A lot of UL folk tend to use titanium cookware coz of its light weight and maybe ease of cleaning.
But because titanium is such a poor heat conductor compared to aluminium don't you tend to use and therefore carry more fuel, thus losing any weight gain from the cookware ?
Registered: 09/07/04
Posts: 172
Loc: Washington DC area
I don't know about weight from fuel.... I always carry aluminum cookware. It's cheap and it cooks really well, particularly for cooking eggs and hash browns in the morning it works so much better than Ti for actual cooking that it's worth it. Al is pretty light stuff, I can't imagine the weight penalty is significant unless you're seriously anal retentive about weight (admittadly many of us are!).
But because titanium is such a poor heat conductor compared to aluminium don't you tend to use and therefore carry more fuel, thus losing any weight gain from the cookware ?
While that's certainly true, titanium pots are generally thinner than aluminium pots. On the whole, I don't think there's a significant difference.
That said, I use an aluminium pot because it's light enough with excellent dimensions and I haven't come across a titanium pot good enough to justify it's price (here in Finland there's not quite as much to choose from and ordering from the net would be even more expensive).
Ti is a poor heat conductor per mass compared to Al. I use both type of pots. I have not noticed a difference in boil times. This is probably because the Ti pots are thinner than the Al (noted from trae also).
I like Ti better because it’s a little more ding, scratch, and crush resistant than certain Al cook wear.
A lot of UL folk tend to use titanium cookware coz of its light weight and maybe ease of cleaning.
But because titanium is such a poor heat conductor compared to aluminium don't you tend to use and therefore carry more fuel, thus losing any weight gain from the cookware ?
Ti Specific heat: 0.52 J/gK Al Specific heat: 0.90 J/gK
This would seem to indicate that Ti heats up MORE easily than Al. Maybe specific heat isn't the only factor? I'm not sure.
I don't think those numbers are correct. I found a table showing Al having a thermal conductivity of 128-180 W/mC (depending on alloy) and Ti of 15.6, meaning aluminimum conducts heat as much as 11.5x greater than titanium.
The difference is pretty easy to demonstrate in the field. I can pick up a relatively tall uncovered Ti cookpot from the stove w/o using a pot lifter, as the top edge will only be warm, but an aluminum pot will burn the bejezus out of me if I try a similar stunt. Similarly, an aluminum cup of hot coffee or chocolate will burn my lips; titanium is quite comfortable.
In practice, Ti pots are so thin I've never found a measureable difference in boil times comparing similarly sized, covered Al and Ti pots. The net flux seems the same, so I've concluded there's no efficiency difference WRT fuel use. Pot shape, a tight lid and an effective windscreen have far greater effects than pot material.
The biggest difference is Ti pots have much more concentrated hot spots when on the stove, making it much tougher to brown and simmer foods without burning.
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A lot of UL folk tend to use titanium cookware coz of its light weight and maybe ease of cleaning.
But because titanium is such a poor heat conductor compared to aluminium don't you tend to use and therefore carry more fuel, thus losing any weight gain from the cookware ?
Ti Specific heat: 0.52 J/gK Al Specific heat: 0.90 J/gK
This would seem to indicate that Ti heats up MORE easily than Al. Maybe specific heat isn't the only factor? I'm not sure.
Registered: 03/27/04
Posts: 144
Loc: Washington, DC
Complicated problem but just looking at materials properties:
I think there is a confusion of specific heat (the amount of energy to raise the temperature one degree of a hunk of material therefore J/C/kg) and thermal conductivity (how quickly heat moves through a material - W/m/C).
It takes a bit more energy to heat up the Al than it does the Ti - but the heat will be more evenly distributed in the Al. However, it takes much more energy to raise the water by one degree c since: 1.) There is a lot more of it -3 oz pot vs 16oz of h20 2.) the specific heat of water ~4.1/g/c -> more than 4 times more than Al. assuming a 4oz Al pot and a 3oz ti pot with two cups of water (16oz) Al pot: 113g Al*77C*0.9J/g/C = 7858J Ti pot: 85g Ti * 77C *0.5J/g/C = 3272J
Water in the pot: 453g h2o*77*4.1J/g/C = 143200J
So a difference of ~3% more to heat up the Al+h20 vs the Ti+h20. If you are measuring out your fuel within 3% you are spending too much time measuring fuel.
