WhiteBlaze Pages 2024
A Complete Appalachian Trail Guidebook.
AVAILABLE NOW. $4 for interactive PDF(smartphone version)
Read more here WhiteBlaze Pages Store

Page 2 of 6 FirstFirst 1 2 3 4 5 6 LastLast
Results 21 to 40 of 103
  1. #21
    Registered User
    Join Date
    10-17-2007
    Location
    Michigan
    Age
    64
    Posts
    5,126

    Default

    Quote Originally Posted by Just Bill View Post
    If you happen to know a siding contractor, HVAC, or gutter guy- not sure if it would be too heavy for an aluminum can or be the right shape- but this is the tool they use to do the tapered crimps to fit ductwork or gutters together. The siding guys also carry an assortment of cutters for J channel and F Channel that may be modified.

    http://www.tools-plus.com/malco-c5r.html
    I'll have to poke around at Home Depot (best store for backpacking gear?) and see what I can find.

    I just did an experiment. I simply cut a 1.5" piece off the end of the rubber tube (drinking straw) that came with my Sawyer Mini filter and slipped it over the end of my needle nose pliers. I then crimped the can with the tubing on the inside of the can and a 1.5" 4d finishing nail on the other side. It worked pretty well. I got nice consistent crimps. They also seemed to be a bit different shape than the ones I get by hand. The dent made by the nail is narrower than the ones I have made previously. I finished the stove (16 ribs) but have not drilled it yet. I thought I might see if I can finds an pin vice drill with a 0.6 mm bit from the hobby shop tomorrow.

  2. #22
    Registered User
    Join Date
    10-17-2007
    Location
    Michigan
    Age
    64
    Posts
    5,126

    Default

    Over on this thread there is a video of the Toaks titanium "capillary" stove. I had not seen that in action before.

    http://www.whiteblaze.net/forum/show...=1#post2016375

  3. #23

    Default

    Looks like my CHS! (Big yellow flames) it's also much heavier than mine.


    Sent from my iPhone using Tapatalk

  4. #24
    Registered User
    Join Date
    12-08-2012
    Location
    Brunswick, Maine
    Age
    62
    Posts
    5,153

    Default

    Quote Originally Posted by Odd Man Out View Post
    I wonder if the cohesion-tension theory of water flow in plant xylem is similar to what you are describing?

    http://science.jrank.org/pages/6949/...on-theory.html

    https://en.wikipedia.org/wiki/Xylem#...tension_theory

    http://www.cropsreview.com/transpiration-pull.html
    I will not pretend to fully comprehend the mechanics of xylem. I do know that it is a marvelous design. While some marvel at its ability to overcome gravity, I marvel at its ability to overcome the limits of atmospheric pressure. It recreates its own head pressure continuously. It is likely my ignorance that keeps me from grasping the similarities to what I would call a metal wick. I do not discount it. I recognize that I am over my head in comparison to present company. I can see similarities to a cloth wick.

    I tend to avoid detailed discussions of mechanics. Some of my views are a bit off the wall. I might as well give an example. I see a similarity between a metal wick and the mpemba effect. Living in Maine, I am all to familiar with this phenomenon. As Mainer's acquired running water and then hot water, we learned that the hot water had to run faster than the cold water to avoid having it freeze in our poorly insulated homes. Sometimes I think ice cream makers and hockey players grasp this subject better than scientists. As I type this, I just peeked at Wiki to see the latest theories as to why it happens. It is nice to see convection gaining ground. Funny things happen to water when it is subjected to extreme temperature differences. It is almost as though it is alive. It does not fight subtle temperature differences nearly as hard as radical differences. The ratio is not linear. It is exponential. When a welder welds a pipe that has water in it, they try to seal 4 to 8 as quickly as possible. Steam is not an issue. It is the attack by the moving water that is the enemy. You have to seal it before it gets there. Again, I do not fully grasp the mechanics. I do know it is real. I have enjoyed listening to learned people debate the mpemba effect. Many deny its existence. Sometimes we can understand too much. A similar situation happens with heated metal. It is too easy to blame pressure or capillary action. Something else is happening. The liquid is reacting to the heat. It is attacking it. It is rushing to it. The key to creating a balanced CHS stove it to control that attack. There is a wicking action at the jets. That wicking action provides marginal cooling to the hoop.

