Do it. Make One.
I did and it worked smashingly.
And I definitely have the best looking sleeping bag of anyone I know.
Who do you know with a striped worsted wool mummy bag? Make one of your own and get the envy of your camping buddies.
McChoppinites, I’ve returned! To talk once more talk about my hero Shackleton.
One of the perks of working in a research environment is I get to hear about other people’s interesting research, and, way before it’s on NPR. Today I got to hear about Dr. Stephen Rock’s, a professor from Stanford’s Aeronautics & Astronautics Department. He came to tell us about robotic submersibles, which is totally awesome. Sure underwater robots are very topical right now, but he actually wasn’t there to talk about turning off the well head of Deepwater Horizon. He was there to talk about icebergs!
As it turns out, the place to go to find icebergs is the Antarctic, of course. Specifically the Weddell Sea. What else is in the Weddell Sea? Oh right, Elephant Island! That’s right, Shackleton!
Dr. Rock is interested in developing technology that would autonomous map an iceberg to allow an unmanned craft to collect ocean samples at specific points relative to said iceberg. Interesting stuff to me, but I realize it might not be exactly McChoppin’ material. But that’s not what I want to talk about. See, Dr. Rock was doing a technology demonstration for a future program that is driven by the needs of oceanographers and marine biologists that want to study the ecology of the sea around an iceberg. More importantly, he was doing this work on an icebreaker in the Weddell sea with a bunch of biologists who actively study icebergs. So while he was gathering this data for the proof of concept, they were studying the icebergs. One of the things that the biologists are concerned about is better tracking of the icebergs. See, they wanted to put a GPS device on the iceberg. But the ship can only get so close to the iceberg; icebergs being dangerous and all.1 So how do you you get a GPS transponder onto an iceberg? Well, their idea was to shoot it onto the iceberg. But not with a gun or cannon. Their idea was to shoot it on with a water balloon-style launcher. Being that are good scientists and wanting to test their device first, they decided on a test shot. What did they test it with? A coconut, of course.
I think the only question left unanswered here is: what is the airspeed velocity of an unladen Antarctic Swallow?
(photo badly Gimpped together from egvvnd and tim ellis)
1 For anyone who doesn’t know about icebergs we are talking about an iceberg 40 km long and 20 km wide… dangerous? yes!
I had previously promised that I would write a post about the winter campout after I got photos from it developed. Just before going back East for the holidays I had discovered this laying about.
Well, I had not used a film camera in a long time and I had never used a manual camera ever, but I did not let that deter me. I got some film and read a bit about it; I figured I was all set and at least some of the pictures would come out okay. So I took the damn thing camping. Unfortunately, I failed to learn how to properly load the film. So not a single photo was taken. I guess I am not Frank Hurley.
Since that time I have learned how to load the film properly. I am happy to report that the camera is fully functional and despite with my total lack of photography skill it takes rather good pictures. So, I am excited about using it a bit more, you know, learn a few things about film speed, aperture, and what not. Eventually I would like to get a good digital camera. I’m rather excited to find out that camera companies are making models that are not quite SLR’s1 or point-and-shoots. It sounds like the candidate name for these cameras are Interchangeable Lens Compacts. I really like the one by Olympus, the PEN EP-1, but that will probably have to wait. In the meanwhile I’ll continue to cut my teeth on the Pentax. The thing is a beast and besides its old-timey appeal, it will be able to take the abuse of winter camping better than any digital camera will, I suspect.
1Not only do digital SLR’s look ridiculous, it is an awkward marriage of old manual camera technology with the new digital. I’m sure people out there will argue a bit, but I can not see any reason to have a reflex mirror lens system in a digital camera. I’m actually surprised it has taken the camera industry this long to realize that people would want camera system that essentially acts like an old manual SLR without looking like, or even being, one.
How many times have you come back from winter camping and in the process of relating your story been forced to say things like “Well, it was cold. It was 10 degrees in the valley, so I’m sure it was below zero up on the mountaintop, where we were.” It is not so satisfying, is it? Wouldn’t you like something a little more exact? But, considering the demands of the winter campout, you don’t exactly want to bring a mercury-type thermometer and have to write down the temperature at intervals. Especially when the most interesting time to take the temperature is probably in the middle of the night, when you have much more important things to do, like stay in your sleeping bag.
