Odd Metal jars

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PyroJoe
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Odd Metal jars

Post by PyroJoe » Wed Oct 17, 2007 5:50 pm

I have been having some success with oddly shaped/hammerd oxygen canisters. There is a section of 3/8 NPT pipe (actual O.D. is .675" actual I.D. is approx. 7/16") with length of approx 1-1/8" protruding into the CC. Height of the canisters have a finished height of approx 6.5".

They run well on methanol (HEET).
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PyroJoe
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Post by PyroJoe » Wed Oct 17, 2007 5:54 pm

Here is a clip of the one on the left. Forgive the crazy Texas accent.
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PyroJoe
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Post by PyroJoe » Wed Oct 17, 2007 6:13 pm

Here is a aluminum can smashed like The one on the right above. It is on a string and the video was taken sideways.

This is my lightest jar yet. Weighs in at 1/2 ounce fueled. Glued seams with J/B Weld.

It only cycled two or three times.
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Post by PyroJoe » Wed Oct 17, 2007 6:15 pm

Wondering what to name these things. Any suggestions?

Mark
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Odd Metal jars

Post by Mark » Thu Oct 18, 2007 1:57 am

That's interesting the simple flattened one on the right runs, I would have guessed it would have been fussy. Did you make a video of it? That's a new kind of jam jar profile to me. Instead of one intake in the middle, I wonder if it would tolerate 2 intakes, one on each far edge of the top? So many things to try and think about with these little guys.
The four finned one ran for an appreciable amount of time, maybe with a water bath it could go even longer.
Is the aluminum can a typical Coke can or something thicker? If it is made of thin aluminum, the erratic flexing of the walls will probably dampen the feedback, not to mention a sideways flow will toy with the fueling laying on its side like that, if you are just relying on putting some methanol in the can and firing it hanging on a string. Lots of movement to contend with.
The best thing to me about jam jars is that they are often made of things most people throw away.
Good odd metal jar work there Tex.
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PyroJoe
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Post by PyroJoe » Thu Oct 18, 2007 1:32 pm

Yes the flattened one runs till the fuel is gone. It is about half as likely to start as the "X" one, but after it starts it will run just as long. It has a strange start mode about one in four starts.
Instead of the sharp dart and shrill woosh, it has a lazy flame dart about 6 inches long that slowly sinks down into the CC and then starts, it's really a site to see.

I'll try to get a video of that one soon.

I try not to run the canister types for more than a minute. The paint starts smoking and puts of an arid smell.

I cut a small circle of red shop towel and put it at what was the bottom of the aluminum can. A carefully cut circle of chicken wire holds it in place. I think it would be better off without them. I think they run better when the methanol is allowed to slosh around instead of being trapped in something absorbant.

The aluminum can is a Keystone Light beer can, If I remember correct it is a 18 ounce can. Nicknamed the "Keystone Special". ha
I fabricated a aluminum tube that scaled/duplicates the 3/8" NPT pipe and glued it in the same place. My next aluminum jar is in the works. It is a 24 ounce Coors "Silver bullet". ha

---UPDATE 1/22/08: discontinued epoxy assembly of aluminum cans due to the continued failure rate of the seams.


This weekend I will tinker more with the sideway running properties, have some ideas to test.

It's funny you brought up the two hole idea. I have planned this weekend to test a Logan style, two hole jar design in a full length oxy canister. If I have enough time I will try a two hole in the smashed flat design also. Not sure where to begin with diameter sizes for a two hole.

So far the best run on it's side version is the four fins.
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larry cottrill
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Post by larry cottrill » Thu Oct 18, 2007 3:19 pm

PyroJoe wrote:I think they run better when the methanol is allowed to slosh around ...
From what Mark has observed before, this part of your observation is probably not correct.
... instead of being trapped in something absorbant.
But this part very well might be! It's possible that the evaporation is slowed down by the absorbent material, especially if the available surface area isn't much more than that of an unrestricted pool.

Try something that will kill the sloshing but leave plenty of smooth liquid surface exposed, like a disc cut from the grille of a small cooling fan - the kind that's commonly called 'expanded metal', and see what that does.

I have speculated before that the reason "real" jam jars (e.g. Smucker's jars) work so well is that they have almost perfectly flat bottoms (in the interior) - that means you can cover the bottom with a very shallow pool. A shallow pool will have very slow, retarded wave action, whereas a deeper pool will have a very excitable, high-speed wave action. That could make quite a difference. It always seemed to me that the ideal fueling situation will be where the blast of air comes down the center and mushrooms out, "scraping" the maximum amount of vapor off if the surface is practically undisturbed. The "scraping" action would be much less effective if waves are rippling around on the surface - you have just a tiny fraction of a second to collect all the vapor you're going to get. Of course, any baffling that protrudes up through the surface will interfere with the smooth scraping action as well.

