Oct 21, 2007 at 4:02 am #1225511
This stove is similar to my first attempt which was really so so but has an important difference.
The body of the stove is a steel can that's 56mm(2 3/16th) in diameter and 37mm(1 7/16th) tall. The inner wall is made by using a second steel can that I realised was just the tiniest bit narrower at 54mm in diameter which creates a gap between the inner and outer wall of 1mm (what's that, 3/64th of an inch !?!)
Step 1 is to cut the top out of the first can but cut about 3mm (1/8th) in from the rim. I drilled 1mm holes at 10mm (7/16th) intervals about 5mm (1/4th) down. I also 'rubbed' the bottom of the can with a ball hammer sothat the bottom domed upwards, I did this cause it looks cool (!)
Step 2. was to empty out the contents of the second can and cut the bottom section off. Cut the bottom off sothat when it goes into the first can it touches it's bottom. (Second can goes in upside down). The base is cut out of the can about 5mm (1/4th) from the rim for no particular reason though it may help keep it sturdy.
Step 3. that 3mm bit of metal left when cutting the top off the first can needs to be changed so the second can will fit in. I 'rubbed' this edge with the round nose of a pair of pliers so it's curves into the can. Kept rubbing until I could squeeze the second can in. This creates a tight fit.
That's it I think. By chance the rim of the second can fits perfectly into the rim of the first can and step 3 helps seal up this area.
Weight: 1oz. / 30g
1oz of metho burned for 16 minutes.
At 22C (sorry don't know the Farenheit) 16oz of cool water boiled in 9 min 45 sec.
Side jets appeared after 25 sec and I gave it 1 minute before putting the pot on.
Pot is aluminium and I used a lid.
Sorry that photo quality is poor.
the two cans used same as these.
the rims of the two cans fit snug
away she goes
_____________________________________________________Oct 21, 2007 at 5:39 am #1406154
george carrBPL Member
@hammer-oneLocale: Walking With The Son
Very nice!! Better to be lucky tham good at times. I can't tell you haw many times I "eyeballed" a new stove design and it came together! BTW, 16 minutes on 1 ounce of fuel is awesome. FYI, 22 degrees C is approx. 71.6 F.
GeorgeOct 21, 2007 at 2:56 pm #1406181
@rcaffinLocale: Wollemi & Kosciusko NPs, Europe
> The body of the stove is a steel can that's 56mm(2 3/16th) in diameter and 37mm(1 7/16th) tall. The inner wall is made by using a second steel can that I realised was just the tiniest bit narrower
This is an 'open top pressurised stove. OK.
But what function does the inner can serve? Have you tried the stove design without the inner can? I cannot see any reason why it should not work just as well.
CheersOct 21, 2007 at 4:34 pm #1406195
Indeed, the inner wall isn't required with this stove type. Give it a shot without. And experiment with larger ports.
-MichaelOct 21, 2007 at 5:20 pm #1406200
I thought the idea of the inner wall was to create the small area where the metho can be heated from the 'inside' area and therefore produce vapour and a bit of pressure. Because this area is small (1mm wide) it creates a small amount of vapour against a relatively large heated surface that being the inside wall. I don't want the stove to work too fast and it simmers away the way I hoped it would. It also starts really well and does not die out when I put the pot on.
But I am new at this! It seems to work extremely well but your ideas can be experimented with on the next version.Oct 21, 2007 at 6:17 pm #1406206
Sorry Ian. I misspoke. You've got a good design for a open top high pressure side burner. But as Roger was leading, try an open top low pressure side burner with no inner wall and larger ports and compare the results for fuel consumption and boil times. You'll also get a lighter stove.
I'm curious about your "simmer". It sounds like you're getting a long burn time but how do you reduce the heat output for simmer? I don't see a simmer ability with high pressure side burners and usually approach those designs as a hot, fast burn for quick boils.
And what about aluminum vs. steel? I find aluminum to be much easier to work with, not to mention ultimately lighter. The Heine cans are thicker if you're concerned about strength, but I have yet to crush an aluminum can stove.
-MichaelOct 21, 2007 at 10:55 pm #1406239
I was wrong in using the word simmer, I was worried that because it has no way of regulation it may work too hot, I don't need to get to boiling point as soon as possible so am happy that it seems to work the way I want it to.
I will try the no inside wall method you suggest.
I'd much rather use aluminium but for this stove the challenge was to take advantage of these two cans being a slightly different size.
At 1oz I'm happy with the weight compared with when I used the Trangia fuel canister at nearly 3 and a half ounces.
The steel is easy to work with as it's on a small scale and thin, might rust in the future though.
I may stick with this design but need to test it for some time before relying on it !Oct 22, 2007 at 12:17 am #1406245
Ian, I really admire the use of available/recycled resources in developing your stove designs. You appear to have a solid stove that I'd be confident in relying upon. But keep in mind what you're developing the stove for. If it's freezer bag or "Mountain House", all you need is 190F (give or take); if you're cooking rice, pasta, baking, then you want the simmer ability over 20min. Tailor and refine your stove designs toward the task.
You're clearly driven toward MYOG and enjoy alky stove designs; check out and test all of them. Are you familiar with zenstoves.org and "SGT Rock's" hikinghq.net? That should keep you busy for many months.
-MichaelOct 22, 2007 at 6:29 am #1406251
Yeah, Michael you're right. Got me thinking how will this stove suit my next trip then my next thought was, how to make my next trip suit this stove ! I don't do anything hardcore so it should be fine. I probably won't do much or any more stove designing as I'll get waylaid by some other interest but I will test and fine tune this design as I'm happy with it.
You must be logged in to reply to this topic.