Well, even if you have never been troubled by this problem, I have been. After this past winter’s campout, I was pretty disappointed that the best I could do for the answer to the “How cold was it?” question was say: “Well, my dad said it was 2 degrees outside his house down in the valley when he woke up.” I wanted to know exactly how cold was it overnight where we where. I think it was colder, but how do I know? Also, I only had one temperature point to go off of: 2 degrees. What about the rest of the time? We were out there for two days. From my days of undergraduate physics I know that dataloggers exist and I suspected that there existed one that would meet my needs, which was a simple device that would automatically record the temperature at intervals and save it to later be downloaded to a computer. I recently found one such device: the Lascar EL USB-2. Indeed I think that it meets and exceeds all of the requirements that I could come up with.
The Lascar Easy Logger USB 2 is a small digital datalogger that records not only temperature, but also, as a bonus, relative humidity.1 The temperature range that it covers is from -31 to 176 degrees Fahrenheit, which is the range I would normally expect to encounter whilst camping. It is waterproof and has a very compact, minimal design with no buttons, so it should be durable enough to withstand the trials of winter camping. It has a long battery life of one year and it can store 16,382 measurements. At measurement intervals of one minute this means it will record for almost eleven and a half days. It is operated entirely through a computer interface which is very straight forward. There, one can set the measurement interval (every 10 seconds up to a half day intervals at specific intervals), the time when it will start (immediately or some preset time), and various alarms (like high or low temperature alarms; I don’t yet think I have much use for this functionality). So, basically you plug the thing into your computer’s USB port, do a quick setup, and go off recording. When you are done, you plug it back in and it the software will display a nice graph. I took it to Tahoe with me over the weekend.
You can click on the image to enlarge it. I annotated a few major portions of the graph. The first night I left the datalogger outside in my truck. The temperature in the truck seems to have steadily declined until reaching an “overnight” low, which occurred some time around 8 o’clock in the morning and was 34 degrees. The second night I had it inside our cabin. Again the low occurred at 8 in the morning and it was 58 degrees. My girlfriend had decided it was necessary to use a number of blankets whose combined loft easily exceeded the sleeping bag I used during winter camping. At some point in the middle of the second night I woke up rather overheated and threw off almost all of them. I can clearly point to the graph and show her now that since it was above 60 degrees Fahrenheit in the cabin we clearly did not need so much covering. Such are the dangers of winter cabining, I suppose.
1 Lascar has a model, the EL USB-1, which takes only temperature but is otherwise the same. It is cheaper, but I thought having relative humidity might be interesting. One could investigate the effects of humidity on your camping experience, but that is probably subjective at best. Temperature is probably the most interesting feature for logging camping conditions and so if one is more concerned about the cost than I was, I recommend the EL-1 for providing your camping datalogging needs.
I just recently finished making my own sleeping bag. So, let’s say you are like me and you want one as well. One of the initial things that you will want to do is gather your materials. Although it’s a lot more interesting picking out the fabric to use for the shell, the major material in terms of amount and cost is the insulation. Since you are building your own sleeping bag I am just going to assume that you will be using down feathers as your choice of insulation. I can not actually imagine why anyone would go through the trouble of making their own sleeping bag if they plan on using polyester filling as insulation. If you are that type of person, I suggest you just go purchase one of the ubiquitous synthetic material bags on the market. If you still want to do this, you might as well read this post as well, since it will at least give you some idea of what you need to think about for how much insulation.
The function of the sleeping bag is to provide long path of low thermal conductivity material between you, the thing being insulated, and the outside, the thing that acts as a heat sink. The way it does this is by trapping a large amount of air and changing the mode of heat transfer from convection to conduction. Air is a good thermal conductor when it is free to transfer heat via convection and a very good insulator when it is limited to only conduction. This is why sleeping bags can be so light; you are utilizing the air surrounding you as a thermal insulator by limiting it’s mobility. Down, it turns out, is very good at limiting convection in air without adding much additional weight. It also has the very desirable quality of being a resilient material that resists permanent deformations. These two qualities together make it ideal for outdoor activities. And of importance to the McChoppin’ mindset, it’s an old-timey material. You know, something that Shackleton himself could have used. 1
In the sleeping bag business world the lowest temperature that can comfortably be tolerated in the sleeping bag is normal equated to “loft.” Loft is the path distance between you and the outside, or, in other words, the thickness of the sleeping bag from the inside to the outside. The total thickness of the bag should be twice its loft. However, in determining things for making your sleeping bag, in particular, how much down feathers to purchase, we care more about equating the temperature to the weight of the down that we will need.
