure to get inside and test out how it would feel to be inside of both bags (you can read more about both bags here).  *The 40 bag fits with a bit of room to spare, but unsurprisingly the 20 bag is a bit tight, but only slightly, and only in the shoulders.  I am very excited about this, because now this extends the usefulness of these bags by one more significant factor: vapor/moisture wicking to keep the down drier. 

*Update 12/05/2015:  After testing out the Saco Verde/Zpacks 40 combo, I've concluded that it would be too small to use with my 20 bag.  However it works well with the 40.  More on this below.

First some more pictures of the stuffed Saco Verde before I explain further:


Top view with the Zpacks 40 bag inside.

Stuffed with the Zpacks 20 bag.

And finally the top view of the 20 bag inside.

So first before discussing this new dynamic of these bags, let's review the benefits of the bags:


  • 1.  At only around 40 bucks each, they are cheap.
  • 2.  While the materials can be a bit tricky to work with, if you do a good job pinning the fabrics together, sewing is relatively quick and easy.  Granted, the pinning is kind of a pain in the neck.
  • 3.  They are pretty damn light.
  • 4.  They would work well as a warm weather / summer sleeping bag on their own.
  • 5.  Combined as either a sleeping bag liner or overbag, they provide a significant bump in warmth.
  • 6.  The materials are relatively durable for what they are made for as part of a sleep system, and if they are damaged they can be fixed easier than say a down bag.
  • 7.  They don't absorb very much moisture and provide warmth even if somewhat wet.
  • 8.  The design is fully enclosed, which prevents drafts and holds in warmth more effectively than a quilt.
  • 9.  Making your own gear is cool.

...And the new benefit if used as an overbag, which is somewhat of a issue/puzzle for backpackers using down bags in colder temperatures, which I will soon discuss in more detail is:

  • 10.  Used as an overbag, the synthetic fabrics wick moisture from any down in the inside and bring it out.  This works in synergy with point #5 and #8 because if the down and shell of the down bag on the inside are warmer, this encourages/forces vapor and moisture to move outwards.  And in moving outwards, because of point #7 very little of this dampness will remain in the overbag, but even if there is a lot of dampness the fabrics will still provide good warmth.

Point #10 opens up a hotly contested debate in the backpacking community about what sleeping bags are best: down vs. synthetic.  I even contributed my own thoughts on the matter in a video in response to Craig of The Crawling Road blog/vlog (it seems like Craig has since closed his Youtube channel, unfortunately).

Not to repeat too much of what I said in the video, but one point that is at the center of this debate on insulation is that down can get soggy from absorbing vapor and/or water.  And if it gets soaked, it does little if anything to keep you warm and takes a quite a long time to dry out.  I recently washed my Zpacks 40 bag for the first time since I bought it in 2013, and was reminded of just how difficult it can be to dry out an entirely soaked through down bag, as it took about 3 days to get fully dry.  And this is after gently wringing it out, putting it in the dryer on low heat for a few cycles, hanging it up on the sun, and even gently blow drying a few spots that needed extra attention.

And as I said in the video, I have never in all the years that I have been using down bags (or jackets/vests) have I had a bag get soaked or even wet enough so that I was too cold to sleep.  Sure my down bags have gotten a bit soggy, but nothing a bit of airing them out and putting them in the sun in the morning while I eat breakfast and break camp didn't fix.  On days when it was raining steady and there was no good opportunity to air them out in the sun, I would make camp a bit earlier so that I could air them out in the evening before going to bed.  Or you can stop at a trail shelter or trail town/village and air out down gear under solid shelter.  I've even used hand dryers inside of bathrooms of cafés and restaurants to dry off clothing and gear.

But let's take a moment to acknowledge how rare all this is in most terrains, because the majority of the days each year are not rainy in most places.  Unless of course you live in certain places that are exceptions like parts of Scotland and the Pacific North West of the USA, in which case then yeah, maybe you ought to consider going with a synth bag.

