Gram Weenie stove

Jonathan,

How many rows of holes does your have. I intially sent out about 6 stoves before I caught the problem, and I thought I had sent everyone the updated stove. PM me and let me know.If it's the single row I'll sent you the updated stove right away.

so what do i have to do to buy one of these stoves?

Do what George recommended that I do: go to his Web site and just order it online!

I got my stove two days ago and played with it a bit; it’s small but looks really rugged, more crushproof than any alky stove I’ve handled. At 30′ above sea level I got boil times with 12oz. of tap water around 6:30…I couldn’t get 16oz. to a roiling boil on the standard 1/2 ounce of fuel…I’m optimistic this could be different in the mountains, but with wind, who knows. On my next trip I’m taking both my AGG Caldera Cone/Kitchen/SUL500 mug and the gram weenie to have a high-altitude boil-off!

Hats off to George for an insanely clever idea. The stove is minimal, built like a tank, hot as all getout, and a perfect fit for mugs and super-small pots. A Gram Weenie-based cooking system – all components except, ahem, except my BPL spoon! – fits inside a the SUL500 mug! :-)

Are you guys putting a row of holes around the bottom of your windscreens? If so, are they going all the way around–or just partially around? How much space between the pot/mug and the windscreen? (I'm new to alcohol stoves.)

Scott,
The windscreen included with the gram weenie is minimal to begin with, and you probably won't be happy putting holes in it. Because of the small size of the stove it is very responsive to adjustments to the windscreen, ie; if you want the stove to burn a little hotter close the gap around the pot, and open the gap a little to cool the stove a bit. That being said, if I were going to put holes in the screen I think I'd just put them on one side along the bottom, allowing you the option to turn the windscreen around for a total windbreak.
George

Geroge:

I too am intrigued by your stove. Can your stove bring 2 cups (16 oz) of water to a rolling boil as a matter of routine — using a FireLite 550 pot?

Ben,
I've been playing with this stove today and using an MSR Titan pot I have gotten 2 cups of 60 degree F water to 205 degree's with 1/2 oz. of alcohol repeatedly. The elevation here is about 750 ft above sea level. I could not get a rolling boil, but 205 degrees is just fine for what I usually "cook." I've noticed a lot of folks don't post the starting temp of the water. Others start with 70 degree water. I assume that if I'd started with 70 degree water I would have gotten a rolling boil.

I had posted my first test of this stove here and did get a rolling boil that one time, but have not been able to repeat my original results.

Hope this is helpful.

-Mark

Thanks for the feedback, Mark!

Ben, the gram weenie was designed to boil 12 ounces of water, and that it does well. I never expected 16 ounces to boil, but as Mark pointed out, it will under optimal conditions. I'm also in the camp that if I can get the water temp. close to boiling that's good enough for me, as I mostly reconstitute dehydrated/freeze dried meals. Unfortunately it's a tradeoff b/c if I made the stove taller to gain more fuel capacity it would lose stability and gain weight. While the stove works extremely well with a keg pot, it really does shine under the firelite 500 pot. I have to say, the more I use it the more I like it!

George:

Thanks for the feedback. Your stove is both imaginative and impressive! :)

Ben, Mark & George:

I've been playig around, making a few of these stoves and have been getting consistent 8:20 roiling boil times on exactly 1/2 ounce of fuel using measured 2-cups of cold tap water. I am also now getting total burn times of 11 minutes flat! (I live at 200' above sea level)

Here's how: The trick was to simply use a hammer and with a couple of quick blows, flatten down the rounded inner bottom portion of the base so that it doesn't stick up into the chamber.

That effectively gained me the extra space needed for the 1/2 ounce of alky and I didn't have to extend the height at all!

Steve,
I am a little confused about the modification.

As I see it there are two parts to this stove: the BASE which is a cylindrical cup cut from the bottom of the bottle and what I would call the INSERT which is the top of the bottle inverted into the BASE. So given this terminology which part do you hit with the hammer? Do you do this prior to assembly or after assembled?

