The option of entering an ID and a number of wraps is already on my to do-list, which by the way is unsorted, so I have no idea when. But it will be added eventually.
Great, thanks!
TC beyond Ni200: Nickel Purity, Dicodes; Ti, SS, Resistherm NiFe30; Coefficient of Resistance
- Thread starter TheBloke
- Start date
- th_trl_thread_readers 0
- Status
Great, thanks!
So, I found a piece of data that I'd like to run by some of the technical minded here.
Whenever someone asks about coil material and safety, someone else will bring up the dangers chemicals that can be formed from nickel, titanium, or steel. Then someone else well bring up that you aren't going any where near the melt, much less the vaporization temps, and then the whole thing is dropped, and everyone moves on.
I understand we aren't going near the melt point of the materials, but that doesn't mean they aren't pitting off vapor. On a nice 77 degree F day (25 celsius), you're about 3 times closer to the freezing temperature of water than you are to the vaporization temperature of water... but water will still evaporate away.
Now, I understand the structure of steel, and know the molecular "cages" of iron don't open up enough to let out impurities at temperatures we are working at. However, I do not know the same thing about nickel, or titanium, so I looked for it.
What I found was a chart (actually 2 charts) of vaporization pressures of different metallic elements at various temperatures, with melt temps. (URL at the bottom)
I'm not sure if this is accurate, and it does not appear to go down to a zero.
Does anyone know if this is accurate, our if this it's a legitimate concern for these materials?
The site is:
Vapor pressure of the Chemical Elements, vapor pressure of metals
and halogens from -150 degrees C to 3500 degrees C including lead, aluminum,
zinc, iodine, copper, indium, iodine, magnesium, selenium, lithium, iron,
sodium and gallium
Whenever someone asks about coil material and safety, someone else will bring up the dangers chemicals that can be formed from nickel, titanium, or steel. Then someone else well bring up that you aren't going any where near the melt, much less the vaporization temps, and then the whole thing is dropped, and everyone moves on.
I understand we aren't going near the melt point of the materials, but that doesn't mean they aren't pitting off vapor. On a nice 77 degree F day (25 celsius), you're about 3 times closer to the freezing temperature of water than you are to the vaporization temperature of water... but water will still evaporate away.
Now, I understand the structure of steel, and know the molecular "cages" of iron don't open up enough to let out impurities at temperatures we are working at. However, I do not know the same thing about nickel, or titanium, so I looked for it.
What I found was a chart (actually 2 charts) of vaporization pressures of different metallic elements at various temperatures, with melt temps. (URL at the bottom)
I'm not sure if this is accurate, and it does not appear to go down to a zero.
Does anyone know if this is accurate, our if this it's a legitimate concern for these materials?
The site is:
Vapor pressure of the Chemical Elements, vapor pressure of metals
and halogens from -150 degrees C to 3500 degrees C including lead, aluminum,
zinc, iodine, copper, indium, iodine, magnesium, selenium, lithium, iron,
sodium and gallium
Ahh... let me try to shed some light here. My understanding of vapor pressure, and keep in mind this is college intro to chemistry level, not phd level understanding, is...
Vapor pressure is the pressure of the off gassing of a material at a given temperature. NOT the temperature/pressure that the material vaporizes. For example, for water, again at 25 celsius, the vapor pressure is 23.77 torr (or mm of mercury if you prefer, they're the same unit.) This means that at this temperature the water will continue evaporating into the air, until it is saturated with about 23.77 torr of water distributed through out the air mass. It doesn't matter that there's 760ish torr of air, if at least 23.77 torr of that total pressure is not water, the water will evaporate anyway.
In other words, those low numbers I do not think are saying the air pressure has to be that low to get vaporization, it is saying those lines represent the atmospheric partial pressure of the off gassing from those materials, even at standard room pressures. Also, again, see that the bottom of the chat is not 0, although it is a small amount.
Vapor pressure is the pressure of the off gassing of a material at a given temperature. NOT the temperature/pressure that the material vaporizes. For example, for water, again at 25 celsius, the vapor pressure is 23.77 torr (or mm of mercury if you prefer, they're the same unit.) This means that at this temperature the water will continue evaporating into the air, until it is saturated with about 23.77 torr of water distributed through out the air mass. It doesn't matter that there's 760ish torr of air, if at least 23.77 torr of that total pressure is not water, the water will evaporate anyway.
