Hey guys, wanted to solicit some eh, thermodynamic advice. When I saw Zelph's Starlyte stove a few months ago (look here) I was really impressed by the simplicity and elegance of the design. But in my own testing the flame pattern was always very sputtery, as if the combustion was choked for oxygen or something to that effect. As I observed in another thread with larger-size tealight stoves, I suspected the flame pattern was too wide for its own good. So I've looked elsewhere.

Tonight I bought a tin of York Mints (here) and I'm intrigued by the possibilities. Now of course the tin itself is a lot wider, but I'm hoping to cut the burn hole in the lid much smaller than the total diameter, smaller even than the original Starlyte, hoping that will lead to a smoother burn.

I plan on filling this stove with fiberglass insulation, so my questions really pertain to how that works in holding / moving alcohol. I'm imagining this stove could have certain advantages over the Starlyte, so somebody check me here:
1) More alcohol can be held in this thing at one time. Longer burns. I can keep it full most of the time and simply cap the burn opening tightly while not in use. I'm hoping this will prevent any evaporation and allow me to simply light it up right where I left off the next time I want to boil anything. Yeah?
2) Since the tin is physically shorter, alcohol has to move a smaller distance against gravity (via capillary action) to get up into the burn zone, possibly allowing a more complete fuel usage than the Starlyte. Is this sensical? Does capillary action even take place in the FB?

If I soak the FB with alcohol and light the burn hole, can I expect alc to be drawn from the periphery into the center as the burn progresses?

Last but not least, I'm trying to ensure an efficient and smooth flame, and I'd like to use a Heine so I want most or all of it concentrated in the center of the stove. Any suggestions more clever or informed than a simple hole in the middle?

Thanks for your help guys.

You may have a bit of a misunderstanding here. What burns is vapour. What matters is getting the alcohol up to boiling point, to make lots of vapour.

So - adding lots more alcohol will mean more trouble and fuel for priming.
Capillary action in the fibreglass is either irrelevant or counter-productive. It's the metal which gets hot, and the more the alcohol is in contact with the metal the faster it will heat up. Fibreglass may be of some use in very tiny stoves to stop the alcohol from sloshing.

Cheers

Thanks for clearing some of that up Roger, I guess I didn't quite know those things. But really what I like about wick stoves or sponge stoves (perlite, fiberglass, etc.) is that they're easy to light and blow out, and they don't spill alc all over the place if you manage to knock them over. That may seem like a remote possibility and I'm not really a clumsy person . . . but I do like that insurance.

Or maybe it's just an aesthetic thing, but whichever.

So I think I want to go ahead and build a FB stove anyway. For an open-flame style burner like Zelph's starlyte, can someone explain to me how alcohol behaves as the stove is lit and heats up? In a simple open tealight, it appears to me that the heat from the flame heats up the body of liquid alc enough that it begins to boil, but that those boiled vapors don't ignite until they encounter enough heat and oxygen, which would be where the flame forms. Is this process basically the same as what happens inside a spongy stove too? Are boiling alcohol vapors moving up toward the flame through the fiberglass?

If that's right, then I guess my next suspicion would be twofold:
1) Any alcohol in my theoretical York Mint tin that's soaked into the periphery of the disc will vaporize and find its way back to the opening in the center where it can burn.
2) It will steal quite a bit of the stove's heat output just to keep that alcohol on the periphery at boiling point.

Now am I getting it?

Edited by freeradical on 03/02/2008 09:57:09 MST.

> Now am I getting it?
Yep :-)
Experiment!

I think this topic would be great for an article. I would like to see how design changes effect how an alcohol stove works in the winter. I know Tinny likes the wick stoves he makes like the blackfly II during the winter. The wick could be increasing the ease of lighting by increasing the surface area of the alcohol exposed or it could just be that the water jacket helps keep the alcohol above freezing, kinda like keeping a canister in water.

Jason, my understanding of why it's easier to light Tinny's BlackFly 2 et. al. is not exactly because of increased surface area but just that the amount of alcohol that your lighter needs to heat up to vaporization held in the capillary of that tiny loop of wick is a LOT less than if you were going to lower the flame to be in contact with the main body of the stove, or the main body of fluid.