I have no problem putting in 1/2 oz and in fact can get about 0.1 oz more if careful.

Finally, and most importantly what is the starting temperature of the water you are boiling?

Thanks,
-Mark

I just can't get a boil after more than a dozen tries (fiddling with the windscreen between tries.) I've got small bubbles on the side of the mug (Snowpeak 600 with lid) and I'm sure it's hot enough for my uses, but I'm jealous that everyone else is getting a boil and I can't. On my last attempt, I used 12 oz of tap water at 71 degrees. Still night at about 1800' above sea level. The windscreen is about 3/8 inches from around the cup. From the time I lit the alcohol until it went out was 6 minutes and 45 seconds. I'm using S-L-X denatured alcohol from Lowes. I'm wondering if the extra mass of the Snowpeak 600 is holding me back. Do I need the Firelite 550 or beer can in order to get a boil? Anyone else have success with the SP600?

Scott,

I'm using S-L-X alcohol and the MSR Titan pot which is slightly larger than the Snowpeak. A wider pot bottom is pretty important for heat transfer from what I understand. I doubt the mass of the pot has much to do with it (see Roger Caffin's article at http://www.bushwalking.org.au/FAQ/FAQ_StovesTech.htm#CO for a great education on stoves). My own experiments with a 24 oz beer can pot and the gram weenie stove showed that I could only get the water up to about 180 to 190 with 1/2 oz. of alcohol. But the same stove with the MSR pot got up to 205. I think mainly it is due to the surface area of the bottom of the pot in greater contact with the flame. However, I am definately getting a longer burn time than you, but I've been doing it in my kitchen and not in the field.

You might try a wider pot just to see if that changes the temps you get.

-Mark

After lots of frustration trying to use narrow pots (snow peak 450/600/firelite500 etc) with alcohol stoves, I've reverted to an old standby: The Evernew 0.9L Pot. It's only disadvantage is the larger size/packability, but weight wise it's extremely light, especially considering it's capacity. My pot with the handles removed and without the lid weights 2.1 oz. That's lighter than a SP600 with the handles removed. Add a pie tin foil lid and the complete setup is only 2.2 oz. That's the same weight as my firelite 500, and the larger size and capacity is much easier to deal with. If you use the stock lid, it's still only 3.3 oz (handles removed).

Additionally, I have been consistently getting full rolling boils with 20 ml of alcohol, (something I've never achived with narrow pots-excpet with the caldera cone) which actually weighs under 0.5 oz, so lighter than ESBIT (which I am a big fan of).

Hey Scott,
Are you filling the stove to the top of the neck? Also, try the HEET in the yellow bottle. IMO it burns a little hotter.I used to burn every stove to ensure a minimum 7 1/2 minute burn time. I now burn about 1/2 of every batch at random to ensure the same. To get the full burn it is necessary to fill the stove to the top of the neck (the narrow area). Let me know if this helps. As far as the pot goes you should be fine with the snowpeak 600.

Mark,
Steve means the raised area in the bottom of the stove. I waited until now to post on the mod to try it for myself 1st. I have built a 1/2 dozen with the modification in various height and jetting configurations and can't consistantly repeat Steve's results. I don't doubt his numbers, but I only got an 11 minute burn twice, otherwise my burn times haven't increased significantly (average about 8 1/2 minutes). I got a slow boil a few times, a fast boil most times, and a rolling boil in 5 1/2!!!!!!! once.I'll continue to work on it, as the ability to boil 16 ounces with this stove would be a real plus. Obviously it can be done, since I had it happen in an amazing time for such a little stove.

Steve, give us a hand here. What about the jetting? Also, did you still put weep holes in the neck? Also, are you using the same bottle, or something a little different?

Mark: George is correct in saying that the "Hammer time" modification is to the BASE and it is accomplished before final assembly. The aluminum bottles are the 80ml ones from "Sun Burst Bottle."