It turns out not all down is equal. It’s actually all equal from thermal conductivity stand point; down as a fill insulation is mostly air and therefore has essentially has the thermal insulation properties of air. The major difference in down from batch to batch is the density. The inverse of down’s density is expressed by down feather merchants as “fill power.” Because it is the inverse, a higher fill power is a lower density. Numerically, fill power is equal to the number of cubic inches 1 ounce of down occupies. I imagine they choose inverse density as the metric because, for the purpose of purchasing things, larger number means better to most people and therefore they can sell 900 fill power down for more than 700 fill power because most people would rather have less dense down.
The fill power rating for most down sleeping bags seem to range from about 650 to 900 fill power.2 As I said the only major difference is density. And since I’m not particularly concerned about the weight of my bag, I’m not terribly concerned about the fill power, other than cost. However, there does not seem to be much of a market out there for down feathers that is readily accessible directly to the individual sleeping bag maker. During my search I found my self pretty much limited to the 900 fill power end. And keep in mind that you pay for down by the ounce, but how much you need is dependent on the type of down you buy. Therefore the ratio of the fill power directly relates to the ratio of the price in down. In other words, let’s say that you find 900 fill power down that sells for 30 dukes for 3 ounces. You also find 700 fill power down that sells for 25 dukes. If you don’t care about the weight, which down should you purchase to reduce your cost? It turns out that you should go with the more expensive 900 fill power down.3 The 700 fill power down should be less than $23.33 if it is going to be more economical, assuming everything else is equal.
Alright, I’m going to assume that your pricing of the market is going to lead you to the same conclusion that it lead me to: 900 fill power down.4 So, how much do we need?
Well, I’ve gone through the little bit of trouble to get this equation that relates expected outside temperature to amount of down needed. It is , where T is the temperature in degree Fahrenheit you plan on taking you bag to in the outdoors and W is the weight of 900 fill down you will need in ounces to achieve this. A few thing recognize immediately is that at zero degrees you need 19 ounces of down. For every degree above that you need one third of an ounce less. For every degree below that you need one third of an ounce more. This equation also says that you need no down in your sleeping bag if you plan on going no colder than 60 degree Fahrenheit. That seem reasonable, as at 60 degree I can sleep clothed with little more than a light blanket.
So, that is pretty much all you need to know. Pick a temperature, plug it in, and that is now much 900 fill power down you need to buy to start making a sleeping bag. Go nuts. But there are a few more things you might like to know about the equation and what went into it.
First, if you don’t get 900 fill power down you can still use the equation. Just calculate the amount of down you would need if you were getting 900 fill down and multiple it by the ratio of the fill powers. So, if you needed 22 ounces of 900 fill down you will need 28 ounces of 700 fill power down.
Second, I made this calculation based upon my size: six feet four inches. If you are a lot different in size, than you will need more or less down. By “a lot” I mean that for this rough calculation, anyone less than 4 inches less than me in height will need at least 5% less down. A similar thing for your girth: I’m fairly skinny.
Also, keep in mind this is a rough calculation. The exact amount of down you will need is related to how much space you need to fill in your sleeping bag. Due to difference is construction and actual down quality you may end up needing a little more or a little less.
All right, all those caveats aside, you’re probably wondering where I got that equation from: using freely available data of the intertubes I did a linear fit to all the data points and got the equation. How good is the linear fit? What was the data?

The data I gathered from Peter Hutchinson Designs, Feather Friends,Western Mountaineering, and Thru-Hiker. The PHD results are easy: they already give 900 fill power down in terms of weight needed for a specific temperature. For TH, they give you a loft for a desired temperature. So I just calculated the total volume given the loft and my dimensions and divided by the fill power. Because WD and FF don’t give much information about the down that they use, I had to assume a fill power and correct for it to get everything into 900 fill power. Despite the fact that both WD and FF seem to hint at using a higher fill power, an assumed fill power of 750 seem to get the data inline with the PHD and TH results. FF and WM still seem to be pretty conservative with the temperature. But they all agree that no matter which down you choose you don’t need any at about 60 degrees Fahrenheit. Personally, I choose to more heavily weight the PHD and TH results for a couple of reasons. First, they were the first two data sets I looked at: blatant human bias. Second, they both went for a more conservative approach with the amount of down needed: I wanted to buy less down. And finally, I suspect I will need less down then the market that FF and WM are going after: total hubris. So, keep in mind that my equation is likely to be on the absolute low end of the amount of down that you’ll need. I don’t recommend getting less than it tell you. If you think you might be want a little extra thermal protection, get more down.