All in all, Al gives more even heating (fewer hotspots), Ti should technically give you a more efficient heating, but these efficiencies are so negligible that it is not even worth trying to compare, pot/stove/windscreen design plays a much more important role by far, but Ti will save you some weight, gain some strength, and loose you more dollars.
Titanium is lighter than aluminum. - just look at how much lighter your wallet is when you use it compared to the guys packing 10 dollar aluminum pots or canpots.
but Ti will save you some weight, gain some strength, and loose you more dollars.
Weight for weight Ti is stronger but most Ti pots are quite a bit thinner than Al pots, so maybe strenght gain is lost ?
I've also heard that if you heat a Ti pot empty, like you can with SS before you put water in them to get a quicker boil going, you can burn holes in the Ti pots or when heating a Ti pan empty without somekind of grease in it for baking could also be troublesome, deforming. Anyone experienced problems like this ? This what i've been told by people who work in outdoor shops.
Probably the thicker AL pots could handle a bit of preheating but a thinner one would probably deform as well ?
The $$ you save with aluminum will pay for your assisted living when you get Alizimers from aluminum contamination!
I think this is still very dubious this claim and hasn't this been cleared a long time ago ? No more use of tin foil in the kitchen then <img src="/forums/images/graemlins/smirk.gif" alt="" />
but Ti will save you some weight, gain some strength, and loose you more dollars.
Weight for weight Ti is stronger but most Ti pots are quite a bit thinner than Al pots, so maybe strenght gain is lost ?
I've also heard that if you heat a Ti pot empty, like you can with SS before you put water in them to get a quicker boil going, you can burn holes in the Ti pots or when heating a Ti pan empty without somekind of grease in it for baking could also be troublesome, deforming. Anyone experienced problems like this ? This what i've been told by people who work in outdoor shops.
Probably the thicker AL pots could handle a bit of preheating but a thinner one would probably deform as well ?
The melting point for Titanium is about 3135F and about 1220F for aluminum.
Registered: 03/27/04
Posts: 144
Loc: Washington, DC
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The melting point for Titanium is about 3135F and about 1220F for aluminum.
Yeah - but they will both burn (oxidize) at temperatures lower than melting in a O2 rich environment. I wouldn't be surprised if the uneven heating in Ti did warp it a bit on excessive heating.
Regarding the higher strength with Ti versus thinner Ti: Ti is about 2x as strong as Al alloy (800+MPa vs 400MPa yeid strength). I'm guessing that the pots are not 2 times thinner. Besides, I'm pretty sure that I could fairly easily bend my Al pot, but I would have to work a lot harder with Ti. Anyone want to donate a SnowPeak mug for science?
I knew all those materials science classes would pay off one day.
I ga-ron-tee you cannot, will not, burn up your titanium pot on any backpacking stove. I've heated mine to an orange glow and yes, it discolors in a kewhl rainbow fashion, but that's it. The metal is so thin that it takes mere seconds for this to occur on a gas stove with a narrow flame. I've learned to put the oil in first.
Ti pots dent and bend much less readily than aluminum of equal weight, which is probably their biggest advantage. Shop the sales and the price isn't all that bad.
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The melting point for Titanium is about 3135F and about 1220F for aluminum.
Yeah - but they will both burn (oxidize) at temperatures lower than melting in a O2 rich environment. I wouldn't be surprised if the uneven heating in Ti did warp it a bit on excessive heating.
Regarding the higher strength with Ti versus thinner Ti: Ti is about 2x as strong as Al alloy (800+MPa vs 400MPa yeid strength). I'm guessing that the pots are not 2 times thinner. Besides, I'm pretty sure that I could fairly easily bend my Al pot, but I would have to work a lot harder with Ti. Anyone want to donate a SnowPeak mug for science?
I knew all those materials science classes would pay off one day.
Registered: 03/27/04
Posts: 144
Loc: Washington, DC
Its got a whole heck of a lot more oxygen than any other atmosphere that I know of. 20% isn't bad. I do know that if you are getting Ti red hot, you are absorbing oxygen into the metallic structure, and in the end, you will make your pot more brittle. Probably not a big enough problem to worry about with a pot though.
Its got a whole heck of a lot more oxygen than any other atmosphere that I know of. 20% isn't bad. I do know that if you are getting Ti red hot, you are absorbing oxygen into the metallic structure, and in the end, you will make your pot more brittle. Probably not a big enough problem to worry about with a pot though.