    Anyways. I employ my warped may of thinking in my construction methods. If I see something undesirable happening, I think in the above terms and throttle or free accordingly. Achieving balance is so difficult. The tweaks are tiny. I can't tell you how many times I have worked for hours trying to make a good stove and made a mistake that I knew would ruin it. It might be one rib that is too large as the collet is shoved into the bowl. It might be one jet that is too large because I did not drill at the right angle and it has to be adjusted. The stove would work okay. I strive for perfection. I have only made 3 stoves that I am happy with. When a mishap happens, I drop the stove on the ground and crush it under foot... or I finish it and mail it to a friend.
    Last edited by BirdBrain; 11-05-2015 at 01:59. Reason: My ability to spell stinks.
    In the end, it's not the years in your life that count. It's the life in your years. - Abraham Lincoln

  5. #25
    Registered User
    Join Date
    12-08-2012
    Location
    Brunswick, Maine
    Age
    62
    Posts
    5,153

    Default

    Wow! That esoteric gibberish really quenched things. Allow me to dig a bit more. Water is the most marvelous of all liquids. It expands as it freezes. It cannot be compressed. It requires tremendous energy to move from 95° to 100° (Celsius) relative to 90° to 95°. It is a marvelous design. Listen to it at 85°. I heat my water to when it starts to become quiet. Not to when it boils. The noise starts before the battle to change states. It becomes quiet when the struggle is over. Much energy is expended trying to fight the transformation. Much energy is wasted trying to win. It is better to stop the fight before the boil and use 95° water for the freezer bag. An acceptance of reality is useful to us gram weenies. It allows us to carry less fuel. People observe this stuff, marvel at it, and then explain it away. I listen to the explanations and marvel that people cannot see the design. All liquids share some of the abilities of water. The more radical the battle, the greater the fight. Step into water slowly. It is almost like it is not there. Fall 1500' and see what happens. The water fights back. Yes. I know. There is a more palatable way to explain it. I just believe the characteristic is more important than the explanation.

    Einstein wrestled with a thought much of his life. He came to his conclusions after he thought outside the box. At the time, people accepted time as a constant. He picked light as the constant instead. He opined that we are looking at the wrong thing as a constant. My point about a metal wick is that we are looking at the wrong material when considering the mechanics of a CHS. A white box stove boils its fuel and the vapors are forced out the jets via pressure. That stove relies on internal feedback to run. If you pour fuel into a CHS stove it will just sit there. Metal is not fibrous. Heat it a bit and the fuel, not just vapors, wick up the walls. Having welded, brazed, and sweat pipe, I expect this phenomenon. ADB shared a video with me recently. I am sure I have dug deep enough. I will post it as food for thought and just close by saying when we look at how to tweak a CHS, look at the right material.


    https://www.youtube.com/watch?v=SV0jNlNwUlo

    Another thought and I really must wade into shallower water. Pressure is not a good thing in a CHS. You want balance, not pressure. The wick is enough. TetKoba demonstrates this with this video. If you seek to deliver fuel via pressure, you will have a "bubble bomb" stove. Seek to balance it instead.


    https://www.youtube.com/watch?v=hdYHrX2KydY



    Last edited by BirdBrain; 11-05-2015 at 11:26.
    In the end, it's not the years in your life that count. It's the life in your years. - Abraham Lincoln

  6. #26
    Registered User Just Bill's Avatar
    Join Date
    07-06-2013
    Location
    Chicago, Il
    Age
    45
    Posts
    3,770

    Default

    Quote Originally Posted by Odd Man Out View Post
    I'll have to poke around at Home Depot (best store for backpacking gear?) and see what I can find.

    I just did an experiment. I simply cut a 1.5" piece off the end of the rubber tube (drinking straw) that came with my Sawyer Mini filter and slipped it over the end of my needle nose pliers. I then crimped the can with the tubing on the inside of the can and a 1.5" 4d finishing nail on the other side. It worked pretty well. I got nice consistent crimps. They also seemed to be a bit different shape than the ones I get by hand. The dent made by the nail is narrower than the ones I have made previously. I finished the stove (16 ribs) but have not drilled it yet. I thought I might see if I can finds an pin vice drill with a 0.6 mm bit from the hobby shop tomorrow.
    Might be too big, but in that type of rig (or in a channel pliers to get some distance between the faces of the pliers) a cut nail (sometimes called concrete nails) might be a good shape to work with that mimics the architectural ruler typically used. http://www.bobvila.com/articles/446-.../#.Vjt4OLerRQI

    Of course a #2 pencil or dowel rod could be sanded a bit too to create the exact shape you need. Oak is plenty strong enough to bend aluminum cans and you could make a male and female side and put in in some pliers for perfect repeats.