Anyhow, having a lightweight synthetic overbag for a down bag may be a good solution for soggy/damp bag issues.  And the extra weight could actually end up being less than other gear that the overbag could potentially replace under certain circumstances.  For instance in the winter when it's really cold I'll take additional sleep clothing layers.  I could leave some of them at home, plus enjoy a drier/warmer sleep system.  

But hey, don't just take my word for it.  For their recent (and first known ever) winter PCT thru-hike, Trauma and Pepper used a synthetic quilt as an overbag for their down sleeping bags for both additional warmth plus (and perhaps just as importantly) a way to keep their down bags/clothing drier.  They mention this in several interviews, such as this one for Gear Junkie:

"We used this synthetic quilt as an over-bag for our sleep system, with a down sleeping bag on the inside. In the winter you constantly need to dry gear. This combination helped make our sleep system versatile and prevent the down bag from accumulating condensation. In the winter because of the temperature differences, water vapor will typically condense somewhere inside your sleeping bag. This system kept our down bags lofty and dry and prevented us from losing performance and getting cold. "

One final thought about the warmth bump.  Let me tell you, I could really feel a difference in warmth crawling into my 20 bag inside of the overbag.  I've tested out my 20 bag on its own here inside my home several times, but laying inside of it with the overbag was like having my body teleported to a sunny tropical beach.  Quite warm indeed.  I'm looking forward to next winter when I can test this system out, be warmer, and hopefully have a less soggy down bag too.

How I intend on using Saco Verde will be obviously as a stand alone summer bag, but I don't plan to take it with me all the time and for ever trip during other parts of the year.  When low temps are predicted that extend around or just beyond the limit of my 40 bag (which for me is roughly -2C / 28F), then I can take the overbag.  On more involved trips (e.g. an off trail trip, extended section hike, or thru-hike) in colder conditions then I would take both my 20 bag plus the overbag.  And of course for very cold, shorter trips of any sort I'd take both plus more clothing as needed.

Well, hopefully this little project will be of some use to others.  Really looking forward to putting my Saco Verde to good use, and soon.

Update continued:

I learned a lot about my new project on a 4 day section hike.  Overall it worked out great!  It was the perfect conditions to test out the Saco Verde/Zpacks 40 bag combo, with lows hovering around -2C/28F for all three nights I was out.  

The 1st night I was toasty warm and slept well in a run down shack.  The 2nd night I slept in my tent in a clearing, and woke up a bit chilled in the middle of the night due to cold winds sapping out warmth.  But after a few minor adjustments of bundling up I was able to go back to sleep and felt well rested the next day.  The 3rd night out sleeping in a good trail shelter in the woods I slept warm and well, but decided to try a little experiment.  This night I slept with Saco Verde on the inside rather than the outside just to see what the difference would be.  

I felt slightly warmer, however when I woke up and separated the bags, there was a fair amount of condensation on the foot box of both bags.  After airing them out while I ate breakfast and broke camp they were dry again, though.  As expected, on the 1st and 2nd nights there was no condensation and the down bag was fluffier and drier than usual--just some very minor dampness on the outside of the tip of the foot box, and that was only after the 2nd colder night in the clearing.

The fit of the bags together was fine, however because I move around somewhat in my sleep, I noticed a small shortcoming of the design.  The insulation is only on the top, but moving around in my sleep caused the Saco Verde to shift around some.  This is a minor issue really, but it did shift the bag so that part of the insulation moved to one side a bit, off-centered.  But because I am pretty nitpicky with my gear, I thought that in the future I would want to have the insulation go further around the bag and take a minor weight penalty.

This also got me to reconsider using Saco Verde with my Zpacks 20 bag--if it was tight at home without me moving around much, it would be pretty annoying late at night in the cold having to deal with the tight fit.  Plus this would also squish the down in the top of the bag, which in the end might make it less efficient because the loft is what makes down so warm.

*Additional update 24/07/2015:  I eventually found a great solution to my sleeping bag conundrum, which is the SOL Escape Lite bivy.  I wrote an updated breakdown of all of my sleep systems, which you can check out here, that features both El Saco Verde and the SOL bivy and how I will use them.

No comments:

Post a Comment