PENNY STOVES

[KANANGRABOYD]

So I have seen these around the internet for a number of years, but never got around to actually making one. So last night I decided to make one and see how they fare against other stoves etc. I made just a plain "penny" stove from 2 coke cans and the whole process took around 30 mins.
There is a guy from Japan who is the absolute "master" of popcan/soda can/alcohol stoves named "TETKOBA"... I am sure many other members know about his YouTube site and just like me am amazed at how he comes up with his incredible stove designs.
So this afternoon I went out to the shops and bought some art knives, a circle cutter and sandpaper......just need to get a product that he uses often in his stoves called " JB-Weld".
Anyway here is my lil stove.
I also made a lightweight pot stand from coat hanger.
Specs:
1 lt of tap water boiled in 9.47 mins using 35 ml's of Metho.
Boil time for same using windshield in 8.30 mins
Stove weight including 5 cent piece = 13 gms.
This was done inside in my shower of all places so not outdoors.
As far as I am concerned, these stoves are amazing and fun and actually give gas a run for it's money.
I've ordered some JB-Weld - and gonna try making Tektoba's "premier" stove called the " Hoop Capillary Stove" - just need to down a tonne of Red Bull's.
I'd love to see other members creations.....so............ SHOW ME YOUR STOVES!.

PENNY7.jpg (546 KiB) Viewed 10366 times

[ULWalkingPhil]

I tried making a few of the penny stoves with little success, one of them actually exploded on me, the pressure built up to much and next thing. BOOM!

[icefest]

Mine are quite well loved. I've been using them for a year. Mainly on overnight trips, where they are lighter than a gas stove.

[Strider]

just need to get a product that he uses often in his stoves called " JB-Weld".

This appears to be near identical to the Dev-Con product we get in Australia, except JB-Weld can handle 500F whereas Devcon only 250F.

[andrewa]

I used some ?aluminium flashing tape to join the 2 sections. You can also use locktite apparently. I love these little stoves for certain uses. We used one in NZ last yr for our breakfast coffee on a 10 day fly fishing trip. I recall that about 25 mls of metho boiled about 400 mls of water each day for this. We cooked dinner (fish) each night on a fire, so, for that use, it was quite light and efficient. Not for ski touring/ melting snow though....it just comes down to how you wish to use them.

BTW, A pathology specimen jar holds 50 mls of metho, and just happens to fit perfectly inside the stove for short trips..

Mine's not a penny stove though. I did try the cat food tin stove, but it didn't work as well for me. Haven't made a penny stove yet, but they are all similar concepts, and fun to make and use.

Andrew A

[simonm]

just need to get a product that he uses often in his stoves called " JB-Weld".

This appears to be near identical to the Dev-Con product we get in Australia, except JB-Weld can handle 500F whereas Devcon only 250F.

Jaycar have JB Weld http://www.jaycar.com.au/productView.asp?ID=NA1518

Those stoves by Tetkoba are masterpieces aren't they.

I made a basic stove out of coke can once - it looked rough but it worked ok. Might be time to revisit.

[michael_p]

JB-Weld

You can get JB Weld at Jaycar stores. Super Cheap Auto have a high temp two part epoxy or you can use a high temp silicone (also from Super Cheap Auto).

You can get a range of templates from http://zenstoves.net/Templates.htm. I found these very useful when I started mucking around with stoves.

I have made a number of different soda can stoves including several variations of the penny stove. To be honest I prefer the open bath type (see andrewa's post) over the penny type but YMMV.

Cheers,
Michael.

[michael_p]

I used some aluminium flashing tape to join the 2 sections.

Nice solution. I hadn't thought about binding them with flashing tape.

[michael_p]

Just remembered this. The scoop from a tub of gatorade is about 20ml. Makes measuring your metho out a lot easier.

[Strider]

This is another good design mentioned here previously

http://www.alastairhumphreys.com/how-to ... ever-need/

[Orion]

I tried to make one based on instructions I read online somewhere and wasn't successful. It didn't explode, it just worked so poorly that I couldn't even boil water with it.

For those of you who have had good results: Did you have to try more than once? Any clue as to what the key design feature is?
Here's mine:

[Franco]

Kanangraboyd,
looks to me that your stove is burning too hot (yellow large flame)
A couple of things you could try.
Put more fuel at the start and then use a snuffer to put the flame out.
Or, try mixing in about 15% of water with the metho,
Or ...both of the above

Snuffer :

https://www.youtube.com/watch?v=poDcCH_ ... ex5BMVK4vw

[Strider]

Orion it could perhaps do with a few more holes to let the fire out???

[Orion]

Strider, I don't know. That's why I was asking for help from those who have better stoves.