    Otherwise... I fully support mad tinkering but opted out of alchy street last year.
    The toaks looks mildly interesting only in that I can pick it up off the shelf and this design appears to solve the cold weather issues...

  7. #27
    Registered User Just Bill's Avatar
    Join Date
    07-06-2013
    Location
    Chicago, Il
    Age
    45
    Posts
    3,770

    Default

    One other thing as long as the experts are opining (not to step on your eloquence there BB as I enjoyed it)

    But a practical question...
    One thing I dislike about the alchy stove is the pot stand.
    I do like the Olicamp XTS pot with the heat exchanger that OMO also favors.
    The off the shelf toaks is interesting.

    So would a Caldera Cone (Custom one with the right height), Olicamp pot, and this style of stove be a good combo?

    One thing I like about the TI Caldera Cone is that I can scrape up some fading coals and set a pot on for an evening tea without rebuilding the fire.
    I've been a bit hesitant to do that with the XTS pot as I didn't want to gunk up the heat exchanger with debris... a CC would let me use that pot for that purpose.

    They are all lighter options than an empty canister... at like many here I have looked at my pile of empty fuel cells before and wasn't happy with the waste.

  8. #28
    Registered User
    Join Date
    12-08-2012
    Location
    Brunswick, Maine
    Age
    62
    Posts
    5,153

    Default

    Quote Originally Posted by Just Bill View Post
    One other thing as long as the experts are opining (not to step on your eloquence there BB as I enjoyed it)

    But a practical question...
    One thing I dislike about the alchy stove is the pot stand.
    I do like the Olicamp XTS pot with the heat exchanger that OMO also favors.
    The off the shelf toaks is interesting.

    So would a Caldera Cone (Custom one with the right height), Olicamp pot, and this style of stove be a good combo?

    One thing I like about the TI Caldera Cone is that I can scrape up some fading coals and set a pot on for an evening tea without rebuilding the fire.
    I've been a bit hesitant to do that with the XTS pot as I didn't want to gunk up the heat exchanger with debris... a CC would let me use that pot for that purpose.

    They are all lighter options than an empty canister... at like many here I have looked at my pile of empty fuel cells before and wasn't happy with the waste.
    Yes. It would make a great system. Titanium is an insulator (compared to aluminum). If you have a two piece construction, you can store the cone in the pot. I suspect there would have to be some experimenting to determine the correct top of stove to bottom of pot distance. A heat exchanger changes the airflow. It is likely the distance would have to be greater than when using a grease pot. I do not use a pot stand. I have built a few for others, including the one below. My old system is pictured at the bottom. It stores in my grease pot.
    Attached Images Attached Images
    Last edited by BirdBrain; 11-05-2015 at 12:16.
    In the end, it's not the years in your life that count. It's the life in your years. - Abraham Lincoln

  9. #29
    Registered User Just Bill's Avatar
    Join Date
    07-06-2013
    Location
    Chicago, Il
    Age
    45
    Posts
    3,770

    Default

    Thanks...
    SO how many cc's of alcohol to boil a bowling ball?

    I'd probably one piece the cone and store elsewhere... and it sounds like that TI version could simply be set right on the ground (or compacted snow) regardless of temps with that design? I won't pretend to understand half of the discussion but the bit I get seems to indicate that is the case.

    Yellowish flame from the toaks demo videos simply indicates some dirty fuel right? Not any issues with the design?

  10. #30

    Default

    BB I was looking for numbers for thermal diffusivity of Ti vs Al. And alloys. Do you know if there is much variation between pure and alloyed Ti and Al? I was able to dig up some data for various Ti alloys after a bit of searching, but have yet to compute thermal diffusivity from density, heat capacity and thermal conductivity and compare to aluminum.


    Sent from my iPhone using Tapatalk

  11. #31
    Registered User
    Join Date
    10-17-2007
    Location
    Michigan
    Age
    64
    Posts
    5,126

    Default

    I would think a cone with an Olicamp stove unnecessary. I don't really have much heat coming out through the heat exchangers so I don't think using a cone to capture extra heat is an advantage. Of course I haven't used it over camp fire coals, so for that application may be useful, but that is a special case.