I dinked around with jetting modifications and found something unusual: Just using the 3/64 drill bit holes, staggered like George did, about every 1/8 inch around the side of the stove, I got a longer burn time, (just over 11 minutes) but it took 8:20 to boil the 16 ounces of water. I then used the same staggered pattern, but used a combination of the 3/64 holes placed above an equal number of 1/16 holes below. I also spaced them a little further apart, so I had a few less holes. The height of the holes on the side of the stove remain the same.

The one-time, very fastest boil time to date is 4:55 for 16 ounces of cold tap water, using a Primus Tea Kettle for the container. (Gotta wonder if the wider base of the Tea Kettle has something to do with the shorter boil times??) BTW…That boil time is timed from when the flames first "blossom" out the side holes. Sorry Mark, I don't have a thermometer to test the initial water temp, but it is quite cold tap water. Also, "boil" is when I can see and hear the bubbles and heavy steam is coming out.

The unusual part was that while using this "new" jetting pattern, the boil times went down (Yay!!) but the total burn time also went down to about only 7:30. Not a huge issue since the initial boil time is also lower. Note that the majority of the initial boil times are in the range of 5:30 – 6 minutes though. Someone please tell me why I would get the one time fantastic boil time and the rest are more consistent???? (Conditions in my garage were the same)

Edit: George…weep holes are still placed on the neck as before.

Steve.

Steve,
Thanks for the insight. I've been beating this around in my head all day, even came up with a few new stove ideas that I tried out today. The one thing that sticks out in my mind is,if you flatten the base, but still bottom out the neck piece, you don't really gain that much more fuel b/c you lose the fuel that would have been in the area around the base of the concave section.I'll have to measure and compare the two configurations. I think the boil times are more a function of the jetting. I'll definitely try that tonight. The difference between my boil and your boil is that I only consider a rolling boil a true boil. That's just my standard. If I count heavy steam and the sound of bubbles I am already duplicating yor boil times. I still can't explain the anomily (sic) of my 5 1/2 min. rolling boil, but it just shows it's possible.

George: I'm not sure I follow your meaning regarding the fuel that was lost around the concave section, but a before and after measure would certainly seem to be in order.

I suppose that I should go and buy some sort of thermometer to accurately measure the water boiling temp, so we can compare apples to apples.

Thanks for the quick reply!

George-

I tried HEET as you suggested, and I finally got a rolling boil. It also extended the burn time to just over eight minutes. This is such a cool little stove!

George and Steve,
Thanks for the clarification on the hammer mod.( This is where I hit my forehead and say, "Dooh!").

George: I was wondering why so may jet holes in this stove (66 in mine). Does this improve the efficiency or the heat output in some way? This stove in it's present form has an efficiency of 53% by my calculations which is pretty incredible. (Based on the energy present in ethanol it should take about 8ml of alcohol to heat 16 oz of 60 degree water to 212 degrees by my very rough calculation.) That would be 100% effecient.

Well, keep up the good work.
-Mark

Mark,
I wish I could tell you I have some special formula (which is TOP secret, and I could tell you but I'd have to blah blah blah…), but the truth is I come by my jetting by trial and error, and experience.The staggered jetting is something I have been using for some time in my Thru Hiker stove (which has 42 burner holes), so since it has a track record I sometimes incorporate it into my designs. It seems to burn a little hotter than a straight row of holes. It's like I used to say, "Sometimes I'd rather be lucky than good". :-)

Scott,
That's good to hear. I always recommend the HEET in the YELLOW bottle if you have a choice.

Darn, And I thought you were going to let me in on the special formula…
Still, it's a nice stove.
-Mark

I put the gram weenie through its paces for six days last week in the Entiat mountains in Washington. It worked like a charm. The fuel efficiency was particularly appreciated, especially since I ended up needing to use it for both me and my climbing friend who accidentally only brought enough fuel for her Snowpeak for one day.

That's awesome Kathleen! I'm glad your stove was able to perform above and beyond the call of duty. :)