All right, so I was going to talk about how well this simple model for projecting the amount of down you need compares to an actual (but still relatively simple) thermal model of you, the sleeping bag, and the outdoors, but this post is too long already. For example, my equation predicts a number for sleeping in outer space. Which, for the sake of this discussion, is 0 Kelvin.5 Or -460 degrees Fahrenheit. It tells you you need some 170 ounces of 900 fill power down. At 30 dollar for 3 ounces, that equates to a cost of 1645 dukes. Down is by far the highest cost involved in a home-made sleeping bag, so we can use that as an estimate for the total cost of the bag. Western Mountaineering’s best bag only goes to -40 degrees F, but costs half as much! By the way, it turns out that that much down (170 ounces) would offer 3 feet of loft. I’d be in a sleeping bag that had a diameter as much as I am tall. But would that really work? I suspect not. But we will check it out in a future post.
1 Shackleton, if my memory serves me correctly, actually used sleeping bags stuffed with Reindeer fur. An intriguing idea, one that I’d be tempted to try, if it weren’t for the fact that during their 800 mile open-ocean voyage to South Georgia the bags got wet and started to rot. Shackleton and this men later complained that everything was covered in hair and that it often found its way into their mouths. It does not sound like a pleasant experience.
2 I will ignore the “+” part of the description of down because I feel that it is even more of a marketing ploy; if 650+ down was really significantly different than 650 fill power, why not just label it 700?
3 Unless you want a sleeping bag that needs less than 3 ounces of down insulation at 900 fill power. But I’m imagining that you aren’t planning on making sleeping bags for for pet canary, in the quantities that you will likely need we can ignore the fact that the economics depend slightly on much down you are getting.
4 Unfortunately there just doesn’t seem to be a whole lot of other reputable options. If you can find any I would be interested to know of them.
5 Also, nevermind that the major component of heat loss in outer-space is is radiative heat loss and not convection and conduction, which is what your sleeping bag can protect you against. If you want, you can imagine that your in an air filled bubble at standard pressure floating around in outer-space and you need a sleeping bag to keep warm. And please don’t bring up any other objections, after all I am a physicist.
Happy New Year everyone. Hopefully you too are enjoying a lazy New Year’s day with good food and drink.
And in case you haven’t heard, the winter campout was wildly successful. I’m currently awaiting pictures that need to be developed,1 but after I get them I’ll cover the winter campout of 2009.
1 Because taking photographs with a film camera is a lot more old-timey. That, and I doubt a digital camera would survive the winter campout.
The forces are assemblying and converging on the VT. The Slickman is arriving by land, I am coming by air, and word has it that Dan the Man may be coming by way of the sea. It’s blitzkrieg on the Northeast, McChoppin’ style.
I’m currently in a staging area south of the theater of operations awaiting resupply before the final push. Whilst I was in route I met a comrade, a friend of old timey ways. A fellow who, not only goes camping, but, does so with a wool blanket. I know you’re out there, fellow McChoppin souls. It gives hope to our cause.
Phase two of the plan is set to commence in the morning hours of Sunday. Operation Old-Timey Freedom: a Coalition of the Woolen ride out north with the stated goals of succesful winter camping and the establishment of old timey pratices as a role model for camping. It is to be a two day operation involving handmade goods, spot-built shelters, and an assortment of salted meats. Early intel suggests favorable conditions for operations that should minimize casualties.
In the spirit of Shackleton we go.
I finished my sleeping bag. Just in time for the impending winter campout. It looks awesome. And it has slightly more loft then my synthetic fiber sleeping bag from EMS. Surprisingly though, it weighs the same or maybe a little less.1 This is surprising because I choose to make the outer shell out of wool fabric as opposed to nylon. Part of wool’s old-timeyness is that it weighs quite a bit more than nylon. I suspect that all the weight saving came from using down as opposed to polyester as the fill material.