I'm not really planning on using my Ti pot in other atmospheres. <img src="/forums/images/graemlins/grin.gif" alt="" />
According to this link, Titanium doesn't burn in atmospheres with lower than 35% oxygen. Also, Ti alloys are fairly resistant to oxidation under about 1200F. Link
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Titanium has excellent resistance to gaseous oxygen and air at temperatures up to about 700°F (371°C). At 700°F it acquires a light straw color. Further heating to 800°F (426°C) in air may result in a heavy oxide layer because of increased diffusion of oxygen through the titanium lattice. Above 1200°F (649°C), titanium lacks oxidation resistance and will become brittle. Scale forms rapidly at 1700°F (927°C). Titanium resists atmospheric corrosion. Twenty year ambient temperature tests produced a maximum corrosion rate of 0.0010 mpy (2.54 x 10-5 mm/y) in a marine atmosphere and a similar rate in industrial and rural atmospheres.
Caution should be exercised in using titanium in high oxygen atmospheres. Under some conditions, it may ignite and burn. J.D. Jackson and Associates reported that ignition cannot be induced even at very high pressure when the oxygen content of the environment was less than 35%. However, once the reaction has started, it will propagate in atmospheres with much lower oxygen levels than are needed to start it. Steam as a diluent allowed the reaction to proceed at even lower O2 levels. When a fresh titanium surface is exposed to an oxygen atmosphere, it oxidizes rapidly and exothermically. Rate of oxidation depends on O2 pressure and concentration. When the rate is high enough so that heat is given off faster than it can be conducted away, the surface may begin to melt. The reaction becomes self-sustaining because, above the melting point, the oxides diffuse rapidly into the titanium interior, allowing highly reactive fresh molten titanium to react at the surface.
Titanium burns when heated in air 610 °C (1,130 °F) or higher, forming titanium dioxide.[6] It is also one of the few elements that burns in pure nitrogen gas (it burns at 800 °C or 1,472 °F and forms titanium nitride, which causes embrittlement).[23] Titanium is resistant to dilute sulfuric and hydrochloric acid, along with chlorine gas, chloride solutions, and most organic acids.[2] It is paramagnetic (weakly attracted to magnets) and has fairly low electrical and thermal conductivity.
Registered: 03/27/04
Posts: 144
Loc: Washington, DC
I didn't know about the 35% O2 for burning, thats interesting.
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Further heating to 800°F (426°C) in air may result in a heavy oxide layer because of increased diffusion of oxygen through the titanium lattice. Above 1200°F (649°C), titanium lacks oxidation resistance and will become brittle.
This is what I was referring to above. I'm guessing that a unfilled pot on a pocket rocket could very easily get up to 426C and could get to 650C+ (a propane torch can reach 2000C). Of course the oxidation numbers are not a switch and time exposure has a lot to do with this. But you can do some damage to your pot.
All of this just goes to show, whatever the material (unless its ceramic coated Ni-based superalloy, which would be one heavy, expensive pot, but might make a decent jet turbine blade) don't leave an empty pot on a burner turned on high.
In practice the weight and heat conducting properties are very comparable, considering the Titanium can be thinner. The titanium has a definite edge in heat resistance, but aluminum is fine as long as there is water in it. Both are safe. The Alzheimer Society says that aluminum is not a cause, but you should probably cut down on processed cheese and antacids. Aluminum is probably better environmentally, because it is so abundant, but if you were to buy a titanium pot that you keep for life is probably better environmentally than going through countless aluminum cans because you like to keep experimenting like I do. Biggest issue with Aluminum Beer Can Pots is that they are coated with BPA containing epoxy resin, though not as high as with food cans, and way less than Polycarbonates. Does anyone know if there are uncoated aluminum beer cans?
It's coated to protect the thin aluminum from the contents. Otherwise it will perforate, evidently within a few days.
I don't know anything about the coatings themselves. I suspect they're heat-resistant, since a lot of food products are canned hot. But are they all? Who knows? We do know they resist acids and alcohol.
Uncoated/unanodized aluminum oxidizes quickly. Removing the coating from a can will probably lead to its quick demise; of course, it doesn't cost anything to experiment!
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Is that for reasons of flavour, shelf life, or safety? I think they only started coating them 20 years ago.
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