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View Full Version : Aluminum or Titanium, fuel weight



SamIam
2006-04-13, 15:37
I have always wondered about the benefits of titanium cookeware. It is touted as the primo lightweight cookware, yet it is a denser material then aluminum (heavier for the the same size), and much worse at heat conductivity. Thus heavier to carry, and more wastefull to heat.

Based on the numbers below, it looks like aluminum conducts heat 10.8 times better then titanium, and is 0.6 times as heavy. If cost is not a factor Titanium is a reasonable tradeoff with stainless steel. It has similar durability, better heat transimission, and lower weight.

If however you are concerned with grams of fuel and grams of cookware, then alumimum is almost half as heavy, and more then ten times as good at heat conduction. I am assuming that higher heat conductivity allows water to be boiled with less fuel use. Aluminum is also super super cheap compared with titanium. . . . . . .

Soooo maybe the perfect cook pot has aluminum bottom and walls, and a titanium lid (a really thin lid)?

Naturally, all of this is moot ("mute" as my wresling coach used to say) if you are allergic to aluminum.

Whatchall think?

Titanium
Thermal conductivity 21.9 W/(m*K)
Density,Hardness 4507 kg/m3, 6

Aluminum
Thermal Conductivity: 237 W/(m*K)
Density, Hardness 2700 kg/m3, 2.75


Stainless Steel:
Thermal Conductivity: 14 W/(m*K)
Density 8000 kg/m3

http://hypertextbook.com/physics/thermal/conduction/
http://academickids.com/encyclopedia/a/al/aluminium.html

Seeker
2006-04-13, 16:27
i'm not the technician on this site, but there are a few who will be able to argue with your 'facts' if they aren't correct... i'll assume they are because i don't know better... and i hope what i just said doesn't come across as anything but pleasant... i don't mean to imply anything... just saying i can't argue with your figures...

i have used the walmart grease pot for it's light weight. i don't like that i had to trim its weird lip, that there's no bail, and that it's really weak. but it's just about the right size and weight for me. i can even cook for two in it. cleanup is a pain though, and i'm a little worried about the alleged aluminum/alzheimer's link.

i also have an MSR Titan kettle. it's smaller, the same weight as the grease pot, i've never noticed a difference in heating time to boil my dinner up, and i like how strong the little sucker is... clean up is simple, and i can use sand from a creek bottom to scour it with no loss o material. can't do that so well with my grease pot.

all that said, you may be on to something... how about a steel-lined aluminum pot? in a 1liter size please...

SamIam
2006-04-13, 19:18
Well, I was really fishing (spin fishing, I dont have a boat to troll with ;-) to see if i could catch someone interested enough to do some testing. I was hoping maybe I could provide a new source of entertainment for someone who likes to measure fuel consumtion vs container weight vs marginal weight carried per mile per trip etc.. . . hehehehe

Yes, truly, the numbers may matter for a car radiator, but not be of practical value in a cooking situation (for whatever reason). Your solution might give the best heating efficiency/durrability/cost compromise, AND protect you from eating aluminum, yay!!

Seeker
2006-04-14, 00:39
ah... a self proclaimed troll... well, thanks... that's honest at least... :biggrin:

but you're a little late... sg rock would be the "someone" who'd be interested... he's already done the fuel weight test thing... alcohol is best up to 14 days... after that, canister stove, then white gas... that's assuming one hot meal per day... but he's away for a bit... might be someone else who's done the work figuring out the aluminum/titanium/steel thing, but it think the real issue with most folks here is function... whatever gets the job done, and is lightest, is often the most popular... not always, but usually... there are some holdouts (Iceman! :biggrin: ) who insist on having things like electricity, running water, and a sink... but as long as he can carry it in his sled, he's happy... and as long as i don't have to carry it, i'm happy... so we get along just fine...

Iceman
2006-04-14, 01:21
Hey, I resemble that remark! :biggrin:

SamIam, I like your thought, and your approach! Good points. I own a couple of items in alum, and a couple in Ti. I like the titanium better, tougher than nails. No straightening out your stuff when you pull it out of the stuff sack. And like Seeker said, I am not a lightweight nut. (In practice, or reality)

I guess it really depends on the aluminum too. One of the light weight alum pots I own is so flimsy, I could crush it like a been can. Cheap. Light, but too cheap. Another alum pot is a bit more durable. My alum pots have warped on the bottom from too much heat. Not so with the titanium.

Anyway, Welcome!

Kea
2006-04-14, 01:32
there are some holdouts (Iceman! :biggrin: ) who insist on having things like electricity, running water, and a sink... but as long as he can carry it in his sled, he's happy... and as long as i don't have to carry it, i'm happy... so we get along just fine...