    My most recent modification was to switch from using a hardware cloth pot stand with an aluminum flashing wind screen that came up the side of the pot to a combination aluminum flashing wind screen/pot stand. The new wind screen/pot stand does not have vents on the top so all the heat is forced through the heat exchangers. This gave a measurable increase of power (shorter burn times) and efficiency (less fuel needed). I presume that in the old system, some heat bypassed the heat exchangers in which case having the wind screen come up the side (or a cone) would help. The new system has three advantages. There is one less part (no separate pot stand needed). It's lighter (the wind screen is much smaller and there is no pot stand). More convenient to use (the assembled wind screen stores in the pot so no need to assemble/disassemble for each use). It is possible that this system is more susceptible to wind since there is no screen shielding the side of the heat exchangers, but my gut tells me this shouldn't be a problem. When I retire I will build a wind tunnel and test the effects of wind on various stove systems. I'm fairly certain this is one key parameter that has never been subject to rigorous independent testing.

  12. #32
    Registered User
    Join Date
    10-17-2007
    Location
    Michigan
    Age
    64
    Posts
    5,126

    Default

    And here is the spiffy graphic of the old system and my recent modification

    stove.gif

  13. #33
    Registered User
    Join Date
    12-08-2012
    Location
    Brunswick, Maine
    Age
    62
    Posts
    5,153

    Default

    Quote Originally Posted by aero-hiker View Post
    BB I was looking for numbers for thermal diffusivity of Ti vs Al. And alloys. Do you know if there is much variation between pure and alloyed Ti and Al? I was able to dig up some data for various Ti alloys after a bit of searching, but have yet to compute thermal diffusivity from density, heat capacity and thermal conductivity and compare to aluminum.


    Sent from my iPhone using Tapatalk
    There is a variance across the grades. However, when aluminum transfers heat 10 times better than titanium (on average), the slight variances between the grades become unimportant. Quite frankly, the hot spot on a ti pot is overcome by the convection in the water. The heat is transferred somewhat equally. Small differences in grades are unimportant when huge differences in materials do not show visible differences in performance. It is better to concentrate on other properties. As an example, the tops of an aluminum can is made of a harder grade of aluminum that the body of the can. The harder grade is used to allow the pop top to function better. This difference in grade is important to a stove builder because the harder aluminum does not degrade as quickly as the softer alloy when they are subjected to the same heat. When it comes to titanium, the ability to retain shape will be more important than its heat transfer properties. I do not tinker with titanium. Therefore, I cannot advise beyond the abstract thought that it would make a better cone than aluminum. That and a trowel is the only way I would own titanium anything.
    In the end, it's not the years in your life that count. It's the life in your years. - Abraham Lincoln

  14. #34
    Registered User
    Join Date
    12-08-2012
    Location
    Brunswick, Maine
    Age
    62
    Posts
    5,153

    Default

    Quote Originally Posted by Odd Man Out View Post
    And here is the spiffy graphic of the old system and my recent modification

    stove.gif
    Oh my! I can see many grams of base weight savings there. Very nice. Very simple. Very practical. You are making me more and more jealous of your pot.

    My goodness, I love this innovation. I am tempted to crumple my cone and buy an Olicamp now. I was never tempted with your previous shield, stand combo. I anxiously await real world testing on the new setup.
    Last edited by BirdBrain; 11-05-2015 at 13:07.
    In the end, it's not the years in your life that count. It's the life in your years. - Abraham Lincoln

  15. #35
    Registered User Just Bill's Avatar
    Join Date
    07-06-2013
    Location
    Chicago, Il
    Age
    45
    Posts
    3,770

    Default

    Quote Originally Posted by BirdBrain View Post
    Oh my! I can see many grams of base weight savings there. Very nice. Very simple. Very practical. You are making me more and more jealous of your pot.


    Indeed!
    All the cone does is recapture the lost heat you've shown in the original set up...
    With the heat exchanger doing that job much better than a cone ever could (and the slightly lower heat output and spillover in Alchy vs. cannister fuel) your second design is ideal.

    Does double duty in solving the need for a tall cone and storage solution or split cone design to store in the pot too.

    Triple duty in cutting out parts and pieces.

    To keep you on the trail in retirement... ground wind even in a very windy situation is easy enough to deal with for the most part. Simply sitting down in front of the stove or laying your pack there does 95% of the work IMO.

    That said- I'd think a double wall stand (or a corrugated shape ideally I suppose) would likely do the rest of the job? You fellas have all kinds of experience with that sorta construction at this point... I'm guessing a Heinie can would be roughly the right size and a liner with a crease or four to keep the walls separated evenly would do it. Or a thin skin of 1/8" foam with spray adhesive (I believe temps are low enough) would be even better?

    Much like my sleeping pad in a hammock debate... one thin layer of trapped air would prevent most of the convection heat stripping of the wind inside the "combustion chamber" of the stand. You would have little turbulance at the intakes on the ground, and the shape of the heat exchanger should minimize or eliminate any significant loss at the top.