In the coming posts I plan on going in depth into how to make your own sleeping bag, or at least how I made mine. I also plan on looking at how sleeping bags work as a thermal insulation device to keep warm with the express attempt at evaluating the performance of different materials. And finally, I plan on discussing this year’s and past year’s annual winter campouts.
In the mean time, happy holidays. My work year is over and tonight I take a red eye back east. Although the NOAA local weather forecast shows some rain during the winter campout weekend, it looks like they’re predicting no rain for the days that we are planning on going. The only thing I want for the holidays is to break the three year streak of a dank winter campout. Well, that and a lot of egg nog.
1 I do not have a sensitive enough scale to weigh the bags accurately. However, the weight difference either way is probably 2 ounces at the most, which, to me is inconsequential.
Owing to the fact that I grew up with three sisters, the closest thing I have to a brother is the Slickman. However, the closest thing the Slickman has to a brother is Dan the Man, his actual brother. Dan the Man is quite the character and adds quite of bit of color to the Slickman and mine’s already rather colorful stories. One for the ages is what I like to call: “Scrimshaw Shackleton or: How I learned how to ‘Pull a Shackleton’.” As previously mentioned, arctic exploration is a subject of particular fascination here at McChoppin’ and this story should go quite a ways in explaining why.
Dan the Man has always liked history. Especially the more McChoppin’-style history: you know, the man-vs-nature, frontiersman kind of history. I suppose the Slickman and I like our fair share of it as well, but Dan has always liked it with a bit more earnest. After all, he it was his major as an undergraduate.1 Anyways, a while back Dan the Man read Endurance.2 He was immediately taken in by the heroic tale of Shackleton and his crew. He was so taken in by the tale, that he actually started using this as a conversation piece at parties. This was not advised by the Slickman and I, but he continued to do it. It became his thing. He’d met some girl at a party and start talking about the epic tale of the Endurance. Sometimes it went well: “Oh man! Dan is pulling a Shackleton!” Most of the time it did not: “Oh no! Dan is pulling a Shackleton!” This behavior only became more acute when we discovered that a local brewery made an Endurance Pale Ale with the cheery face of Tom Crean plastered on the front of every bottle. I’ve always imagined that Dan the Man would make an excellent candidate for a Drunken History, but this really seems like a good fit. Seriously, I can see it now:
Late one night
Dan the Man drank eight Endurance beers
And then discussed this historical event…
Derek Waters presents
Drunk History“Tonight we are going to talk about Tom Crean…”
It cuts to Thomas Jane portraying Tom Crean and then goes on with Dan telling some obscure story of arguable authenticity. Mayhaps it involved a story from Tom Crean’s later years, when he owned a public house in Ireland. Mayhaps Tom helps show a young lady how to lit, I mean, light a fire. Even more likely, in the middle of the telling Dan pauses to offer his assistance in helping a young woman lit, i mean, light a fire. And eight beers is quite a lot for Dan the Man, so I can only imagine he is completely successful in his attempt.
Either way, this episode cemented the whole arctic exploration theme into the McChoppin’ psyche forever. There had been previously been flirting with it, to be sure. I had already read Apsley Cherry-Garrard’s account of the Terra Nova expedition. I had also read Ben Jones’3 novel The Rope Eater which dealt with arctic exploration as a major theme. And of course, arctic exploration naturally fit into our interests. The mild obsession with the arctic exploration theme continued with a scrimshaw Shackleton sighting and finally culminated in pipe carving. But that is a story for another time.
1 Castleton State College does not have a Bachelor of Arts degree in McChoppinesque History, but it should probably consider offering one.
2 I believe it was the Alfred Lansing book. I read Capt. Frank Worsley’s tale.
3 A random connection: after I read Ben Jones’ book I discovered that my sister knew him from Bennington College and had even occansionally watched his kids.
The sleeping bag is coming along, but very slowly. I keep getting distracted by a lot of things. Soap making. Fixing leaky faucets. Getting a Christmas tree and then making a wreath out of the excess boughs…. Yes, it is the Holiday season and this will make it particularly difficult to finish the sleeping bag in time for the annual winter campout. What, with the twelve drinking days of Christmas starting tomorrow and multiple holiday parties on the horizon it will be a struggle to get any sewing done, but I’m convinced it can be done.