In other words, those low numbers I do not think are saying the air pressure has to be that low to get vaporization, it is saying those lines represent the atmospheric partial pressure of the off gassing from those materials, even at standard room pressures. Also, again, see that the bottom of the chat is not 0, although it is a small amount.
Everything has a vapor pressure and a certain number of atoms are evaporating all the time, from everyting, all around us. If the vapor pressure is really low for a given material there might only be one atom per cubic mile of space (or less) ...but there's a lot of stuff around us so it's likely that every breath we take has maybe a calcium atom or a iron atom or whatever. There is no such thing as absolutely pure air. I've said before that everything is evaporating and condensing at the same time and if we wait long enough Mt Everest will entirely evaporate but that's going to be multiple billions of years from now....and the sun will have expanded and swallowed the earth before it occurs.
My bottom line is if we're worried about the evaporation of Iron, Nickel or Titanium during vaping then we're way too worried about things and our only hope to avoid such things like that is to absolutely quit breathing even clean air.
That's not an option I'm eager to try for a long time.
Duane
My bottom line is if we're worried about the evaporation of Iron, Nickel or Titanium during vaping then we're way too worried about things and our only hope to avoid such things like that is to absolutely quit breathing even clean air.
That's not an option I'm eager to try for a long time.
Duane
Thomas from Zivipf got the NiFe30 wire. I don`t know which one, but I will get a sample soon. I will let you know.
Edit: Ring ring, the wire arrived. I got 0.28mm and 0.25mm. The 0.28mm NiFe30 is 3.25 Ohm/m - measured. I will test it this night.
Zivipf perpared the shop already for NiFe30 NiFe30 - Zivipf Onlineshop
I guess Thomas will list the wire as soon as he got some feedbacks.
Last edited:
Awesome!
Please measure the resistance of the 0.25mm. 0.25 is the same that Dicodes supplies as Resistherm, so it will be interesting to see how the reisstance compares. The Dicodes Resistherm 0.25mm is 5.5Ω/m
If you don't mind me nerding around (again) I just would like to make some entirely irrelevant comments:
".. vaporization is the production of a vapor or gas from matter in another physical state... When vaporisation occurs from liquids, it is known as evaporation; when it occurs from solids, it is called sublimation....."
And this process is, as @druckle pointed out, happening continuously. As per today, and AFAIK, it is because some atom/molecule due to its relative higher kinetic energy escapes/get kicked out of the liquid/solid. And another is coming back. And yes, the rate is temperature and ambient pressure dependent. But I don't really worry about it.
However, I really would see some thorough study on the things that might get dissolved in our liquid and inhaled with it.
".. vaporization is the production of a vapor or gas from matter in another physical state... When vaporisation occurs from liquids, it is known as evaporation; when it occurs from solids, it is called sublimation....."
And this process is, as @druckle pointed out, happening continuously. As per today, and AFAIK, it is because some atom/molecule due to its relative higher kinetic energy escapes/get kicked out of the liquid/solid. And another is coming back. And yes, the rate is temperature and ambient pressure dependent. But I don't really worry about it.
However, I really would see some thorough study on the things that might get dissolved in our liquid and inhaled with it.
Last edited:
Ok, good answer @druckle that is reassuring to me that others have seen and considered this information.
Also, all, I am sorry if it seemed I was thread jacking, didn't think of that until after I posted, but in my defence, 1) this is probably the most intellectual discussion of tc, so a good place to get answers, and 2) the safety of different materials I think is on topic for a discussion of tc on different materials.
@vapealone glad to hear I'm not the only person interested. I'm going to run this same info by a person with a phd in organic/inorganic chem to see if they can point me to some good info as well. Will post at least a link to more info if I find it.
Also, all, I am sorry if it seemed I was thread jacking, didn't think of that until after I posted, but in my defence, 1) this is probably the most intellectual discussion of tc, so a good place to get answers, and 2) the safety of different materials I think is on topic for a discussion of tc on different materials.
@vapealone glad to hear I'm not the only person interested. I'm going to run this same info by a person with a phd in organic/inorganic chem to see if they can point me to some good info as well. Will post at least a link to more info if I find it.
Sorry Tom, but Dicodes offers only a custom made Resitherm wire in 0.28mm/ 5.5Ohm/m - Resitherm offers regular NiFe30 up 0.25mm. ( Yes, sometimes there is too much input and too many numbers
)So the Zivipf NiFe30 is not from Resitherm
0.25mm = 4.038 Ohm/m
0.28mm = 3.314 Ohm/m
measured with Keithley
I will do my standard dry cotton test on the SXK VS (420F) and see where the NP is.