    VERY NICE either way...

    PS- on the campfire deal... your stand would still work. Essentially (in my case especially) the heat source of the fire is unlimited so the cone isn't for efficiency. It's just there too keep the heat exchanger out of the coals. I don't use that pot with my esbit stove for the same reason... I can't imagine how little fun that thing would be to clean out when the time came so the only purpose is to stop the heat exchanger from getting all gunked up.

  16. #36
    Registered User Just Bill's Avatar
    Join Date
    07-06-2013
    Location
    Chicago, Il
    Age
    45
    Posts
    3,770

    Default

    olicamp screen.jpg
    I'm thinking something like this... do the outer layer just a hair bigger than the stove itself and make it tall enough so it overlapped the closed part of the heat exchanger so the pot can slide off the stand when cooking. The inner would be whatever height you're doing now with 4-8 creases as needed and would bear the actual pot with very high stability (one thing i don't like about non-cone screens is the stability).

    Offset intake holes in the layers to prevent direct wind? A little aluminum bug screen on the pot itself would further slow/bust turbulence if you wanted to go nuts.

  17. #37

    Default

    BB: I was asking about Ti vs Al for usage as pots and wind-screens. I'll stick to my aluminum cans for stove construction. I'll pull some random numbers for alloys and see what thermal diffusivities I come up with. I'm not worried about heat flowing in the plain of the thin shell making up the pot, but rather across it, and into the water. (You're right, convection is very efficient heat transfer, so I'm not worried about a hot spot in the bottom center.) The higher the thermal diffusivity of the pot material, the more efficient the stove should be. If you're right (I'm not questioning this, I just want to look at the numbers myself) that Al has a higher thermal diffusivity than Ti then maybe I'll have to look into buying a walmart grease pot. I'm guessing it will be cheaper than something titanium... as long as the weights are comparable...

    OMO: I would be curious to hear the fuel difference for a boil test between your two setups.

    JustBill: I'm getting my PhD studying turbulence, and you are completely correct, a screen is great for getting rid of large-scale turbulence. They actually generate turbulence, but at very small scales. These scales dissipate quickly, and also would probably help enhance the efficiency of the stove if they were to stick around, since they could help enhance mixing of the fuel jets with the air. Across a screen there is a pressure drop too, so you also get some gust protection. In fact, subsonic wind tunnels often use screens upstream of the test section to help condition the flow and reduce the free-stream turbulence levels.

  18. #38

    Default

    BB, one more quick question: Is this the pot you use? If not do you have a link? http://www.walmart.com/ip/STANCO-GS1...ingMethod=p13n

  19. #39
    Registered User Just Bill's Avatar
    Join Date
    07-06-2013
    Location
    Chicago, Il
    Age
    45
    Posts
    3,770

    Default

    Would there be an advantage to putting the intake holes high on the outer layer of a double walled stand, and low on the inner wall?
    So you'd have a heat exchanger effect and totally knock out intake turbulence.
    Is there any efficiency advantage in providing heated (or at least warmer air) to the stove?

    Or are we talking PHD laboratory levels of precision here to measure the results.

  20. #40

    Default

    Quote Originally Posted by Just Bill View Post
    Would there be an advantage to putting the intake holes high on the outer layer of a double walled stand, and low on the inner wall?
    So you'd have a heat exchanger effect and totally knock out intake turbulence.
    Is there any efficiency advantage in providing heated (or at least warmer air) to the stove?

    Or are we talking PHD laboratory levels of precision here to measure the results.
    haha, well, I like your thinking about the heat exchanger to pre-heat the air provided to the stove with heat that would otherwise be wasted to the environment. You will certainly get an increase in efficiency *if* you can pull it off, but how much it will improve the efficiency would be hard to say--it could be completely negligible. My bigger concern is weight of the pot-stand/windscreen as well as choking the stove. If it's not windy out, and your heat exchanger does work, then the denser cold air will be stacked on top of the less dense, lighter air. This could make the air in this vertical heat exchanger want to reverse directions due to buoyancy. However, I would guess that there would be a large enough low pressure at the base of the stove, driven by the entrainment of air into the much hotter, more buoyant flame, and then out the exhaust/top of the system. If I had to guess, I would say you're probably better off with a simpler wind shield, or some foam insulation on the outside of it, but I could be wrong.

Page 2 of 6 FirstFirst 1 2 3 4 5 6 LastLast
++ New Posts ++

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •