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Author Topic: Air Temp Nitinol  (Read 206143 times)

gadgetmall

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Re: Air Temp Nitinol
« Reply #75 on: September 19, 2012, 02:14:44 AM »
Hi  thanks for the response . Good info . When i say HOT i mean hotter than 98.6 . i have not measured it as this Nitinol is only 0.20 mm .. I do have 0.45 in a flat wire also . It is not enough heat to boil anything:) I can see your point though , why not make a big stranded blanket out  of these and possibly stay warm in the winter ..

Tom Booth

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Re: Air Temp Nitinol
« Reply #76 on: September 19, 2012, 04:51:15 PM »
What I mean is; An LTD Stirling Engine will run on the heat from your hand. If the Nitinol stays hot enough to FEEL hot to the touch it should be hot enough to run a Stirling Engine, but what this sounds like to me is a refrigeration cycle.

In a refrigerator a gas is compressed to force it to change phase (condense into a liquid). At that point it gives up a lot of heat which is released to the room through the condenser coils on the back of the refrigerator by convection. Then when the refrigerant is released and allowed to expand it reclaims the heat it lost while under pressure (gets cold) producing the refrigerating effect inside the freezer.

Generally phase change takes place gradually at a constant temperature, like ice melting at 32 F. It can take a long time but eventually all the ice melts (or all the water freezes).

So what I'm thinking is that the bending of the nitinol is more or less equivalent to the compression phase in refrigeration where the refrigerant changes phase from a gas to a liquid under pressure. When the Nitinol is released it tries to reclaim the heat it lost like a refrigerant when it is released from pressure and allowed to change phase back into a gas.

So what I'm imagining is that the Nitinol when bent is going through some kind of gradual phase change similar to water freezing. It will continue to give off heat at a constant temperature for a long time until the phase change is complete, but my guess is that it will cool off eventually. Like a block of ice melting, that could take hours or even days.

The fact that the Nitinol gets cold when released from stress indicates to me that it has given up heat that it then wants to reclaim when released from being bent. I'm guessing that as in any phase change, this takes place gradually over time at a constant temperature. Like a pot of boiling water will stay at 212 F until all the water changes phase no mater that you keep adding more heat or a block of ice will stay at 32 F until it all melts.

In other words, I think the bent or stressed Nitinol may give up heat gradually at a constant temperature, say a little above body temperature, but in a normal phase change this cannot continue indefinitely, though I don't discount the possibility that with Nitinol, perhaps something abnormal is going on and the phase change never completes due to some sort of quantum mechanical brownian motion or cashmere effect or something. If that is the case that would be really remarkable but my guess is that eventually the bent Nitinol will cool down completely.

I wonder if anyone has ever done this (bent nitinol to get it hot) to see what happens using an infrared camera. That might be interesting.

Anyway I need to send away for some of this stuff ASAP I think.

Tom Booth

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Re: Air Temp Nitinol
« Reply #77 on: September 19, 2012, 05:12:31 PM »
BTW, after posting, I see advertisement links appearing in the text of my post that I didn't put there. Is that normal for this site or have I picked up some kind of adware on my computer ? 

Paul-R

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Re: Air Temp Nitinol
« Reply #78 on: September 19, 2012, 05:51:25 PM »
BTW, after posting, I see advertisement links appearing in the text of my post that I didn't put there. Is that normal for this site or have I picked up some kind of adware on my computer ?
I think that is pretty normal. The site drips with advertising which is why every page
is so data bulky.

gadgetmall

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Re: Air Temp Nitinol
« Reply #79 on: September 19, 2012, 06:25:39 PM »
Hi Tom . Very nice explanation but i am not a physicist and all i know is what i see and do . That is a good suggestion . I will try and find that information i was reading where scientist  put the color changing thermal liquid crystal on it . they see what i see but  infrared imagery would be real proof  .

This only works if the Nitinol is in its austinite stage or it's parent state . As long as the wire is in that stage where it is stiff as steel wire and has a strain put on it it crys heat . Now i got several pieces i keep in my pocket for demos on the go . Springs and stuff i made with it and i can bend the stiffest piece i annealed for temp range above 100f  and it does stay warm even in my cool house / I tried this unscientific by bending it on my lip and feeling the heat and waiting ,then place the unstrained wire on my lip it feels cool like the air temperature in here now 73f it really don't conduct heat from my body and stays kind of cool.You would think it would conduct my body heat and transfer it to the metal . it don't do it very well  . I also tried bending it off my lip then wait a min and put it on my lip and it is very warm . just as soon as i start to release  some of the strain pressure it starts to get colder than the room temp then it seems to return to ambient temperature or just a bit under . The cold is really quite cold .and the heat is an amazing plus considering it looks just like wire . i also tried this with guitar string . nada.. :)

I hope i am not loosing my mind here and i know someone else has some Nitinol in my thread so if you do please speak up and verify this this if you can.