This has been a fantastic & thought provoking thread. I'm new to ecf and grateful to have such a platform to facilitate discussions such as this. I thought I'd get of the sidelines and try to contribute. Although Vaporization is a detour from topic there is a practical side that I've never seen discussed & does tie in to the topic of temp control coil build strategery. So here goes. There seams to be a wide spread consensus that Ni200 & Titanium coils should not be dry fired or to put another way they should not be oxidized prior to use (the reasons why I'll leave to other threads). As a consequence of this, both Ni200 & Titanium tend to have unstable TCR results when built as contact coils, thus It is becoming the norm to build spaced temp coils. Bear with me; I promise I'll get to the point eventually. It is a normal practice to oxidize most common coil materials prior to use. I think it's more just done out of habit, std practice, or the practicality of being able to shape the coil & make sure it's heating from the center out without hot spots. I don't think most vapors realize that when they heat the coil to a bright glow 1500°F + they are actually forming/growing an oxide layer on the coil surface. I see videos of people jiggling hot coils & strumming them like a guitar and wallah; magically the hot spots disappear. I've yet to hear someone explain why. It is this beneficial oxide layer that straightens out the hot spots. The surface oxide layer that forms is an electrical insulator it is what makes successful contact coils possible. when a coil is dry fired and a hot spot (short/arc) is observed, its likely the result of the coils being in full contact prior to being oxidized so then when you jiggle the coil or strum it you open up a tiny gap just big enough for the oxide layer to form on the next pulse & your hot spot goes away. The Below excerpt (less then 300 words) was taken from Here http://www.kanthal.com/Global/Downloads/Materials%20in%20wire%20and%20strip%20form/Resistance%20heating%20wire%20and%20strip/S-KA026-B-ENG-2012-01.pdf
"The protective oxide layer on Kanthal® alloys formed at temperatures above 1000°C (1830°F)
consists mainly of alumina (Al2O3). The color is light grey, while at lower temperatures (under
1000°C (1830°F)) the oxide color becomes darker. The alumina layer has excellent electrical insulating properties and good chemical resistance to most compounds.
The oxide formed on Nikrothal® alloys consists mainly of chromium oxide (Cr2O3). The color is
dark and the electrical insulating properties inferior to those of alumina.
The oxide layer on Nikrothal alloys spalls and evaporates more easily than the tighter oxide layer
that is formed on Kanthal alloys.
Nikrothal is just kanthal's brand of Nichrome 80 & 60, Ni200 forms a "suspicious" Nickel oxide layer, & Titanium forms a "suspicious" titanium oxide layer. So when we hear of uninsulated contact coils built from un-oxidized Ni200 or Titanium with unstable resistance readings it means (there are shorts across the coils) basically the coils are being arc welded together at extreme localized temps hot enough to weld and or vaporize the metal. That to me is the scary side of Vaporization from a practical standpoint. OK let me try to somehow get back on thread topic. I'm not a big fan of building hybrid temp control coils for this very reason. It seems you've got to pick the lesser of 2 evils with them. Either you oxidize the hybrid and choose to accept the "suspicious" oxide, or you don't dry fire & accept the fact that some amount of metal/e liquid is going to be vaporized at extreme temps since shorts withing the unoxidized coils are inevitable. The more elaborate the hybrid the more opportunity for shorts. Personally I don't use Nickel coils. I like to build contact coils & I want my coils oxidized. To me the NiFe coils are the most promising. I have less apprehension about a Nickel/Iron oxide layer then I do for the other options.
"The protective oxide layer on Kanthal® alloys formed at temperatures above 1000°C (1830°F)
consists mainly of alumina (Al2O3). The color is light grey, while at lower temperatures (under
1000°C (1830°F)) the oxide color becomes darker. The alumina layer has excellent electrical insulating properties and good chemical resistance to most compounds.
The oxide formed on Nikrothal® alloys consists mainly of chromium oxide (Cr2O3). The color is
dark and the electrical insulating properties inferior to those of alumina.
The oxide layer on Nikrothal alloys spalls and evaporates more easily than the tighter oxide layer
that is formed on Kanthal alloys.