That is, the process of using capillarity to draw alcohol up to the flame zone (which I tried to describe in my initial posts at the top of this page) is, I'm pretty sure, NOT what happens in Zelph's Starlyte, but it IS what happens in Tinny's BlackFly. The flame can't radiate heat onto the main fuel reservoir because the reservoir is shielded by the top of the stove, and back-conduction of heat into the fuel reservoir is, I think, mitigated by A) the water jacket keeping the stove body cool, and B) the only other potential link between the reservoir and the flame being a very small diameter non-conductive wick.

So, if I've sized this up right, a wick stove like the BlackFly is easy to light because you only have to ignite the smidge of alcohol that's held in that top half-inch of wick, AND the chance for heat to be drained away by other parts of the stove have been mitigated as described above.

In the Starlyte stove, I'm now pretty sure, for the stove to really prime up it needs to "back-radiate" and "back-conduct" for a little bit in order to bring most or all of the alcohol inside to vaporization, just like most alky stoves. And just like most stoves, these kinds are somewhat difficult to blow out once they've primed.

you could put out a typical (non-wick) Alky stove (i like that Ian) by cooling the stove walls so that vaporization would cease. Further, if your small pop can stove was in a small dish, you could pour cold water in that dish, around your stove and it would go out and you could then save the unused alcohol?

Edited by barber5 on 03/20/2008 13:43:56 MDT.

It's the free radicals on the surface of the StarLyte that make it so easy to light!!!!!! Alcohol wants to evaporate!!!!Expose it to air, and it evaporates. The fibers inside the burner are lined up in the verticle position, 99 percent of them. They are in extreme close proximity of each other, hundreds of thousands of them right next to each other. Very nice conditions for capillary action to bring the alcohol to the surface where it meets up with oxygen. It's right there ready for a heat source to ignite it. I was just kidding about the free radicals : )

Quote)In the Starlyte stove, I'm now pretty sure, for the stove to really prime up it needs to "back-radiate" and "back-conduct" for a little bit in order to bring most or all of the alcohol inside to vaporization, just like most alky stoves. And just like most stoves, these kinds are somewhat difficult to blow out once they've primed.(end quote)

Take a peek at this movie that may daughter made while I was using a StarLyte burner to thaw out my door latches. It was a -13 degrees in St. Paul MN in January of this year with a wind chill factor of -30 degrees at the time of this movie being made. There is no need to "back-radiate and "back-conduct" to have the StarLyte ignite.

Sorry, I was told Forums Image Upload
Sorry, but only gif, jpeg, and png are supported.

I'll have to get you a link to it.

Let's see if this works Starlyte Burner Movie

This is what the latest StarLyte stove looks like. It is now a complete stove. Potstand is attached and is made of stainless steel wire. Stove weighs 14 grams has a 1 ounce fuel capacity. Lights easily in -13 degree weather.

Edited by zelph on 03/20/2008 16:21:05 MDT.

Ian, what's the latest on your York Mints stove?

Any photos and test results?

None at all. I abandoned the idea after I realized (in the posts above) that the whopping circumference of the stove would mean quite a lot of alky to heat up, which would rob the stove of a whole lot of efficiency.

Anyway, the CFV concept in the other thread seems much more promising. Ever since I saw your ROF I've been trying to figure out . . . something. And that may just be it. Extremely simple in form and construction, very compact, easy to retain alcohol held inside the stove (well, that's what I'm working on, anyway), efficient, light, usable with many different fuels . . . what else do we want?

Oh yeah, and STABLE! More stable than a Caldera Cone!
(depending on how you determine that, anyway)

Edited by freeradical on 03/25/2008 19:52:05 MDT.

I realize this is kind of an older thread but with regards to the York Mint tin... I'll post a DIY of some kind within next few days of how to use it as a wick stove that you can pick up and move around. Really, it isn't anything new or enlightening, just twisting an old idea. Essentially, use cotton yarn for wick, run it thru some medical silicone tubing, run the tubing thru a hole on the lid. Place a 1/2 ounce alcohol in the tin bottome, set wicking down into tin bottom, press lid into place and light. Works fien in cold weather. Had it outside last night here in Bozeman. It was 25 degrees. Will burn 25 minutes on that half ounce. I am wanting to use it for baking, not boiling water.