Tom i recommend that 40 foot roll to everyone as i have tested all of the ones available including Magic wire and Dental brace wires. I Do like the 0.025X0.045 thermal dental brace wire from China. it is flat and Strong as hell and comes pre conditioned in a U shape and holds it's shape if you bend it in 50 degrees It transforms fast and super strong . and these  can be tuned easy with just some small batteries or ultra caps like i use . I tried the others as well much thinner brace wire (11cents a pack of 10) and has to be annealed first . The key to getting it close as possible to martinsite with no elasticity at room temperature is the key reason this wire is the right mixture of Ni Ti . i understand from reading that just 1 thousandth more or less will make inferior Nitinol for the purpose i  am using it for . 

Gadget
« Last Edit: September 19, 2012, 11:20:29 PM by gadgetmall »

Tom Booth

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Re: Air Temp Nitinol
« Reply #80 on: September 19, 2012, 11:29:39 PM »
gadgetmall, I wouldn't sweat it too much. I believe your perceptions are most likely correct and you are not going crazy or anything, it is just hard to believe.

But there are many strange phenomenon in Physics, under certain conditions.

Like at the "triple point", water can freeze and boil at the same time.

The properties of Nitinol are so unusual I wouldn't really put anything past it. Still, I would like to get some and make some of these kinds of observations for myself. My intention is to do just that ASAP.

I went to one website recently that advertised small Nitinol strips of some sort that sounded interesting. there wasn't any price. I emailed for a price quote which I just got back today:

Length                       : 20mm
Quantity                     : 1 pc          Price : $ 1088.00 / pc

Needless to say I'll be looking elsewhere. I noticed you posted some links earlier to some Nitinol wire for sale on Ebay for about $20 or something. I'll check it out.

gadgetmall

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Re: Air Temp Nitinol
« Reply #81 on: September 20, 2012, 03:33:11 AM »
gadgetmall, I wouldn't sweat it too much. I believe your perceptions are most likely correct and you are not going crazy or anything, it is just hard to believe.

But there are many strange phenomenon in Physics, under certain conditions.

Like at the "triple point", water can freeze and boil at the same time.

The properties of Nitinol are so unusual I wouldn't really put anything past it. Still, I would like to get some and make some of these kinds of observations for myself. My intention is to do just that ASAP.

I went to one website recently that advertised small Nitinol strips of some sort that sounded interesting. there wasn't any price. I emailed for a price quote which I just got back today:

Length                       : 20mm
Quantity                     : 1 pc          Price : $ 1088.00 / pc

Needless to say I'll be looking elsewhere. I noticed you posted some links earlier to some Nitinol wire for sale on Ebay for about $20 or something. I'll check it out.

O yea jdmedical . gave me a quote like that too it was for just a little  strip . and forget www.nitinol.com unless you are really rich .they thinks its gold because they sell to the medical industry that  use it for stents and teeth. I don't think they have caught on that is also comes from china a 500 times cheaper and in the Quality we are getting it off Ebay :)  16 grams for 19.95 shipping included .the guy who is selling it is also a Nitinol motor maker and sent me some of his Special wire because i bought so much . it is 0.23 . it takes a LOT of cold for that one though .. The guy i posted the link IS the best around in the US and the quality is very high . .
I will keep you posted as progress is made .thanks for the input .


BTW . you can KILL your nitinol with too much heat during annealing and after too . i have several pieces that are dead because i fried them to the point they are just pieces of wire and will hardly move at all .
Albert 

Tom Booth

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Re: Air Temp Nitinol
« Reply #82 on: September 22, 2012, 01:35:50 AM »
BTW . you can KILL your nitinol with too much heat during annealing and after too . i have several pieces that are dead because i fried them to the point they are just pieces of wire and will hardly move at all .
Albert


About that. Earlier you wrote:

Quote
Some tell you 600c or 1122 c . That is BS . As far as i can tell you do not need to get the wire that hot . In Fact you will damage this wires Crystalline properties and mess it up permanently If you get it much higher than 600-700 degrees F. Heres why thru experimenting i have found the perfect ANNEAL for my Nitinol wire . I took three pieces 6 inches long. the first piece i used three high amperage Ultra super caps at 2.7 volts each and used needle nose pliers connected to neg and pos and let the first wire glow red for a bout three seconds then disconnected it very fast and let it fall in a bowl of ice water . The transformation temp is high as it takes very hot water to transform . The second piece i used two ultra caps 5.4 volts and did the same thing except i let it barley glow then dunked it in ice water . the transformation now occurs at luke warm water ..Now the third piece i used only one 2.7 volt ultra cap .. I watched the wire change color from golden amber to blue,no glow then dunked it in ice water . Now i have air temp Nitinol and will change to the  austenite stage at room temperature and really fast using body temp and it only needs cool water not ice water to make it flexible and in the martensite state . So DO NOT LET THE WIRE GET RED .you only need enough heat to change the wires color then ice water to anneal it to make air temp nitinol.

