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.
Viewing 19 posts - 1 through 19 (of 19 total)
  • Author
    Posts
  • #1298331
    Colin Krusor
    BPL Member

    @ckrusor

    Locale: Northwest US

    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).

    stove

    stove1

    stand

    stand1

    stand2

    pad

    screw

    flame

    flame1

    flame2

    This is a photo of the stove from underneath:

    flamebottom

    scale

    #1946372
    Franco Darioli
    Spectator

    @franco

    Locale: Gauche, CU.

    That is a great looking stove !
    I like the ti stand/sleeve.

    #1946376
    John Donewar
    BPL Member

    @newton

    Locale: Southeastern Texas

    Colin,

    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

    #1946391
    Dan Yeruski
    BPL Member

    @zelph

    Locale: www.bplite.com

    Nice "dual flame" I like it. How tall is your pot support?

    #1946421
    Louis Jewett
    Member

    @lfjewett

    Great 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?

    #1946479
    Yohei Aoyagi
    BPL Member

    @zzz_bear

    Locale: Tokyo

    Nice job.
    Shara Project make a few donut styled hole alcohol stoves in Japan.

    http://www.shara-project.com/field/

    #1946500
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    Elegant.

    Cheers

    #1946610
    Nathan Hays
    Member

    @oroambulant

    Locale: San Francisco

    Now I know what I'll be doing tonight. Really, really nice.

    #1946640
    Dan Yeruski
    BPL Member

    @zelph

    Locale: www.bplite.com

    Thsi stove I designed years ago and Tony Beasley of Australia machined it for me out a solid piece of aluminum.

    The photobucket video was made with a camera that had a 20 second video application. Seems ancient.

    #1946735
    Colin Krusor
    BPL Member

    @ckrusor

    Locale: Northwest US

    Thanks 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.

    #1947706
    al b
    BPL Member

    @ahbradley

    Couldn't such a design have low CO emission?

    #1947720
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    > Couldn't such a design have low CO emission?
    Not guaranteed, but with the increased availability of air it is possible.

    Cheers

    #1965950
    Ktaadn .
    Member

    @ktaadn

    Locale: New England

    Beautiful stove!

    Where would you recommend me finding a small sheet of titanium in the same thickness of your pot stand?

    Thank you

    #1965955
    Angus A.
    BPL Member

    @mangus7175

    Locale: http://theshadedtrail.blogspot.com

    Talk about stove pr0n! That is a thing of beauty…very clean design.

    #1965965
    Jordo _99
    BPL Member

    @jordo_99

    Locale: Nebraska

    @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.

    #1965984
    Bean
    BPL Member

    @stupendous-2

    Locale: California

    I made this my desktop background.

    #1965986
    Ktaadn .
    Member

    @ktaadn

    Locale: New England

    Thank you JP

    #1966003
    Nick Larsen
    Member

    @stingray4540

    Locale: South Bay

    That 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…

    #1966466
    Colin Krusor
    BPL Member

    @ckrusor

    Locale: Northwest US

    Kasey, 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.

Viewing 19 posts - 1 through 19 (of 19 total)
  • 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!

Get the Newsletter

Get our free Handbook and Receive our weekly newsletter to see what's new at Backpacking Light!

Gear Research & Discovery Tools


Loading...