Obviously, you guys never heard about the wood fired hot water heaters that I've built. :)

When Kea wants creature comforts in non-home settings, she's hardcore about engineering! The Army Corps of Enginneers' only advantage is power tools and earth moving equipment.
:biggrin:

dropkick
2006-04-14, 02:12
Obviously, you guys never heard about the wood fired hot water heaters that I've built. :)
I'm sure Iceman would interested in your water heater as I'm sure he's tired of having to heat all those pots of water to fill his bath tub. :rolleyes:

blackdog
2006-04-14, 02:40
...all that said, you may be on to something... how about a steel-lined aluminum pot? in a 1liter size please...
Trangia has one. You're looking for a Duossal pot. :)

DUO SS AL is two materials in one, pressed together. Aluminum on the outside and stainless steel on the inside. Duossal pans are both durable and quick to heat up.

Seeker
2006-04-14, 12:47
thanks... i've heard of it, but never seriously looked at it... i will now!

Lanthar
2006-04-14, 17:57
The whole aluminum being more efficient to cook with thing has been debunked (http://www.thru-hiker.com/articles.asp?subcat=2&cid=36) numerous times.

The reality is, with the thiness of the material that we are talking about, there are FAR more meaningful dynamics in play for the type of cookware you're talking about (at least for any engineer who actually paid attention in heat transfer class). Remember, for similar durability, titanium is going to be MUCH thinner (read much less thermal resistance as thermal resistance is a product IIRC of thickness squared)... things like residence time of the hot gases against the pot, reduction of wind-based (convective) heat transfer... have far more impact than choice of pot materials... now... of course if you don't care about durability (and there are all sorts of arguements on how much durability is actually needed) make a pot out of foil (http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/1277/index.html)

Lanthar
2006-04-14, 17:59
The whole aluminum being more efficient to cook with thing has been debunked (http://www.thru-hiker.com/articles.asp?subcat=2&cid=36) numerous times.

The reality is, with the application you are talking about, there are FAR more meaningful dynamics in play for the type of cookware you're talking about (at least for any engineer who actually paid attention in heat transfer class). Remember, for similar durability, titanium is going to be MUCH thinner (read much less thermal resistance as thermal resistance is a product IIRC of thickness... possibly squared... it's been a while since I've looked it up)... things like residence time of the hot gases against the pot, reduction of wind-based (convective) heat transfer... have far more impact than choice of pot materials... now... of course if you don't care about durability (and there are all sorts of arguements on how much durability is actually needed) make a pot out of foil (http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/1277/index.html)

Seeker
2006-04-15, 13:31
Ah! Lanthar! there you are... SamIAm, meet one of our resident technicians... i wondered when you'd be here... thanks for coming... i have no patience with tech data... you seem to thrive on it, and i'm glad to have you around to translate for me... :biggrin:

KLeth
2006-04-15, 13:59
I love my Trangia Ti pots - Switched to them from the Trangia Doussal pots and saved 500g and I don't have a noticable increase in fuel-consumption.
When cooking other stuff than water we can see that the food burns more easily in the Ti pots.

Lanthar - You saved me a long explanation! - I support your statement.

Lanthar
2006-04-15, 14:13
Ah! Lanthar! there you are... SamIAm, meet one of our resident technicians... i wondered when you'd be here... thanks for coming... i have no patience with tech data... you seem to thrive on it, and i'm glad to have you around to translate for me... :biggrin:

:biggrin: Glad to be of service... Things have been hectic, and are about to get more hectic (My wife was due yestereday, so we're playing the 'walk a lot and eat spicy food and wait' game to encourage our first child to leave his nice comfy living quarters)

Just wait until I prove my theory that you can (others don't believe me, but it all has to do with my 'you burn cozies because you have too high of a burn rate and too many BTUs are escaping up the side of the pots rather than getting into the water' theory) boil water in a cozied pot (and maybe even a heinie can)... ;) at least if I get some time this summer, that's what I plan to do...

(It helps that I've found some promising materials...)

SamIam
2006-05-02, 23:01
ah ha,

what i take away from this is that the actual configuration of the cooking vessel may have a larger impact on heat transfer then the material choice. I think thermal resistance has a linear relationship to thickness, and stiffness an exponential one. . . . T4 aluminum is stronger then steel, but I dont think cookware is made out of it.

Perhaps an ideal configuration would be to turn the cookpot into a kind of chimmney for the cookstoves hot gases? I have seen heat exchanger fin type thingies that fit over a cookpot like a cozie. Maybe constructing one to guide the hot gas in spiral around the pot. Of course, the weight of such a thing may be prohibitive when compared to fuel savings. Assuming weight is what you care about. Aspestos cozie?