If you want to try a "jam jar" that works well lying on its side, find a smallish bottle with the flattest sides you can find, again so you can get a very shallow unbroken pool. Something like a typical steak sauce bottle might make a good try at this.

But, this is speculation. I've only actually run them a few times, and my little jars were quite conventional. You're really breaking some new ground here, and it's fascinating to follow your progress.

L Cottrill

PyroJoe
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Post by PyroJoe » Thu Oct 18, 2007 4:21 pm

I've tried varied wire types in the pool, just not impressed with any so far. Also varied the height of the pool to just above and just below the surface of the wire/grid.

I get good luck with round bottoms just as often as flat. That was confusing for a time. That four finned banshee runs like a top with a round bottom. It runs so well I have trouble stopping it through all the smoke sometimes. Same with that flattened one. ha

"slosh" isn't a good technical term, I need to hone my tech writing skills. A few years out of practice.

IMO there is a condition needed for creating fuel vapor.
I think that the pool has to be splashed so that a certain amount of liquid spreads over a volume of surface area on the sides of a jar. The bulk of the liquid will flow back to the pool. this deposits a thin film that turns to vapor in a short amount of time. This is in addition to the vapor forming on the surface of the pool. The process has an advantage after about 15 sec. of running, as the pool heats up, as well as the sides.

I think there is a balance of the pool surface area vs. how mush "splash vapor" is created.

Run rich/Run lean variables.

I do agree that the bulk of the pool needs to stay at a certain distance from the opening.
-----------UPDATE 1/22/08: Not sure the pool needs to stay at any certain distance from the opening. Observed from the side running jars.-------
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Mark
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Odd metal jars

Post by Mark » Thu Oct 18, 2007 11:15 pm

Perhaps many of you have noticed how sensitive some jam jars are if you just jiggle them a little bit, just a quiver of your hand will often instantly stop them if you hold them in your hand. And if you have some peppy fresh methanol on a cool day, the combustion can really rev and flameout your jar if you put just a little too much alcohol in it, there's too much splash which either dampens resonance or makes the fueling too rich. Isn't it funny how if you don't wipe the top of the lid after shaking the jar, that that little bit of alcohol will also kill an otherwise ready to start jar? That caution is even mentioned in Reynst's literature.
But I have noticed too on my tall quilted crystal jam jar, it is more forgiving if you put in more alcohol than you need. Either the flame front can't attack/blast the pool of alcohol as strongly or just the relative distance from the hole in the lid to the bottom is great enough that whatever gets jostled and thrown about isn't as critical.
I have a large chrome-plated syringe that I put a few ounces of methanol in and ran it submerged up to its neck in water in a gallon coffee can, with an aluminum pie pan skirt around the neck and a gentle drawing away/sucking breeze from a fan to keep the steam that formed from getting ingested and choking the syringe jam jar into stopping. It ran for a little over 6 minutes if I recall, and you can imagine that is a lot of alcohol for a little jam jar syringe to hold, so it too tolerated the greater fuel. Again, this syringe had a long proportion to it, but if you get too tall for your width, of course the engine can't feed and it won't run from that extreme either.
I have found that sometimes a convex or concave bottom can affect your jar negatively. And if you put things in the jar you have to be careful too, even little structures on the bottom can detract from your goal.
My 2.5 gallon snorkeler is a little fussy if you have a few liters in the bottom, but once it catches and runs for 10 or so seconds it usually will run all the fuel out of the tank, glowing red hot. Imagine how that methanol must be boiling in there then.
I found that a thick flat lid can also defeat you. Some dampening is going on there too that just doesn't swirl/twist the air the same as a thin jar lid. There are not many absolutes, often there is an exception.
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Odd jam jar

Post by Mark » Thu Oct 18, 2007 11:44 pm

Here's a silly jam jar made of carbon. It is a crucible with tiny jam jar lid. The crucible is a little over 6 inches tall. It didn't run all that well but graphite conducts heat I found out. ha
Mark

PS
Probably these would be better, my crucible is a little porous.
http://tinyurl.com/2z4a69
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Mark
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Odd jam jar

Post by Mark » Fri Oct 19, 2007 12:51 pm

One thing about carbon/graphite jam jars though on the plus side is that you can pour molten gold in them and they aren't going to be shocked and crack from thermal expansion. Also, the last time I checked it had the highest melting point of any element. ha
That makes it a good choice for a jam jar in some respects.

