Thanks guys! I will wait more information before I try it.
Till it is clear whether it's safe or not I can use my stainless steel coil.
Till it is clear whether it's safe or not I can use my stainless steel coil.
TC beyond Ni200: Nickel Purity, Dicodes; Ti, SS, Resistherm NiFe30; Coefficient of Resistance
- Thread starter TheBloke
- Start date
- th_trl_thread_readers 0
- Status
Not so sure how safe ss is to be honest. The tc is so low and dependent on what ss mix you are using I would have thought the chance of drastic tc miscalculation was very high...Thanks guys! I will wait more information before I try it.
Till it is clear whether it's safe or not I can use my stainless steel coil.
Currently I am using SS316L because this one is available at my local vendor.
I have made a water test and the SXK chip measured 98-102°C at 11NP and there isn't significant oxidation on the wire. So it seems to work but of course I am not sure how safe it is but I want to believe it's safer than pure Nickel..
I have made a water test and the SXK chip measured 98-102°C at 11NP and there isn't significant oxidation on the wire. So it seems to work but of course I am not sure how safe it is but I want to believe it's safer than pure Nickel..
I've recieved SS 316L for a week now, today I decided to give it a try. I haven't recieved my infinite VF yet so I tried it to my istick. I was surprised by the rich flavour I get from it. I think it's the best vape I had. I've been only using it since the afternoon but it seems that it stays cleaner than every other coil I've tried. Ti included. 28g, 8 wraps really close but not touching, piece of cake to build the coil without torching or pulsing. I think I'll stick to it till I have the chance to try Ni200 and Ti on TC. Really soon I hope...
Bloke, yes you're right they say it is best to have a spring, but what I think is that is true in the ideal world where spring loaded connectors have stiff springs that remain stiff.
I might probably be biased by the poor experience I've had with several mods (one for all is the VS rdna), but in my experience the average spring loaded 510 doesn't always guarantee a solid connection at least across the spectrum of all the different mods with their different 510 protruding height: considering the pressure the spring exercise varies with the compression, the less protruding 510 you have, a less reliable connection you end with (I ended up not being able to use my squape on the vs rdna, because its resistance jumps all over the place, I'm waiting for a new fatdaddy 510 to be available on stealthvapes UK, as suggested by @tchavei, to try and replace it...)
IOW, my consideration is: given in my experience I haven't found a very consistent spring loaded 510 (except maybe in the very first flask with dna40, which is still one of the best TC mods I have, no glitches lucky me!), I prefer a "real" solid connection from a fixed pin than an ideal-but-difficult-to-find-in-reality spring-loaded connection, even if it would be better on paper.
Hope this makes sense, sorry but English is not my first language...
Ah cool, I am using SS317L with good results as well. I went for 10 NP - I guess it could be either really if we use Dicodes' figure of 105, which is 10.5 on our NP scale. The only coefficient I can find for SS is SS304 which is 0.00094, but I assume from Dicodes' figure that SS316/317 is a little higher, ie 0.00105.
I wonder if there's any significant TCR difference between 316 and 317, that would be interesting to discover. Also differences in how they vape, if there is anything noticeable.
@balazsk have you read Dicodes' Application Guide for TC, it is very very interesting - I think one of the first, if not the first, proper "guides" to TC put out by a mod manufacturer, going into technical detail on how this works. We have all learnt a lot from our own research, and some info that has filtered through from Evolv - very limited though, and often misleading (eg about why Ni200 contact coils don't work). I was very impressed with Dicodes' document. I recommend all to read it (and thanks again to @ndb70 for bringing it up again here)
Anyway I mention it in this context because it uses SS several times as an example. Talking about how with a SS coil at 0.10, every 0.001 inaccuracy is equivalent to a 10°C / 50°F difference, and a 0.01 difference is 100°C / 212°F, compared to Ni200's of 16°C / 60°F with a 0.01 difference.
Overall they say that SS has a temp accuracy of 30°C / 122°F. This sounds bad, but they go on to say that the repeatability is good - ie once you find the right setting for a given atty+SS coil, you can repeat it readily, and more easily than with Ni200. In full:
For example, using Nickel wire, the temperature can be measured to about 5°C accuracy, whereas the stainless steel wire, the initial absolute accuracy is just 30°C. This seems to be quite poor but the relative repeated accuracy is much better. I.e. once an optimal temperature for the best taste of a specific liquid is found (by iterative playing around with the setting) the adjusted temperature can be kept all the time. Important is to follow the recommendations below.
Anyway I recommend everyone read it, very interesting and relevant to TC vaping on all devices.
@balazsk can you give more details on your SS experiences? Coil types, temperature settings (are you using an offset?) etc? I did some earlier experimentation, a few days ago, and had good results. But then I mvoed to Ti and haven't yet gone back. I was just thinking of making a coil this evening actually. The coils I did do I found I did need a temperature offset of about 50°F on average. Which does tie in with the expected accuracy being no more than to the nearest 122°F.
I wonder if there's any significant TCR difference between 316 and 317, that would be interesting to discover. Also differences in how they vape, if there is anything noticeable.
