5c Camping Stove (Penny Stove)

The making of an awesomely light weight and cheap camping stove that punches well above its weight. No compromise on cooking time, but a big saving on weight in your backpack for weekend trips. Uses cheap and easily available fuel such as Methylated Spirits, or pretty much any other high percentage alcohol / ethanol you can find.

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One of more my successful prototypes. Very clean burning and hot flame, well directed to the pot. Yes that is red hot steel you can see!

I started all this a few years ago, but thought of this recently when cleaning out my workshop as I’d kept a whole punch of a prototypes and raw materials. I really wanted to finish what I started before throwing anything out, so I dusted everything off and this post is the result. Oh, and as much as this is has zero woodworking involved, I did say “and other creations” so I figure this fits 🙂

Building, and experimenting with these stoves is a heap of fun and I learnt quite a lot in the process. I still don’t understand why more of my hiking friends never got into these things, but here’s my attempt to perhaps convince a few people. Yes the fuel these stoves use is a lot less energy dense, so you have to carry more, but the weight difference in the stove and related items more than compensates, making this an ultralight option for many weekend and longer trips.

How it works

A quick visual helps a lot when understanding these stoves, so I knocked up these schematics. While you can be successful blindly following a set of instructions, if you understand the fundamentals you can tweak your design here and there to suit your preferences.

Stove-PreheatingPhase
Pre-heating Phase
Stove-CookingPhase
Cooking phase

I won’t go into a full “how to” guide on this, but rather suggest you go download the relevant templates from http://www.zenstoves.net. I followed mostly one of there designs; with a few tweaks if my own.

The Build

After scavenging a number of empty aluminium drink cans from the work recycling bin (yes I got a few raised eyebrows) I then went to the trouble of polishing off the labels before I did anything else. Really this was just for asthetics as I liked the look of the raw aluminum in examples is seen, and it looked a bit less like something made out of rubbish… which of course it is, but I don’t want advertise it 🙂

The inner wall I used the zenstoves template to get the size right and locations for the notches to let the fuel pass into the outer chamber. It’s the inner wall that really sets the height of the stove, as you push the halves together over it to create a mostly sealed outer wall chamber. I used 20mm for the inner walls and around 30mm for the top and bottom halves. That seems to give ample volume for cooking a decent sized meal and hot drinks for two people, so you could go smaller for a solo stove.

To cut the parts out I used a cutting disk on my dremel, but a sharp knife works quite well too.

Stove4
The base half with the inner wall in place. There are small half holes in the inner wall to let the fuel enter.

This design uses two cans rather than just one, so after chopping both down I picked one as the top and punched the jet holes it. Size and number can be experimented with, as this affects efficiency, boil time, etc. But I found 32 holes, using an average size sewing needle (maybe about .8mm) to make the holes, worked quite well. Too much larger and you get so much fame that most of it is wasted heating up the air. Too small or few of them and it takes too long to heat up.

Stove1
The top half with 32 pin holes evenly spaced.

Next I cut out a filling hole (not pictured) in the middle of the top of the can. This should be large enough to be able to fill with fuel, but small enough to cover with a small coin (5c or 10c). About 10mm diameter was what I went with. I used a dremel to burr out the hole. But if you don’t have one you could use a drill, and or a file to open the hole up to the size you want.

One modification I made to the zen stove design was to drill some holes around about half way up and then just up to these points. This made it easier to assemble later. This still leaves enough overlap to form a nice seal.

Stove3
Top half with slits cut. The little holes help avoid it buckling when it gets inserted into the lower half.

Assembly was by far the trickiest bit. and unfortunately if you stuff it up you end up throwing out most of your earlier work.

The step is basically to get the top can inserted into the bottom can. You can start by just using fingers to lightly bend the ‘flaps’ so they all get inside the can. Then you need to very slowly and evenly press the cans together. Using a small off cut of a can, or even a piece of card / thick paper, to help guide the pieces together. You want to avoid any ‘bulging’ in the top can, as when you push a bulge down, it will probably split the bottom can, which i did on my first attempt. Go slow. It does work.

Stove5
The top half being inserted. This is tricky

For the pot stand I came up with my own design, as I didn’t like the options is I had read about. I had some steel mesh left over from another project that I cut down and bent around a standard food tin. Then I used the top of that tin as a preheating pan and to keep the stove off the ground and so somewhat insulated.

I found a perfect sized plastic container and my little setup was done. The whole set up pictured weighed about 80 grams. Not too shabby.

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My first finished stove set

I did end up remaking this almost exactly the same, except I made the bottom half can taller, which left a small lip protruding just below the jets. The purpose of this was to make it easier to put on a simmer ring to slow down the burn for.. well simmering food.

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My slightly revised versions with a lip to catch the simmer ring (top right) and snuffing plate  (bottom right)

I had the chance to test it out in the field at Mt Buffalo some time ago. It faced off against a Trangia, a Jet-Boil, and a MSR Whisperlight. We did a race to boil 2 cups of water. It was windy and a bit wet, so a good test. I don’t recall the exact times, but my stove beat all three competitors, although I did note that the MSR seemed to be faulty and was having trouble holding pressure, and the Jet boil was a very old one, so probably not a completely fair test. But the point is that it definitely held it’s own.

Putting on that simmer ring is a bit of a skill, and I ended up needing to use pliers in my multitool i take camping with me. The first time I tried to just throw it in, it sat half in the flame and melted in a few seconds; be warned 🙂

I’m really happy with this little stove, and although I don’t get to use it much these days I definitely will continue to keep it as my main stove.

A word of caution if your are going to make one is don’t be silly with it. It’s home made and involves burning liquid, so be extra careful when building and testing and operating them. Although the same can be said if other stoves, you do have to be a bit more careful with these ones. For this style the main thing is to make sure that coin is in place or the fuel inside could catch alight. If that happens it could split apart your stove depending on how well you joined the cans together, sending burning fuel flying and giving you a really bad day.

Well I guess that’s it. I can throw out my bits and bobs left over from this project now. Breaks my little heart to move on projects but I’m determined not to become a horder. 🙂

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My last bits and bobs for this project headed for the recycling.

 

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