Nikrothal is just kanthal's brand of Nichrome 80 & 60, Ni200 forms a "suspicious" Nickel oxide layer, & Titanium forms a "suspicious" titanium oxide layer. So when we hear of uninsulated contact coils built from un-oxidized Ni200 or Titanium with unstable resistance readings it means (there are shorts across the coils) basically the coils are being arc welded together at extreme localized temps hot enough to weld and or vaporize the metal. That to me is the scary side of Vaporization from a practical standpoint. OK let me try to somehow get back on thread topic. I'm not a big fan of building hybrid temp control coils for this very reason. It seems you've got to pick the lesser of 2 evils with them. Either you oxidize the hybrid and choose to accept the "suspicious" oxide, or you don't dry fire & accept the fact that some amount of metal/e liquid is going to be vaporized at extreme temps since shorts withing the unoxidized coils are inevitable. The more elaborate the hybrid the more opportunity for shorts. Personally I don't use Nickel coils. I like to build contact coils & I want my coils oxidized. To me the NiFe coils are the most promising. I have less apprehension about a Nickel/Iron oxide layer then I do for the other options.
I'm vaping on a titanium fused clapton for a week now. I didn't dry burn it, I did the dry cotton test first, no hot spots, prefect tc. Very good vape with no problems at all. I did mesh my previous titanium clapton when I pulced it in tc while pressing it with my tweezers. It almost melt. It did work fine for a week since then. So build it and use it as it is and it works fine.
Ok, I made my dry cotton tests. 0.28mm wire, SXK reads 0.28Ohm ( DNA40 and Keithley say 0.32 Ohm ). SXK set to 420F and 40W, I started with NP 30 and came to NP 56 when the cotton was light brown. So I would say the TCR is quite high and around 50. This is not Resitherm NiFe30 for sure - too low Ohms/m and too high TCR.
Thanks @WileE I had a look in the Kanthal Datasheet. On page 72+73 they show the specs for Nifethal 70. They don`t write the TCR but they write the resitifity increase from 20C to 100C and from 100 to 200C
- 20C = 1
- 100C = 1,42
- 200C = 1,91
This means: The TCR between 20C and 100C is 0.0052 and from 20C to 200C 0,0050555. Sounds not bad in case of my unknown wire. And on page 73 they write the Ohms/m for my diameters
0.28mm = 3.25 Ohm/m and 0.25mm = 4.07 Ohm/m
I guess, no, I´m sure the Zivipf wire is Kanthal Nifethal 70
Thanks @WileE I had a look in the Kanthal Datasheet. On page 72+73 they show the specs for Nifethal 70. They don`t write the TCR but they write the resitifity increase from 20C to 100C and from 100 to 200C
- 20C = 1
- 100C = 1,42
- 200C = 1,91
This means: The TCR between 20C and 100C is 0.0052 and from 20C to 200C 0,0050555. Sounds not bad in case of my unknown wire. And on page 73 they write the Ohms/m for my diameters
0.28mm = 3.25 Ohm/m and 0.25mm = 4.07 Ohm/m
I guess, no, I´m sure the Zivipf wire is Kanthal Nifethal 70
Last edited:
For some reason that I don't really understand, a uniform length of something tend to heat up from the middle. Assuming that your coil is uniform, it means that from a simply loop to a micro-coil everything will heat up from the middle, given that you have no internal arch.
The advantage of the contact or micro coils over spaced coils is that the temperature of the coil will be more uniform as they are heating up each other by the otherwise lost heat. Compare to that, a macro coil can glow nicely in the middle and be completely dark and way cooler a wrap or two away.
In other word:
The closer the wraps are the more uniform the coil temp will be. Oxide layer simply helps you to bring the spacing to the very minimum without shorting/arching. And also help to adjust for imperfect build which is good as our builds are imperfect.
The further the wraps are the less uniform the coil temp will be but the more likely that the coil will not short/arch thus the more likely that you will not need any adjustment.
Me too
Not because the oxide issue but because I like micro-coils.
Too bad, that I have the Kanthal Nifethal70 equivalent not the Resistherm type. The later has higher resistance, although lower TCR ( probably because of its Cr content?) thus seems more versatile to me. Besides, my wet dream is some Nifethal52/NiFe52 with higher resistance and TCr than Resistherm
PS: ATM I vape on TI micro-coils. I wrapped them as normal contact coils and the springiness of Ti and my struggle to place it in the atty just opened the space enough for a good non-contact micro-coil
No short, no oxide but happiness
Last edited:
Actually, much has been written on the oxidation of kanthal here on ecf. It's been covered forwards and backwards and everything in between. For a "forward" version check my blogs.