I just copied the instructions from here: http://www.jureystudio.com/pennystove/penny2.html
Their stove (which they say will boil 0.5L of water in under 5 minutes) looks like this:

[Franco]

Most of the stoves you see on the net were tested with methanol (like Yellow Heet) or a methanol/ethanol mix, like SLX.
our 95% Ethanol burns hotter and that is why I suggested several times adding some water.
I know that it may not make sense but try it anyway...

[michael_p]

Orion,

I've had the same problem. You don't have enough holes. Try adding extra smaller holes between the existing ones.

I built a stove that only had a small number of holes and it just would not keep burning. I did get it to work but had to use a lot of priming. I then tried adding extra holes and it worked but not very well. Having built about 20 stoves now I've found lots of small holes has worked best for me.

Michael.

[ULWalkingPhil]

The penny stoves I made are from instructions for use with my Backpacking Oven, I have posted about this somewhere here on the forum in the past. it only has 3 holes drilled into the chamber, It was very unreliable, kept on going out and one stage actually exploded and the two parts came apart and I did add water to the methylated spirits. I have made a stove very similar to what Kanangraboyd has made, it's not a penny stove, I modified the top of the stove on mine, works great and very fuel efficient.

[ULWalkingPhil]

My stove is very similar to the penny stove, originated from a penny stove.

Kanangraboyd, you have more holes in your stove than I do, I'm wondering if I should add more holes on mine.

I just boiled a cuppa for a trail test, boiled two cups of water in 6 minutes and 10 seconds. Used just over half an ounce of fuel.

[icefest]

I tried to make one based on instructions I read online somewhere and wasn't successful. It didn't explode, it just worked so poorly that I couldn't even boil water with it.
For those of you who have had good results: Did you have to try more than once? Any clue as to what the key design feature is?

I used an (from the looks of it) identical design.
I find that you need to fill it such that there is a puddle of metho over the coin. That then burns and warms up the reservoir below.

In cold weather you need to bath it in flames (warm up the metho), I do this by pouring some into the lid, then resting it on the lid and lighting it. See image 1
I have also made longer sidewalls, these conduct heat to the reservoir, and boil it faster. Image 2
Getting a decent seal with the coin is also important.
Contrary to other experiences I find 6 holes of ca .8mm perfect. I have tried both 8 and 4. Eight was harder to light and I had runaway flames with four. Image 3

With my current setup, if you rest the hot pot on the stove there is enough heat conduction to vaporise some metho and continue a slow simmer. I use rocks to support the pot and spread them around after use.
Tell me if you want photos of it burning.

[Orion]

Icefest, thanks for that. It leaves me puzzled though as I primed like a madman, engulfing the whole thing in a giant puddle of burning fuel at one point. The stove only worked as long as it was being primed. As soon as the priming liquid was gone the stove began diminishing in output power, ending up just barely running at all. I couldn't boil 0.5L of water with it.

I would estimate the hole diameters on mine to be roughly 1.2mm versus the 0.8mm on yours.
The other thing is that I used a 50-50 methanol/ethanol fuel mixture instead of 95% ethanol.

[icefest]

I'll time the stove tonight and take some photos while using and priming it.
I really need to find a 1 euro cent coin. Extra light.

[Strider]

I'll time the stove tonight and take some photos while using and priming it.
I really need to find a 1 euro cent coin. Extra light.

NZ 20c and 50c coins are super light too.

[Supertramp]

6 holes being 2mm in diameter is more than enough for these stoves.

That is what mine has and it is perfect. I even went to the trouble of sanding mine so it was 100% silver, took me over an hour to do!

[Supertramp]

This is what mine looks like, I haven't timed how long it takes to boil water yet.

[icefest]

Wow, so pretty.

[Supertramp]

Might have to try a 5c piece, see if I can't save some weight

[icefest]

All links go to images showing extra details

I did some test burns with scales, timers and other whizzniks.
The first one I filled the stove all the way to the top with fuel, the way I do when it's very cold and the metho doesn't evaporate well. I then timed how long it took to boil 500ml and put out the flame and weighed the stove.
The second one I only just filled enough to boil, then weighed the leftover fuel.


The following is a table of my boils:

In summary, I used between 14-19g of metho to boil 500ml of water, in ~10 min.
A windscreen and/or heat exchanger would improve efficiency. (and a decent lid, I just used the closest hiking pot I had lying around)

The last 8g were burnt with the pot resting on the stove ('simmer' mode). It continued to burn for another 4:20 min.


Fuel and water amount was determined by weight, on an calibrated kitchen scale (+/- 1g), timer was an ipod (+/- 10 sec).


Extra photos:
When it was first lit, warming up.
When it was burning at full speed

• Another one
  
• and another one

"simmer" mode