You might be able to increase hot gas residence time by putting a rim around the base of the cook pot, trapping a bubble of combusion gas against the bottom, or maybe instead of heat exchanger fin things, you just make it a double walled pot with the bottom open. THis might have the effect of giving the pot a hot blanket. Of course two walls doubles your weight, unless you can use it structurally. Presumably turbulence is going to trump any convection.

oops56
2006-05-02, 23:59
Well i think we need to do away with the windscreen. Have a stove small burns better with a breeze or wind more wind the hotter the fire lets make one some how but good also no wind

Lanthar
2006-05-03, 17:46
You might be able to increase hot gas residence time by putting a rim around the base of the cook pot, trapping a bubble of combusion gas against the bottom, or maybe instead of heat exchanger fin things, you just make it a double walled pot with the bottom open. THis might have the effect of giving the pot a hot blanket. Of course two walls doubles your weight, unless you can use it structurally. Presumably turbulence is going to trump any convection.

Wow... someone thinks the way I do... seriously, I've had similar thought for planning my DIY mods for pots... focus on trapping the combusted gases against the pot for as long as possible...

SGT Rock
2006-05-12, 04:37
Reading through the thread, I have some thoughts to add.


Based on the numbers below, it looks like aluminum conducts heat 10.8 times better then titanium, and is 0.6 times as heavy. If cost is not a factor Titanium is a reasonable tradeoff with stainless steel. It has similar durability, better heat transimission, and lower weight.

These numbers are for pure titanium. But the grade of titanium used in applications such as cooking pots is 6AL4V which is an aluminum titanium alloy that is really MOSTLY aluminum. So your numbers reference to density and conductivity are off. I don't pretend to know how to calculate this exactly or say what difference that actually makes. I just know in my experience that there doesn't seem to be much difference between Ti pots and Aluminum pots in how well they conduct heat.


Perhaps an ideal configuration would be to turn the cookpot into a kind of chimmney for the cookstoves hot gases? I have seen heat exchanger fin type thingies that fit over a cookpot like a cozie. Maybe constructing one to guide the hot gas in spiral around the pot. Of course, the weight of such a thing may be prohibitive when compared to fuel savings. Assuming weight is what you care about. Aspestos cozie?

You might be able to increase hot gas residence time by putting a rim around the base of the cook pot, trapping a bubble of combusion gas against the bottom, or maybe instead of heat exchanger fin things, you just make it a double walled pot with the bottom open. THis might have the effect of giving the pot a hot blanket. Of course two walls doubles your weight, unless you can use it structurally. Presumably turbulence is going to trump any convection.

I agree with the statement about cookpot chimney. There is even a type of system that does this called the Kelly Kettle: http://www.kellykettle.com/ which is probably the best design to take advantage of this sort of cooking. Here is an evaluation of it: http://www.oldjimbo.com/survival/kellystove.html which shows how this type of pot is basically your stove and kettle all in one. The mini Kettle weighs in at .445 KG and can heat 580ml of water using wood. I assume one could take off the bottom pan and replace that with whatever stove they wanted. The only draw back is needing another container for your food to eat out of. But think of replacing your 6 ounce pot and 2 ounce stove system with a 16 ounce stove and a 1.5 ounce plastic bowl with cozy.I just wish they could make one in titanium LOL. Maybe someone could take one and replace the bottom with a titanium cup for a few grams of weight savings, but probably not worth it.

I tried using aramid cloth once to make a cozy you could have on the pot when it was burning - didn't work out so well.

I tried the rim around the bottom idea. Basically made an aluminum collar that fit on the bottom of the pot so it created that space. What I found was it didn't work so well. What it appeared to do was force the gas back down to the edge of the ring where it then combusted. Maybe if the height of the pot were higher so that the combustion occurred lower and then the ring trapped some heat under the pot? But anyway, it seemed what I really needed was more of a "Chimney" around the pot that trapped heat around the bottom and sides of the pot while also ensuring proper combustion inside - this meant you really do need air flow that allows the hot air to eventually escape on or near the top of the pot somehow. After thinking about that, I realized that is basically what the windscreen is already doing. The only way to increase efficiency would be to make the outside of the windscreen insulated.


Well i think we need to do away with the windscreen. Have a stove small burns better with a breeze or wind more wind the hotter the fire lets make one some how but good also no wind
Well this is why a good windscreen has some holes at the bottom - to let in some of that wind. But burning hotter doesn't always mean more efficiently. I like to make my windscreen with holes only on one side so I can adjust how they face into the wind so I can also adjust how much air flow goes into the stove.