Backpackable Wood Stoves: Theory and Ultralight Application

[Stephanie Jordan]

Companion forum thread to:

Backpackable Wood Stoves: Theory and Ultralight Application

[spelt with a t]

In before, "this is diluting the purpose of the site" and, "this is BACKPACKING light, not sit-in-a-(warm)-tent light!"

[William M]

If not looking for something to heat with, if looking for a cooking stove, look at the bush buddy or the stainless knockoff, solo stove.

[Spyros Fykas]

Interesting article, but not exactly related to lightweight backpacking. I imagine that the more people and the bigger the tent the better, as you can split the weight of the wood stove in many backpacks.

[Richard Nisley]

Dave,

I recently spent a very cold winter month, in the bush, experimenting with ways to deal with sustained sub-zero temps. I started to do the same research covered in this article. So, I have a STRONG appreciation for the experience and effort that went into publishing this information. Please keep up the good work!

[David Chenault]

Good call Spelt. [sigh]

Richard, much appreciated and will do.

[David Thomas]

I haven't taken this plunge (in-tent wood stove) yet, but I can imagine it in my future. I've seen enough great-white-hunter gear with canvas wall tents heated with a cast-iron or heavy-gauge steel sheet metal stove to appreciate the utility of extending the BPing season. When there's only 5.5 hours of daylight, maybe 9 of useable light, you spend A LOT of time in your tent.

So thank for the article, DavidC. The Big Sibling seems most appealing to me, although I'd be sorely tempted to MYOG an adapter in the flue that could be capped most of time but have a SS water bottle inserted for snow melting and water boiling. Unlike pots on top of a wood stove (two imperfectly flat metal surfaces don't exchange heat very well), a pot INSIDE the flue would have high-velocity, very hot gases going by).

Not wanting all those Heat Exchange classes I took go to waste, I have to comment on, "Thin stainless steel is pretty good at transferring heat fast, and titanium sheet and foil even more so." which is a common misconception. Sure, thin metal transfers heat marginally faster than thick metal, but the vastly larger resistance to heat flow is from the boundary layer of air on each side, especially on the outside (the inside has greater air velocity plus there's lots of radiant heat transfer happening. So consider the thinness of the metal as it relates to weight and durability (and possibly heat retention at much greater weights), but not as a factor in heat exchange. That sentence could be replaced with "All of these stoves get their small surface areas to a high temperature while being fed with dry wood." to segue to your point (feed it frequently for heat, don't expect all-night output) in that paragraph.

The other phrase that gave me pause was, "Since none of these stoves are air-tight, mild smoke scent within the shelter and on your gear and person is inevitable." which is true, but a more major factor is lack of adequate draft because of the short stacks. It is a truism in wood stove installations (I used to work at a solar / wood stove installation company) that "a chimney can be too short, too narrow or too wide, but never too tall". Adequate draft ensures a negative pressure at all points in the firebox and along the stack so any gaps or pinholes leak IN, not OUT. If you get a hankering to experiment some more – maybe when you're close to home or the car – bring along a few extra lengths of stack (it could be any galvanized or even aluminum (if you put it on top) duct of the correct size from Home Depot). You'll likely find the smoke smell is greatly reduced and that the fire is even more self-stoking. And, as you correctly note elsewhere, a longer stack will minimize hot sparks landing on your tent – they will be more completely burned when they exit, they will have further to fall through cool air to the tent and may well be blown away entirely.

Alas, the cold, wet, windy place I've been backpacking the most recently – Adak Island in the Aleutians – doesn't have any trees, or I would have gotten a stove and stove jack for my Megamid long ago.

[David Thomas]

"not exactly related to lightweight backpacking"

Perhaps it is not related to the lightweight backpacking YOU do, but it very much related to some ULBPing I wish to do. Case in point: BPL's Erin Mckittrick hiked / packrafted 800 human-powered miles past my house and on to much more remote, wilderness regions with (and I'm going to capitalize this for emphasis) A 2-YEAR-OLD AND A 4-YEAR-OLD! Two adults carrying gear, clothing, food for four plus 27 pounds of toddler for a week+ of land and water travel at a time, week after week for 3 months. Obviously, they had to use lots of UL techniques and gear, which included a wood stove in their tent. While circumnavigating Kachemak Bay, they got hammered with 30-40 mph winds and 20F temps plus some snow for a few days. Without a place to warm up and dry out clothing, that kind of trip wouldn't have been tenable. They sent the wood stove home from my house, but regretted that a bit 10 days later when wind and snow returned one last time prior to summer really arriving.

UL, like the speed of light, is all relative. My base weight in the winter in Alaska is rather more than my base weight in the summer in California.

HYOH. Burn your own wood. Or not.

[Karl Kerschner]

IMO that this article is consistent with UL Backpacking, certainly with backpacking-light.

UL Backpacking is viewed by many as a philosophy and method set that includes the use of modern, often high tech devices that can be carried effectively for what are often long distances during a given day and days. This is in contrast to spending hours making shelters, fire backlogs/backstops, etc. The UL devices are usually chosen based on the route's situations, terrain, and conditions of the environment traversed; on the size of the group, as well as the purpose, goals and preferences of those participating.

One choice of gear is the backpackable wood stove, an alternative that is becoming more feasable.

Why not be open to all reasonable, effective possibilities?

[Ed Tyanich]

Ti-Goat actually had the first titanium cylinder stove on the market

[David Gardner]

I make ultralight saws for cutting wood to the proper dimensions.

http://www.GOLDGear.co

Nothing to assemble, no parts to lose, virtually indestructible.

For the sake of comparison, a folding Gerber with 5.25" blade weighs 3.1 oz, a folding Coast with 5.5" blade weighs 4.2 oz, Ed Biermann's Little Buck (http://www.qiwiz.net/saws.html) buck saw with a 15" blade weighs 5.4 oz with padded handle and sheath (4.9 oz without the padded handle), and a Bahco Laplander folding saw with 9" blade weighs 7 oz.

Modified Japanese nokogiri pull saw with 8" blade that will also cut bone, weighs 1.9 oz including sheath and tooth guard.

Modified pruning saw with 10.5 blade weighs 3.1 oz, including sheath and tooth guard.

Modified pruning saw with 15.5" blade weighs 4.6 oz, including sheath.

[Steve M]

Yikes–another comment by David Thomas that I'm agreeing with.

I've put this newer model wood stove (Titanium Goat) on my wish list:

http://www.youtube.com/watch?v=S43YCK3b_4g

…can't really justify it yet but might try to build one.

As always, HYOH

[David Chenault]

I stand corrected, Ed and David.

Regarding the issue of smoke in the tent with the Big Sibling; when the stove is running well the draft does pull in through all the various holes and gaps. You'll get smoke leakage when getting the fire started, as well as when you get lazy and have to stoke it back up. A taller pipe than strictly necessary does seem to help things draft better, in spite of seeming like a good place to save weight.

[peter vacco]

i am a bushbuddy sort of fellow, but for coming home late to a tent on a nasty wet afternoon, i often carry a can of sterno.
it takes not a ton of heat to make a closed tent feel better, and sterno is just the ticket. fast, easy to light, cheap, doesn't leak too much. it's all good.

so, that's my spin on tent heat. unless it's really a terrible cold place, sterno.

cheers,
v.

[Tad Englund]

Dave, another excellent article.

I have been entertaining this subject for some time now but as yet I haven't taken the plunge. This article gives me more to think about.

One thing that I keep coming back to is the issue of high heat and UL fabrics. Not with the shelter, but all the stuff inside. I guess my question is how do you keep from melting the side of a sleeping bag or jacket by inadvertently rolling over or sticking out an arm, allowing it to touch the side of the stove or stove pipe.
I am not uncoordinated or stupid but I'm human and when it’s late, I have overexerted myself or especially if I wake up in the middle of the night and need to relieve myself, it takes a few nanoseconds to get my bearings. My body is working on muscle memory and my mind is taking a little extra time to catch up.
In the picture below I noticed just how close the sleeping bag is to the stove (see the red circle). Now maybe this isn’t a problem and I am concerned about something that really isn’t an issue; but I would hate to melt the side of a very expensive sleeping bag because of a momentary lapse in physical location awareness.
I do wish your article could have covered this and issues like it. Namely “How do you use a wood stove in your shelter”. I do apologize if this has already been planned for a follow up article. I’m not knocking the article in anyway this is just a question I’ve been meaning to ask for a while.

[David Chenault]

It's a perfectly fair question Tad. Unfortunately the answer ends up being akin to "how do you not drive into the ditch on the way home?" Well, you just don't.

With little stoves like the ones discussed here the issue is a bit simpler because the window of high heat, where you could get (for instance) significant sleeping bag meltage in an instant is pretty small. The stoves aren't going to hold that kind of heat long enough for you to doze off and then get up in a haze to take a whiz. Probably more of an issue with big guns like the Kifaru Arctic and Seek Outside XXL.

Stove placement should predispose you to not be runnin into the thing all the time, and I didn't elaborate on this because covering all possible shelter permutations would take ages, and because I only have experience with the two shelters pictured in the article. With the Megalight, putting the stove on the non-door side of the pole leaves loads of space for each person, both to organize stuff and get in and out of their bag. With the Seek Outside LBO shelter (review likely out in late March), the stove is far to the front, but the LBO is wider in the back than the front, and has two doors, so again hitting the stove is made less likely.

In the end the possibility of burning your self or gear exists, but a few fairly simple things make it pretty unlikely.

[Jerry Adams]

Nice article as usual.

I too saw that picture and it seemed like you're asking for trouble with nylon so close to wood stove.

Maybe a little bigger tent would make sense. A wood stove will put out a lot of heat so it will keep larger tent warm.

[Kevin @ Seek Outside]

Dave should actually take some credit for the Big Sibling. I had worked on building the lightest stove I could on and off for a couple of years. I had tested various versions and found it particularly useful when weight and pack size was the primary determining factor of" if a stove was carried". In my usage, sometimes the benefit of having quick heat vastly outweighed the weight penalty. I was on the fence of ever offering it as a product, but Dave C seemed to have an interest so it became more than just a personal experiment in how light. At one time there was another damper that allowed for cooking on it as well.

That being said, we have continually tried to balance comfort , ease of use, and weight penalty. The larger stoves (including a new one coming soon) can burn pretty well, and pretty long, although they still won't get you through the night on heat they can provide usable heat for a lot longer. In cases where there are groups, if you dedicate yourself to cooking on the stove, the weight penalty can be offset pretty quickly. For times when I am out more than 3 or 4 days, with a group of 3 or 4, the stove is lighter than most cooking fuel.

[JP]

–

[Jim Colten]

"this is BACKPACKING light, not sit-in-a-(warm)-tent light!"

David said it better but perhaps I can say it shorter. The above statement is true only if backpacking light means staying cooped up at home whenever the weather is less than ideal or bailing whenever a cloud dares show it's face.

"this is diluting the purpose of the site"
think of it not as diluting, but expanding … getting out with the lightest kit suitable for the conditions … substituting skill for gear wherever possible.

[Anonymous]

Nice article Dave, appreciate the insights, testing, etc.

Unfortunately, or fortunately, depending on who you talk to, i don't live in a more extremely cold climate like yourself, but i've been loving these recent "polar vortexes"!

Anyways, i recently acquired a used MLD Solomid, of which i'm planning on making some mods to to winterize it.

Adding silnylon sod skirts to the back and part of the front of the tent (the sides don't really need it). Taping a IR reflective liner to most of the inside. I'm going to do it in a manner that there will be a bit of an air gap between the cuben and IR liner material (not using mylar space blankets, too weak).

Then bring a couple of smallish beeswax candles. I figure with all the above, should get the temps at least 10 to 15 degrees warmer than would typically be otherwise. Probably not enough warmth and heat to dry things out significantly faster like a real stove ala your article, but worth trying out i think since i don't have to chop any wood and save on battery usage too. All at very little extra weight or work.

Candles also look really, really cool under than IR shiny reflective surface too.

Anyways, keep on trucking and writing interesting articles despite the nags of the naysayers.

[Adam Kilpatrick]

I've not yet camped in conditions where I'd personally consider putting a stove in my tent for heat warranted, but if you are spending the time and effort and weight on a wood stove and the associated maintenance to keep it going, there might be a point where you are better off considering going down the inner tent route. I guess the way I think about it, is to relate to modern eco-friendly housing principles. If it is cold outside, you don't put a heater on inside, you build the skin of the house with decent insulation to begin with. Its very possible (and not hard) to build a house anywhere with enough insulation that body heat of the people inside will be more than enough to keep it at normal room temperature.

With a tent this is of course much harder, but you are probably carrying a decent sleeping bag anyway (unless you are burning half a ton of wood and running it all night long…) as well as warm clothing, so the differential between the desired room temperature inside your tent and the outside temp can be much greater than a house.

Would it be better or more efficient in really low outside temperatures, to instead design a better insulated tent? Thoughts include;

.3oz cuben side skirts to keep out drafts (doesn't matter if they get punctured)

Adding a third, or even fourth inner skin to the tent to trap more heat. They could be partial

Adding partial or whole reflective skins to the inside of the tent aka a space blanket, or something like the technology inside a thermarest neo-air.

If I was taking my young kids along (currently have 10month old girl, but will have another) on a really cold trip, I'd definitely have the clothes and bags for them anyway, and they'd constantly be bundled up. Its not that hard to do (in my experience so far in the snow and rain of Japan with Hannah), and I think I'd find the economy of actions much easier to just keep them warm with an otherwise warm tent and clothes than trying to keep everyone safe in a tent with a woodstove and multiple toddlers.

HYOH of course, this is just a thought. I definitely see the woodstove in tent thing as AWESOMELY romantic…maybe the wife will see that too and let me kit us up with this caboodle :-)

[David Chenault]

Josh, I've never had an issue, except (ahem) that one time I shoved the pole tip through the sil instead.

[Jerry Adams]

what do you use for IR liner material that's not mylar space blanket which is too weak?

[Greg Mihalik]

Josh – "do you ever notice any damage at the top of your tent from having it supported by the trekking pole carbide tip?"

My DuoMid had a "receiver cone" made of a very heavy duty fabric. Nothing would damage it.

I assume most are made that way.

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