So, speaking of holiday parties, the neighbors had two last night. One was directly across the hall and the other just around the corner. We just stopped in for a couple of drinks; we didn’t really know anyone, although we met some nice people. Mostly it was just good people watching. For the first party we brought a bottle of sparkling wine that was in the fridge, which turned out to be a huge hit. Before I had even delivered it to the hostess I had people asking me to open it. When it was finally opened, glasses appeared, ready to be filled. I’m not to sure of how the bottle ended up in our fridge to begin with, but it was wine from Carneros, the southern part of Napa and it was pretty good. Either way the people at the party definitely liked and it was gone quickly. At the other party they had a couple of bartenders and an assortment of bottles, punches, and other libations. When I asked the bartender if I could get a Manhattan, he answered “no, but you can make it yourself,” thrusting a cocktail shaker and a bottle of Hudson bourbon at me.1 “No worries,” I thought, “it’s probably better that I do it,” and I mixed up a couple of Manhattans, one for me and one for the miss, and gave a taste to the bartender. Tasting it, he nodded approvingly and we cheered.
But what I really want to talk about it the cocktail I made before going to either party, the one I made whilst getting ready. I had been sort of inspired a bit before Thanksgiving by Michael over at A Dash of Bitters on this post Raising a Glass in Thanks. I to wanted to make a holiday cocktail. What with the recent Christmas tree, wreath, and the impending holiday parties, I thought that now would be a great time to start experimenting on one. I wanted some that really captured the holidays in a glass. Something spicy, but also with a touch of sweetness. And I wanted to use some Carpano Antica vermouth2, which I had recently discovered about a month ago and have decided it is the best thing ever. I’m not actually a huge vermouth fan, but this stuff is one a whole other level. It is sort of like when I finally had good gin and was reborn a gin aficionado, only even better. Anyways, I was convinced that the Antica would do superbly in my holiday-themed cocktail. I looked over my assortment of other liquors trying to think of what else would round out the formula that I was requiring. As soon as I saw it, I immediately decided it would need some Nocino della Christina in it. Nocino is a walnut liqueur that I absolutely love. I figured it would add just the right amount of sweetness and the necessary depth of complexity to the cocktail that I was looking for. I then pick up the Calvados for the base liquor and, remembering an article I read by Gary Regan about Christina, I also grabbed my bottle of Regan’s orange bitters and some Creole Shrubb. Here is what I mixed up:
The Carpano is the only one that is that you specifically need to make this. It is a must. Nothing else will do. Do not even think of attempting to make this with Martini & Rossi vermouth. Other than that, I used Calvados Prestige from France, but I’m interested in trying this with a different brandy, possibly a Cognac, although the spicy-appleness of the calvados does impart something quite nice. I also imagine any nocino will do here, but the only one available to me is Christina. It’s local to me and very, very good, so I recommend it. The Clement could definitely be played around with. I am not an expert by any means on orange liqueurs, but I do like Clement and it is different. I’d like to try it with Prunier Liqueur d’Orange and I’m sure Grand Marnier could work, but probably not as well. There isn’t a lot of orange liqueur in there, so it probably doesn’t matter that much which one you choose; I limited it because I wanted to control the sweetness of the cocktail and just add a hint of orange as a highlight.
Once you have everything, combine all the ingredients in a mixing glass with ice and stir well. Strain into a chilled cocktail glass and garnish with orange zest. I think I’ll name the drink “Lit Up,” but you can call it whatever you want.
So, I thought it would be a process to develop this beverage. But I’m so pleased with my first attempt that I think it’s good enough as is. I might play around with it a little, but certainly the basic elements I wanted are all there. It’s spicy deliciousness. And very complex. Certainly a holiday beverage. Now I just have to figure out how I am going to get all the ingredients back with me to Vermont so I can enjoy the cocktail with family and friends on Christmas. But then I also have a sleeping bag to finish. Like I said, I keep getting distracted.
1 He may have also mumbled something about Hudson bourbon being the “best bourbon ever made” while he handed it to me. I can’t really argue with that.
2 Carpano vermouth was what I used to make the Manhattan at the do-it-yourself bar. In fact, the Carpano and the Hudson were the reasons I wanted a Manhattan at all.