And now for some gray areas.

"The chemical element with the highest melting point is tungsten, at 3695 K (3422 °C, 6192 °F) making it excellent for use as filaments in light bulbs. The often-cited carbon does not melt at ambient pressure but sublimates at about 4000 K; a liquid phase only exists above pressures of 10 MPa and estimated 4300–4700 K."
http://en.wikipedia.org/wiki/Melting_point

"Moreover, carbon has the highest melting/sublimation point of all elements. At atmospheric pressure it has no actual melting point as its triple point is at 10 MPa (100 bar) so it sublimates above 4000 K. Thus it remains solid at higher temperatures than the highest melting point metals like tungsten or rhenium, irrespective of its allotropic form."
http://en.wikipedia.org/wiki/Carbon
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PyroJoe
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Post by PyroJoe » Fri Oct 19, 2007 1:25 pm

Here is the flat one running.
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PyroJoe
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Post by PyroJoe » Fri Oct 19, 2007 1:55 pm

"Perhaps many of you have noticed how sensitive some jam jars are if you just jiggle them a little bit, just a quiver of your hand will often instantly stop them if you hold them in your hand. And if you have some peppy fresh methanol on a cool day, the combustion can really rev and flameout your jar if you put just a little too much alcohol in it, there's too much splash which either dampens resonance or makes the fueling too rich. Isn't it funny how if you don't wipe the top of the lid after shaking the jar, that that little bit of alcohol will also kill an otherwise ready to start jar? That caution is even mentioned in Reynst's literature.
But I have noticed too on my tall quilted crystal jam jar, it is more forgiving if you put in more alcohol than you need. Either the flame front can't attack/blast the pool of alcohol as strongly or just the relative distance from the hole in the lid to the bottom is great enough that whatever gets jostled and thrown about isn't as critical."

Mark explains it well. I often will hammer out a convex or concave bottom if it is drastic.

The "peppy fresh" description is spot on also. I often will have to try 3-4 times with fresh fuel before the vapor rate tapers to a useful level.

The ones shown above are more forgiving with the alcohol around the opening. They will start with the opening entirely wet with alcohol. They often will not start unless the inside of the pipe is damp with the methanol.

The short pieces of pipe allow more freedom of design, and some built in "forgiveness". That added to the "tall skinny" type is almost like cheating. ha

PyroJoe
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Post by PyroJoe » Fri Oct 19, 2007 4:42 pm

I wanted to understand the temperature properties of the exhaust gas. I devised a crude test that I call the Charred Toothpick Test.

I had several wooden tooth picks available. (A social requirement here in Texas for some reason)

I placed a tooth pick directly centered, above & touching the four fin exhaust pipe. It charred quickly. I placed another one about 1/4"to 1/2" above the pipe, it charred slower, in about twice the time. I tried one just farther than 1" above, it slowly browned then eventually to black.

I think that puts it close to 536 deg. F. even at 1".
Last edited by PyroJoe on Fri Oct 26, 2007 8:14 pm, edited 1 time in total.

Mark
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In or out or gray area

Post by Mark » Fri Oct 19, 2007 9:35 pm

I know it is said that the flame remains inside a jam jar after the first initial whoosh, but maybe in total darkness there might be a faint flame to be seen just above the hole in the lid. I don't want to rock the boat or anything, but sometimes burning methanol is kind of hard to see. Maybe an odd shaped jam jar would do something different too. I just hate to say anything definitive without first hand knowledge.
I know with my 2.5 gallon snorkeler you can't see any fire ejecting out the snorkel in the daytime, but at night it is clearly visible.
Another thing to try would be to hold a little chimney/tubette above your jam jar and in the dark see if you could coax a visible flame to come out and play above and out of the jam jar. There may be gases that are unspent or cooled or diluted or hitting too much turbulence to luminate as they exit. A floating snorkette/tube held an inch or so over the lid might draw the flame out of the jar too.
Anyway, I just wanted to again present my 2.5 gallon piglet snorkeler exhaust, as you can't see any flame in the daytime but the fire becomes quite apparent at night. So to recap, a jam jar may, just may have a tiny little dome of luminous particles being emitted, in total darkness perhaps someone could find/see them. Just a slim chance.
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