Topic
Donut shaped center draft alcohol stove
Forum Posting
A Membership is required to post in the forums. Login or become a member to post in the member forums!
Home › Forums › Gear Forums › Make Your Own Gear › Donut shaped center draft alcohol stove
- This topic is empty.
-
AuthorPosts
-
Jan 22, 2013 at 10:20 pm #1298331
The outer part of this stove is made from the bottoms of two standard size soda cans and the inner is a segment of an old aerosol-toothpaste can (?). A wine bottle was used to flare the inner aluminum tube over the outside lip of the outer parts, to mechanically hold the assembly together and neatly finish the edge. That junction is also sealed on the inside by a small amount of high-temperature silicone. There are twelve pretty large holes in the inner part (about 1/16") and one hole in the outer part with a small allen screw for filling with fuel. A small mound of high-temperature silicone on the inside has female threads and seals around the screw when it's in place so fuel vapor only escapes from the jets. Fuel is added from a syringe that I carry in my first aid kit anyway.
I decided to try the donut shape because I thought it might be possible to construct a bowl-shaped windscreen that has a hole in the bottom and seals around the stove. I thought this might be a good way to prevent gusts from introducing cold air into the space around the pot (inside the windscreen). With a bowl-shaped windscreen that is sealed at the bottom around a donut-shaped stove, all of the gas around the pot is hot stove exhaust, and a chimney effect draws cold outside air through the flame. This idea might not be worth pursuing, but this was my reason for considering a stove of this shape.
In three boil tests this stove brought to a boil two cups of about 57F tap water in an average of 6:33 min. and burned for an average of 7:51 min. using 15 ml of a 50/50 blend of methanol and ethanol. In the photos below I added a pinch of boric acid to the fuel to make it easier to see (makes it greenish). The stove is primed by burning a small amount of fuel on a small disc of heat-resistant fabric (a "CarbonX" PAN knit). The stand is made from 0.01" thick 15-3-3-3 titanium. The stove, stand, and priming pad together weigh 15 grams (0.5 oz).
This is a photo of the stove from underneath:
Jan 23, 2013 at 12:56 am #1946372That is a great looking stove !
I like the ti stand/sleeve.Jan 23, 2013 at 2:26 am #1946376Colin,
Nicely done!
;-)” height=”550″ src=”https://dpcr19kltm61a.cloudfront.net/backpackinglight/user_uploads/1358936768_74499.gif” width=”550″ />
Impressive pictures and workmanship. :-)
When do we get to see the windscreen?
Party On,
Newton
Jan 23, 2013 at 5:38 am #1946391Nice "dual flame" I like it. How tall is your pot support?
Jan 23, 2013 at 7:51 am #1946421Great project!!! The one worry I would have is the High Temp silicone failing and the internal fuel assembly leaking. If it proves sound could this stoves flame be controlled by a air restriction plate on the bottom? It would give you a way to adjust from simmer to full blast with a BBQ style air intake?
Jan 23, 2013 at 11:27 am #1946479Nice job.
Shara Project make a few donut styled hole alcohol stoves in Japan.Jan 23, 2013 at 12:33 pm #1946500Elegant.
Cheers
Jan 23, 2013 at 7:06 pm #1946610Now I know what I'll be doing tonight. Really, really nice.
Jan 23, 2013 at 9:19 pm #1946640Jan 24, 2013 at 8:39 am #1946735Thanks for the responses. I'll post an update once I get a chance to finish the windscreen that I had in mind for this stove.
Dan, the pot is elevated above the ground 3.5", and it's 1.25" above the stove. The requirement for the stove to be elevated about 1" on its own little stand is one of the shortcomings of this design, I think. It pushes the pot up and requires a taller windscreen.
Louis, so far the silicone seems to be holding up. I added it as a precaution, but I'm not sure that it was actually necessary. The aluminum surfaces at the junction of the inner and outer parts of the stove are smooth, and they are crimped together pretty tightly. Besides that, the silicone at the bottom, that protects against leakage of liquid fuel, never gets hotter than the temperature of boiling alcohol, which is either 150F or 175F depending on the type (methanol or ethanol), and lower than that in the mountains. The silicone I used should tolerate temperatures approaching 800F (and higher for brief periods). That's high enough to anneal the aluminum of the stove, and much higher than normal operating temperatures, even right around the jets.
Jan 27, 2013 at 12:42 pm #1947706Couldn't such a design have low CO emission?
Jan 27, 2013 at 1:22 pm #1947720> Couldn't such a design have low CO emission?
Not guaranteed, but with the increased availability of air it is possible.Cheers
Mar 15, 2013 at 9:43 am #1965950Beautiful stove!
Where would you recommend me finding a small sheet of titanium in the same thickness of your pot stand?
Thank you
Mar 15, 2013 at 10:00 am #1965955Talk about stove pr0n! That is a thing of beauty…very clean design.
Mar 15, 2013 at 10:27 am #1965965@Kasey, searching Titanium foil or Titanium sheet on ebay should come up with a number of thicknesses and sizes that would work.
…likely you would want something around .005" or a little thicker…I know that's the thickness most windscreens are made out of.
I've been looking lately and found numerous sales that would give enough Ti for around $20 or less…likely being able to make a few of them.
Mar 15, 2013 at 11:15 am #1965984I made this my desktop background.
Mar 15, 2013 at 11:20 am #1965986Thank you JP
Mar 15, 2013 at 12:09 pm #1966003That is a pretty awesome little stove!!!
I would be interested to see you play with the hole sizes though. I wonder what a larger amount of smaller, needle holes would do to the boil times and file usage…Mar 16, 2013 at 5:51 pm #1966466Kasey, as JP says, Ebay is a good source for Ti foil. I've gotten most of the Ti foil I've ever used on Ebay. TiGoat, Seek Outside, Suluk46, and a couple other cottage backpacking gear companies also sometimes stock it.
Nick, I've considered a larger number of smaller jets, but I haven't had time yet to try it.
-
AuthorPosts
- You must be logged in to reply to this topic.
Forum Posting
A Membership is required to post in the forums. Login or become a member to post in the member forums!
Our Community Posts are Moderated
Backpacking Light community posts are moderated and here to foster helpful and positive discussions about lightweight backpacking. Please be mindful of our values and boundaries and review our Community Guidelines prior to posting.
Get the Newsletter
Gear Research & Discovery Tools
- Browse our curated Gear Shop
- See the latest Gear Deals and Sales
- Our Recommendations
- Search for Gear on Sale with the Gear Finder
- Used Gear Swap
- Member Gear Reviews and BPL Gear Review Articles
- Browse by Gear Type or Brand.