Coil stoves? I'm inspired, but cautious.

Post your new stove ideas here! All stoves welcome.
Image
User avatar
zelph
Posts: 15751
Joined: Tue Aug 14, 2007 1:53 pm

Re: Coil stoves? I'm inspired, but cautious.

Postby zelph » Sat Mar 07, 2015 6:47 pm

Interesting design. Eager to see it in action. My 1st one had flames that started at the jet and remained there through the entire burn. There was never any lift off of flame. The videos I've seen show the flame lifted off a good distance from the jet as if it can easily be blown out. Jet holes and wick size sure seem to be critical. :roll:
"Nothing Ventured Nothing Gained" stove store = http://www.woodgaz-stove.com/

churro
Posts: 208
Joined: Tue Feb 17, 2015 12:00 pm

Re: Coil stoves? I'm inspired, but cautious.

Postby churro » Sun Mar 08, 2015 11:52 am

I tried it out yesterday. No luck. I got it to roar a little, intermittently, but not reliably. Then I noticed the fuel plug leaks. I think I fixed the problem with a little epoxy. I'll try again tomorrow.

churro
Posts: 208
Joined: Tue Feb 17, 2015 12:00 pm

Re: Coil stoves? I'm inspired, but cautious.

Postby churro » Sun Mar 08, 2015 5:57 pm

The epoxy worked, no more fuel cap leak. However, when I was tinkering before I noticed the leak, I had been systematically widening the jets to try and get a better burn.Apparently, I went too far. It burned quietly for over an hour on less than 1/2 oz of fuel, but never did prime well enough to get a consistent roar. It would roar for a second or two, then lose pressure and go back to a quiet, fairly cool burn. So I closed the 2 original jets with epoxy and drilled a single jet in the center. When the epoxy has cured I'll try it out and then maybe install a priming wick to either side of the jet.

User avatar
zelph
Posts: 15751
Joined: Tue Aug 14, 2007 1:53 pm

Re: Coil stoves? I'm inspired, but cautious.

Postby zelph » Mon Mar 09, 2015 1:09 am

With the plug in the fuel port, does fuel seep out the jet hole ever so slowly? Mine does. Just the heat of my hands on the stove causes it to really seep fast. I suspect having it sit in the sun would cause it to empty the stove over a period of time. The capillary action of the wick seems to continue on when the can is closed tight.

The first stove I made roared all the time, the second one functioned just like yours, roared initially and then went into a real slow burn. :?
"Nothing Ventured Nothing Gained" stove store = http://www.woodgaz-stove.com/

churro
Posts: 208
Joined: Tue Feb 17, 2015 12:00 pm

Re: Coil stoves? I'm inspired, but cautious.

Postby churro » Mon Mar 09, 2015 8:14 am

zelph wrote:With the plug in the fuel port, does fuel seep out the jet hole ever so slowly? Mine does. Just the heat of my hands on the stove causes it to really seep fast. I suspect having it sit in the sun would cause it to empty the stove over a period of time. The capillary action of the wick seems to continue on when the can is closed tight.

The first stove I made roared all the time, the second one functioned just like yours, roared initially and then went into a real slow burn. :?

No, the jet being in the top of the can it sits above the level of the fuel. The wick just runs all the way through the copper hoop with no opening to the outside. There's no way to close it up for transport with fuel in it, though. If I can't get it working I plan to cut it open and see if the wick has burned. I'm thinking that it might work better if I get rid of the wick and just run the copper down into the bottom of the fuel reservoir. That way it'll conduct heat down into the fuel to vaporize it. That might prove dangerous, though, since I'll be heating all of the fuel, not just what gets wicked into the hoop. It might work better with a hoop or coil made from copper wire instead of tubing. I was thinking of making the jet out of some sort of adjustable valve to give me a simmer option and let me close it up for travel. This design will definitely need some tweaking before it's practical for travel, but I am having fun with it.

User avatar
zelph
Posts: 15751
Joined: Tue Aug 14, 2007 1:53 pm

Re: Coil stoves? I'm inspired, but cautious.

Postby zelph » Mon Mar 09, 2015 10:28 am

Long time ago, tinny at Minibulldesign made a stove that had a thumbscrew in the middle of it that extended down into the fuel to heat it up, pressurize it to get the jets roaring big time. I'll see if I can find a photo of it. The jets pointed inward towards the center where the thumbscrew was. The thumbscrew was screwed into the fuel port. He opted not to produce it for sale, was too radical for human use :o
"Nothing Ventured Nothing Gained" stove store = http://www.woodgaz-stove.com/

churro
Posts: 208
Joined: Tue Feb 17, 2015 12:00 pm

Re: Coil stoves? I'm inspired, but cautious.