This is probably an ignorant question but I'm not really familiar with capacitors, except that we used to have fun shocking each other with them in small engine repair class back in high school.

Is there a difference between "ultra caps" and "ultra super caps" ?

Where can I get these - Radio Shack ? I live in the country and there isn't much else around here in terms of electronics. An old computer maybe ? I ave a few of those around.

Any particular brand of ultra cap ?

Why a capacitor and not just a regular battery ?

Also, do you have to wait until it is hot before bending it or could you, for example, if you wanted to make a spring,... wrap it around a ceramic cylinder and clamp it in position and then put the whole thing in a really hot oven (Self cleaning cycle ?).

Is dropping it in ice water absolutely necessary or could you just let it cool down gradually ?

I never worked with this stuff before so I hop you don't mind all the questions. Also I don't want to spend money on the stuff and then just end up ruining it out of sheer ignorance so any additional details, tips or whatever about this annealing process would be welcome.

One other thing. Now if I can remember what it was I wanted to ask.

Oh yeah, the instructions you gave were for a 6 inch piece of Nitinol. What thickness ? What if the piece I want to anneal is shorter, longer, thicker,  thinner...

Probably just have to experiment I guess. I don't suppose you've worked up a specifications chart for annealing different lengths or anything but I guess it doesn't hurt to ask.

Anything else I would need to know in regard to working with this stuff ?

You mentioned you were on the East Coast and it was 116 degrees at the beginning of the thread. I'm also on the East coast (USA) but further north no doubt as it was hot here (New York) this summer but not THAT hot .

gadgetmall

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Re: Air Temp Nitinol
« Reply #83 on: September 22, 2012, 02:37:36 AM »
Hey Tom :see this demo http://www.youtube.com/watch?v=EoWMF3VkI6U
  The Ultra Caps are like batteries . they have massive amperage in a small package . here are the Specs and Brand:
Maxwell ultracapacitors Bcap1200
Capacitance: 1200.0 F -10/+20%
Voltage: 2.7V
Dimensions: L = 74mm, OD = 60.7mm
Temperature Range: -40°C to +65°C

Features:
2.7V operating voltage
Ultra low internal resistance
Over 1 million duty cycles
Threaded terminal

Applications:
Backup power
Grid Stabilization
Transportation
Automotive subsystems
Rail system power

They have them on ebay much higher farads 2700 farads  2.5volts /  will fry penneys in a flash
http://www.ebay.com/itm/Maxwell-2600-Farad-2-5V-Ultracapacitor-solar-power-storage-EV-used-/300634728406?pt=US_UPS_Batteries_Components&;hash=item45ff39e7d6

i use them instead of batteries because they have so much power and last longer than batteries and i can series them to match the wire length Plus they last for months charged up and it takes me 1 Minuit to charge a string of 7 ultra-caps with my 30 amp smart charger. the Nitinol has a high resistance and the longer the more power you need . . i have over 50
of them . ranging from 650 farads to 2700farads all 2.5- 2.7 volts each . i can control the heat with these . i cannot with a battery or a battery does not have enuff amperage to heat the wire to a proper anneal.these  6 of the 650 farads will start my truck or run my inverter . i have some on solar panels and some on projects . they are worth the money as they never wear out over one million charge discharge cycles more than my life time and they are light .

The Length of that roll is 40 feet long . the thickmess is supposed to be .020 about the size of a second string on an electric guitar or the size of a straight pin. it will stick you with a one inch piece .

the pieces i carry on me i put loops on the ends and covered them in latex so i dont get stuck anymore .

you can cut it with a strong pair of cutters but you cannot fatten it up .