As far as tc I use Ti and I do anneal it before wrapping coils. It conforms to my winding mandrel better that way. I do wash it before winding to remove any oxides that could have developed. Still, I don't use contact coils anymore, they are too short lived for my liking. I'm a spaced coil kinda guy and after winding hundreds of both types of coils it would be difficult to justify going back to the more efficient firing but short lived contact coil; battery tech has come a long way.
As far as kanthal coils welding together causing shorts, I don't know. Seems like we are not getting the kanthal hot enough while dry firing to reach plasticizing temps, however we could be getting it hot enough to cause ionic arching; a short in every sense. In any case I suspect that the shorting is proximity related; the turns are touching until alumina forms. I think raking, strumming and other techniques are just introducing enough oxygen into the shorted area to allow proper ionic diffusion of the base metals for proper alumina formation. Guessing here.
As far as dryfiring Ti? Yes I do.
The Ti coil above has had 21 dry firings and 7 wick changes. I dry fire at 25w to a medium red color then wash and repeat 3 times before rewicking. So far so good.
OMG, I would have never found that there
Luckily, it is listed on their webpage as wellBTW, you can find approximated TCRs and TFRs for the whole vaping range in this thread if interested but bear in mind that the used curve doesn't give 100% accuracy, although precise enough. My only excuse is that the listed values aren't rock solid either but a sort of median values. At least that is what I keep saying to myself
P.S.: And the Nifethal70 is probably the least accurate. It was one of the first I have done and didn't bother to refine. But if Zivipf is indeed selling this I might need to
Last edited:
GOtta say, I love the work you guys are doing. If I had the time/means, I would help.
So, do we have any idea on the TCR/TFR on the Alloy 120 that is available in the US? resistancewire.com lists theirs as "Alloy 120" with a million other names, to include Nifethal 70 - Want to see what the current verdict is on that stuff, if there is one. They list the TCR of their product as 4.5e-05, and was wondering if you believed it was accurate. Seeing as it's close to Titanium, I was planning to run it with similar to Titanium settings on a DNA40. Thanks!
So, do we have any idea on the TCR/TFR on the Alloy 120 that is available in the US? resistancewire.com lists theirs as "Alloy 120" with a million other names, to include Nifethal 70 - Want to see what the current verdict is on that stuff, if there is one. They list the TCR of their product as 4.5e-05, and was wondering if you believed it was accurate. Seeing as it's close to Titanium, I was planning to run it with similar to Titanium settings on a DNA40. Thanks!
Ain't tested but keep using
It is softer than Kanthal/Ti etc but not as soft as Ni200. Works as supposed. I do oxidise and dry burn. The only trick I use for micro coils that I heat it up slowly and gradually until it fully oxidised.
And the resistance coefficient they have listed is nominal and refers to 0-100°F (32-212°F) so got a limited use for us.
Besides, on their product page, the 4.5e-05 is very likely a typo (good catch BTW we might need to tell them) as the their datasheet lists it as 0.0045 (4.5E-03) which is more realistic and very close their Ni200's 0.0047.
And to make it worse, the listed TFRs on the datasheet are implicating some lower than TI's resistance changes dubiously close to their A52 (listed TCR 0.0029)
Bottom line: Until Tom tests the very material do a dry cotton test first
BTW: ATM it is 200°C(392°F) for me on a DNA40
Besides, on their product page, the 4.5e-05 is very likely a typo (good catch BTW we might need to tell them) as the their datasheet lists it as 0.0045 (4.5E-03) which is more realistic and very close their Ni200's 0.0047.
And to make it worse, the listed TFRs on the datasheet are implicating some lower than TI's resistance changes dubiously close to their A52 (listed TCR 0.0029)
Bottom line: Until Tom tests the very material do a dry cotton test first
BTW: ATM it is 200°C(392°F) for me on a DNA40
FYI - The (listed TCR .0029) on Hyndman's Data sheet for A52 is wrong (likely a typo) It doesn't match Their temperature factor chart shown below!! A52 TCR is more like .004/°C or .00224/°F in the range 68°- 572°F
- Status
Similar threads
- Locked
- Locked
- Locked