Postby churro » Mon Mar 09, 2015 1:34 pm

That reminds me of the optimus knockoff I had as a kid, the kind with the big, heavy brass tank. The one I had was some cheap chinese copy. To prime it you just spilled a little fuel under the tank and lit it. The cap had a pressure-release valve in it, and I don't think there was a single time I lit it up that the valve didn't vent, then ignite, sending a little jet of flame in an inconvenient direction :o . I liked that thing, though. It was a blowtorch, and probably kept many a bear away while I was cooking (VERY LOUD!) I gave it to a buddy, and one day it just vanished. I think his mom threw it away while he wasn't looking, fearing it would blow up in his face.

Still not getting a consistent burn. The fuel cap leak is definitely fixed, so I tried out the first one again (the one with the big coil and long fuel port). It worked intermittently, but I think the jet is to big, because it loses pressure gradually, then goes out. The more compact one won't prime unless I take a propane torch to it, then the flame lifts way off the jet and blows itself out. Is the jet too small, then? Also, the 3/8" pipe I used seems to be too massive and takes forever to heat. I think the design could work with thinner pipe, but the whole thing heats up enough that it seems unsafe. I think I'll return to the coil design, using thinner pipe and and a smaller jet.

I definitely need to come up with some container for the body and construction method that can be disassembled for tinkering with coils, jets and wicks.

This is fun, but I am thinking that my non-pressurized stoves are much more practical.

User avatar
zelph
Posts: 15751
Joined: Tue Aug 14, 2007 1:53 pm

Re: Coil stoves? I'm inspired, but cautious.

Postby zelph » Mon Mar 09, 2015 6:14 pm

It seems like there is a fine line between diameter of coil, jet hole size and wick size inside coil. If there is too much fuel coming to the jet hole it roars radical and flame lift off is at max to where it almost blows its self out. When it's at that point a slight breeze can blow it out no doubt. :(

This video is of the first one I put together. The coil is a commercial one that I borrowed to make a more convenient backpack size. The coil seems to be at max size in all respects. Only drawback is it seeps fuel out the jets when least expected.....not good the jet holes are located in a place where the furnished plug does not cover/plug the jets for storage. :roll: :evil:

"Nothing Ventured Nothing Gained" stove store = http://www.woodgaz-stove.com/

realityguy
Posts: 5944
Joined: Tue Feb 24, 2009 2:20 am
Location: slightly north of Seattle,WA

Re: Coil stoves? I'm inspired, but cautious.

Postby realityguy » Thu Mar 12, 2015 9:22 pm

Did you(anybody) do any further testing as to the tank temperature..say raise the stove up a little in your hand off the cold stainless steel while it is burning to see if it changes the burn with the temperature of your hand(or a warm stove glove,hot pad,or something..under it)?I might have missed some results in my absence...
You guys are still pretty cold out there yet back east...I just wonder if you'd get a more consistent burn(and fuel flow) with a start tank at higher temperatures..say 60 degrees... :roll: With the stove burning,especially with a heat shield around it,I'm assuming the tank temperature would go through some radical changes..say 50-100 degrees at least..left on the cold stainless steel base. :geek: It might be really tough to get consistent burns.
I got a pretty steady burn with a commercial coil one but I didn't add the shield and the temperature is 50 degrees warmer.I didn't have a pot on top either..therefore nothing to change the temperature while it was burning..burned even for over an hour or so..
I imagine if the pot was high enough above the stove(and no shield or raised shield above the stove itself,only around the pot),you'd get a more even burn also..excess heat not forced back down to the tank and coil.
Don't Primus(Optimus..one of them) or some other stove recommend placing the stove tank in your hand to prime the burner and get fuel to flow for priming?..can't remember which stove's instructions said to do that...in colder climes.. :roll:
The views and opinions expressed by this person are his own and not the general consensus of others on this website.Realityguy

churro
Posts: 208
Joined: Tue Feb 17, 2015 12:00 pm

Re: Coil stoves? I'm inspired, but cautious.

Postby churro » Fri Mar 13, 2015 5:09 pm

I like your thinking, realityguy. I have decided to table this project, for now, though. I have to find a babysitter, cage the puppy and avoid our most inquisitive cat in order to do safe testing. I have a new project in mind that will be more practical for me. Here's a teaser:

Irrigation season is right around the corner. That means I will need to take our 8-9 month old son (he's almost 6 months now) out with me (in his off-road stroller) to flood the fields. I will need a way to warm water for bottles, so I was thinking of building a micro-stove and mating pot to do the job. Sure, it would be easier to just take a thermos of hot water to mix with cold, but anybody could do that. Besides, what better way to get my new camping buddy used to the basic chores of camping? The requisites I have decided on are small, convenient and wick-fed (to prevent fuel spills). I am gathering materials and mulling designs. The water will only need to be body-temp, so a quick burn is really all that's necessary. Maybe just a wick-wrapped steel bottle. Should be fun, if not all that practical or necessary...


Return to “Homemade Stove Ideas”

Who is online

Users browsing this forum: No registered users and 1 guest