The process of anneling is also the process of training the wire to transform from how to cold so yes the hot is quenched with ice cold water . to make a spring i use a ceramic rod and clamp one end wind it [very  very hard to do) and kkep the tention on it with a pair of needle nose pliers and either hit it with a tiny torch on the table running or hot it with super cap set up made to touch the pliers with clips . once it smokes i have a big bowl of crushed ice and water and dunk it my hands and pliers in it then do it over again at least 3-5 times / if you do that you train it to learn warm from cool and change in tap water and inside air .
« Last Edit: September 22, 2012, 07:07:47 AM by gadgetmall »

Paul-R

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Re: Air Temp Nitinol
« Reply #84 on: September 22, 2012, 04:36:07 PM »
The Ultra Caps are like batteries .
As they are discharged, does the voltage start dropping immediately, or like
a battery, do you get most of the power at the rated voltage, which drops
as the cap empties?

gadgetmall

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Re: Air Temp Nitinol
« Reply #85 on: September 22, 2012, 05:20:56 PM »
As they are discharged, does the voltage start dropping immediately, or like
a battery, do you get most of the power at the rated voltage, which drops
as the cap empties?
hello Paul-R . the Volts will drop but the current is still there . One of those Big 2700 farads last months of experimenting . you can see in that demo of that particular Ucap that even after shorting and burning it has more power left . Enough to start fires and melt wires even at .5 volts they make wires glow .I think i remember it was calculated that a 650 farad ultracap charged can release 3500 amps all at once but they won't go dead that fast . In a dead short it take a while before all that energy goes away . The amazing thing about them is i can charge one up in less than 20 seconds to full capacity and it will run several circuits for months and months ..That deal on ebay is a steal for less than 25 dollars  . These things 4 years ago were 400 dollars each . and the 650 was close to 190.00 I used to sell them and get them from the manufacture in cases  and sell them at a discount .but soon found out i can get them off ebay for a fraction of the cost . No one can compete with Ebay's prices .Very good value and Quality . However i have bought leaky ones from a seller . They have an electrolyte in them ,just a few drops and i have seen some not welded properly and that poison stuff is gone and the bcap is like a normal capacitor  when i tried and charge them. just a few .
« Last Edit: September 22, 2012, 08:04:16 PM by gadgetmall »

Lakes

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Re: Air Temp Nitinol
« Reply #86 on: September 22, 2012, 06:50:15 PM »
Good for a bit of spot welding then... :)

gadgetmall

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Re: Air Temp Nitinol
« Reply #87 on: September 22, 2012, 07:13:48 PM »
Good for a bit of spot welding then... :)
true . carbon rods really light up and get HOT.

DreamThinkBuild

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Re: Air Temp Nitinol
« Reply #88 on: September 22, 2012, 07:20:32 PM »
Hi Paul-R,

Caps are linear devices, they discharge/charge linearly based on current draw/amps. They lack the Ah of a battery but make up for it in sheer power output(high current)/quick charging time.

Hi Gadget,

Solar+Ultracaps make the perfect couple. I have a solar spot light I got from Lowes and replaced the weak batteries that would be dim by morning with two 3000F ultracaps. It runs all night brightly for a hall light.

Have you tried ambient charging with ultracaps? Short one out through a 10ohm power resistor to about 10mv, take off the load and leave it. Check the voltage in about 2 hours the voltage should start to climb, I usually get about 200mv+ by the end of the day.

Hi Lakes,

Arc welding is easy with them. :)

gadgetmall

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Re: Air Temp Nitinol
« Reply #89 on: September 22, 2012, 07:39:43 PM »
Inside the Bcap :

An ultracapacitor stores energy electrostatically by polarizing an electrolytic solution. Though it is an electrochemical device there are no chemical reactions involved in its energy storage mechanism. This mechanism is highly reversible, allowing the ultracapacitor to be charged and discharged hundreds of thousands to even millions of times.
An ultracapacitor can be viewed as two non-reactive porous plates suspended within an electrolyte with an applied voltage across the plates. The applied potential on the positive plate attracts the negative ions in the electrolyte, while the potential on the negative plate attracts the positive ions. This effectively creates two layers of capacitive storage, one where the charges are separated at the positive plate, and another at the negative plate.
Conventional electrolytic capacitors storage area is derived from thin plates of flat, conductive material. High capacitance is achieved by winding great lengths of material. Further increases are possible through texturing on its surface, increasing its surface area. A conventional capacitor separates its charged plates with a dielectric material: plastic, paper or ceramic films. The thinner the dielectric the more area can be created within a specified volume. The limitations of the thickness of the dielectric define the surface area achievable.
An ultracapacitor derives its area from a porous carbon-based electrode material. The porous structure of this material allows its surface area to approach 2000 square meters per gram, much greater than can be accomplished using flat or textured films and plates. An ultracapacitors charge separation distance is determined by the size of the ions in the electrolyte, which are attracted to the charged electrode. This charge separation (less than 10 angstroms) is much smaller than can be accomplished using conventional dielectric materials.
The combination of enormous surface area and extremely small charge separation gives the ultracapacitor its outstanding capacitance relative to conventional capacitors.