View Full Version : Penny Stove question
alverhootzt
09-05-2010, 06:58
I posted this in the wrong forum I think so I will try again..
I made my first penny stove and it seemed to come out ok, but I can't get it to jet. It still worked as a nice center burner stove (took 2 cups 6 min to rolling boil) and it didn't look like there was a leak in the side - just didn't jet.
After the boil I put the flame out and poured out the leftover fuel. I then had the bright idea to burn off the remaining fuel in the stove (I've since seen the caution on Jurey's site to NOT light it unless penny and jets were covered.) Still alive and what's more - the thing then jetted right away before burning out completely. Why? And what can I do to fix it so it does that when it's full? Any help appreciated.
Old Hillwalker
09-05-2010, 07:09
The slightly bent rim crimps that project down into the fuel must transfer enough heat to vaporize the alchohol and thus form the jet flames. Perhaps that is the problem with a large amount of fuel. When you dumped most of the fuel out, the heat transfer worked better not having a large quantity of fuel to absorb the heat.
Did you sand the embossed number off the top (can bottom) so that the penny gets a good seal whilst covering the fill hole?
It seems to me that it must be jetting because that's the only way a penny stove can burn. Of course HillWalker is right about he temp of the fuel, the hotter you get the fuel the better jetting you get. The best thing for you to do is experiment with the placement of holes and also the size of the stove. I built several of these stoves a few years ago until I found the combo of holes size, stove size, and holes placement that I liked. I have used nothing else since.
alverhootzt
09-05-2010, 10:19
I didn't sand. I used a very cheap brand soda can that had no punched numbers on the bottom. It's clearly thinner metal than both the Heineken and Coke cans I used for the other parts. Would that matter? I also pushed the burner pretty hard down into the base cap. Maybe I mushed the crimps. I will experiment with the holes. Thank you both for the replies.
Is this the penny stove that you constructed?
http://www.jureystudio.com/pennystove/stoveinstruct.html
To coattail on to the last two posts; You might try making the heinekien lip higher so that more of the flame touches the aluminum. This causes more heat to be transfered to the alcohol causing it to boil faster causing more vaporized alcohol to move through the "jets".
Getting the right balance between the number and size of "jets" along with the right amount of heat transfer to the liquid alcohol seems to be the key.
I can't say why the jets didn't light when the stove was full, but from experience I know that a full stove takes longer to "bloom" than a half full (optimist :D) stove. The reason for that is that alcohol has to be boiling to give off the gases that expand out the jets and support the flame, and that it takes longer to boil, say, a full ounce of alcohol than it does to boil a half ounce - bottom line - don't put more fuel in your stove than you think you need for each use, or you'll lose it in vapor before it comes to a boil and also after you extinguish the stove after a boil. A hot, unlit stove will vaporize left over fuel until it cools.
alverhootzt
09-07-2010, 05:00
Is this the penny stove that you constructed?
http://www.jureystudio.com/pennystove/stoveinstruct.html
Yes, that's the one. I've made 2 more - 1 with a brand name soda can as burner with holes in the crimps and 1 with a sanded heineken as burner and higher wall on the fuel cup. The soda can turned out the same - leaked is what it did, I guess, and the other jetted, woohoo! ... for about 20-25 seconds and then leaked also, but to a lesser extent. The last burned much hotter, too, boiling 2 cups between 4-5 minutes. I was trying to avoid the glue issue but I guess I have no choice. I can't seem to get a good seal. Again, thanks for the suggestions.
Copper Tail
12-05-2010, 11:14
If you use a Heineken can, definitely make sure you sand down the embossed numbers for a good seal. I use a large Heineken can stove. I get two cups to boil at 3 minutes flat. Just make sure you cover your pot and it will boil in no time. It takes more fuel to get it to operate but, I've discovered a very good simmer ring for it.
Take the top off of a coffee percolator (the lid of the reservoir that holds the coffee) and you'll find it is a perfect fit for the large Heineken can. The one I use channels the jets down to a single flame in the center where the rod pushes through the reservoir lid and makes a perfect simmer.
Has done wonders for my fuel preservation and much easier to extinguish when you are done too.
crazystick
01-21-2011, 02:17
I have recently been playing with the penny stove design as well from the site mentioned above. I was unsure at first but now I love it. I did my first boil tests today. I also got two cups of water to boil in 3 min flat. Then it simmered for another 8. I didn't measure my fuel though I just poured it in. I will do some more tinkering tomorrow.
Just a note though. Check your seal. I had to use jb weld for the seam on both mine to get a good jet going. I'm still unsure why my jets ar not totally blue tho I can see the flames easily... Using denatured alcohol.
Username75
01-21-2011, 03:26
There must be a way for the fuel to flow from the inner wall to the outer wall easily sometimes people use too much JB weld it plugs up the holes at the bottom that allows the alcohol to flow.
one should never overfill a penny stove, half way to the top is optimum
.
fill the stove, place Your penny
dribble a teaspoon of fuel on the top and lite.
it should blossom at room temp in less than a minute just from the top fuel.
I posted this in the wrong forum I think so I will try again..
I made my first penny stove and it seemed to come out ok, but I can't get it to jet. It still worked as a nice center burner stove (took 2 cups 6 min to rolling boil) and it didn't look like there was a leak in the side - just didn't jet.
Why? And what can I do to fix it so it does that when it's full? Any help appreciated.
Here is a quote from one of the links given:
DO NOT OVERFILL STOVE. A space above the fuel inside stove is necessary for proper operation and overfilled liquid fuel may be ejected instead of alcohol vapor, creating a potentially hazardous fire.I would venture to say is was over filled.
It still worked as a nice center burner stove (took 2 cups 6 min to rolling boil)That is a good performance for a stove that doesn't work.
Jets.....................we all like those little jets:)
You might want to check out Bill Waites site, as he has improved Jurey's stove(with his permission) I have his latest version and it is AWESOME...
www.acaircraft.com (http://www.acaircraft.com)
Odd Man Out
02-11-2011, 18:14
fill the stove, place Your penny
dribble a teaspoon of fuel on the top and lite...
I would caution you to follow the instructions form the web page:
"NEVER LIGHT THE STOVE UNLESS THE JETS ARE COVERED WITH FUEL."
Dribbling a tsp of fuel on top may not be enough to cover the jets. If you don't the fumes inside the stove will ignite at it will pop, sometimes spewing flaming alcohol quite a distance. I got burned once ignoring this warning.
I would caution you to follow the instructions form the web page:
"NEVER LIGHT THE STOVE UNLESS THE JETS ARE COVERED WITH FUEL."
Dribbling a tsp of fuel on top may not be enough to cover the jets. If you don't the fumes inside the stove will ignite at it will pop, sometimes spewing flaming alcohol quite a distance. I got burned once ignoring this warning.
I think there a lot that got burned just like you.
This type of info just fades away and is never seen again.
It would be nice if all the mods referred folks back to this thread to see time and time again.