@balazsk have you read Dicodes' Application Guide for TC, it is very very interesting - I think one of the first, if not the first, proper "guides" to TC put out by a mod manufacturer, going into technical detail on how this works. We have all learnt a lot from our own research, and some info that has filtered through from Evolv - very limited though, and often misleading (eg about why Ni200 contact coils don't work). I was very impressed with Dicodes' document. I recommend all to read it (and thanks again to @ndb70 for bringing it up again here)
Anyway I mention it in this context because it uses SS several times as an example. Talking about how with a SS coil at 0.10, every 0.001 inaccuracy is equivalent to a 10°C / 50°F difference, and a 0.01 difference is 100°C / 212°F, compared to Ni200's of 16°C / 60°F with a 0.01 difference.
Overall they say that SS has a temp accuracy of 30°C / 122°F. This sounds bad, but they go on to say that the repeatability is good - ie once you find the right setting for a given atty+SS coil, you can repeat it readily, and more easily than with Ni200. In full:
For example, using Nickel wire, the temperature can be measured to about 5°C accuracy, whereas the stainless steel wire, the initial absolute accuracy is just 30°C. This seems to be quite poor but the relative repeated accuracy is much better. I.e. once an optimal temperature for the best taste of a specific liquid is found (by iterative playing around with the setting) the adjusted temperature can be kept all the time. Important is to follow the recommendations below.
Anyway I recommend everyone read it, very interesting and relevant to TC vaping on all devices.
@balazsk can you give more details on your SS experiences? Coil types, temperature settings (are you using an offset?) etc? I did some earlier experimentation, a few days ago, and had good results. But then I mvoed to Ti and haven't yet gone back. I was just thinking of making a coil this evening actually. The coils I did do I found I did need a temperature offset of about 50°F on average. Which does tie in with the expected accuracy being no more than to the nearest 122°F.
I asked this question in the "End of microcoils" thread, especially asking Magaro who is a PHD of Metallurgy. He didn't have detailed info of course, but his gut reaction was that at TC temperatures it should be fairly safe. I can dig up his exact response if it's of interest.
@ndb70
I don`t know what´s your prefered air draw, but if you like it airy, you could use the air regulating screw [HASHTAG]# B13[/HASHTAG] to get the best conductivity on the K4. I haven`t meassured it on my Keithley 580 Microohmmeter, but I get constant values.
Btw: When you use Titan or NiFe30 builds around 0,5 Ohm, these few 1/1000s Ohm of static resistance will give you a wrong temperature of max 1 degree - I wouldn`t care
I don`t know what´s your prefered air draw, but if you like it airy, you could use the air regulating screw [HASHTAG]# B13[/HASHTAG] to get the best conductivity on the K4. I haven`t meassured it on my Keithley 580 Microohmmeter, but I get constant values.
Btw: When you use Titan or NiFe30 builds around 0,5 Ohm, these few 1/1000s Ohm of static resistance will give you a wrong temperature of max 1 degree - I wouldn`t care
I think SS wire is one of the most flavourful one what I have tried. In the past I used it for microcoils on mech mods like many vapors in Hungary. But to do that you have to oxidize it what is not so easy like Kanthal. Probably it's not the safe way.
For TC I use 0.28mm for non contact coils on 2.5mm diameter. This a thinner wire what heats up quickly and doesn't need too much power.
I vape it on 210°C without any offset because it passed the water test with surprisingly good result (98-102°C). And it works really stable, much more stable than with Ni. The temperature protection works as I can see it in the mirror because I have a VS clone.
I will order some 317L to compare them.
Unfortunately that is not the case, I am pretty sure.
I think you are making the same mistake I made, at first - forgetting that the TCR calculation is relative to the base resistance of the coil. This is why base resistance is so very important.
I just ran some numbers on this TCR Calculator.
Test for temperature detection inaccuracy when resistance is read incorrectly too high by 0.04Ω on a Ti coil of 0.40Ω
Edit: Post corrected to add in static resistance missed out on final calculations, thanks @funkyrudi
In the following lists values I typed are in normal text, values calculated are in bold.
Calculation 1:
Checking the resistance rise for a Titanium coil of 0.40Ω, increasing from 20°C to 232°C (450°F)
Calculation 2:- Resistivity: 0.0035 (Ti)
- Starting temp: 20°C
- Ending temp: 232°C
- Starting resistance: 0.40Ω
- Ending resistance: 0.6968Ω
Checking the resistance rise for a Titanium coil of 0.44Ω, increasing from 20°C to 232°C (450°F)
Calculation 3:- Resistivity: 0.0035 (Ti)
- Starting temp: 20°C
- Ending temp: 232°C
- Starting resistance: 0.40Ω
- Ending resistance: 0.76648Ω
Checking the temperature rise on a coil that is actually 0.40Ω but which is measured as 0.44Ω.
The mod thinks its starting resistance is 0.44Ω, so it calculates a rise to 0.7368Ω as being a temperature of 212.7°C / 414°F when the coil is actually at 232°C / 450°F.
This is an inaccuracy of 19.3°C from a 0.04Ω static resistance.
- Resistivity: 0.0035 (Ti)
- Starting temp: 20°C
- Ending temp: 212.7 °C
- Starting resistance: 0.44Ω
- Ending resistance: 0.7368 (= 0.6968Ω + 0.04Ω static resistance)
The mod thinks its starting resistance is 0.44Ω, so it calculates a rise to 0.7368Ω as being a temperature of 212.7°C / 414°F when the coil is actually at 232°C / 450°F.
This is an inaccuracy of 19.3°C from a 0.04Ω static resistance.
This highlights how important the starting resistance calculation is. The ending resistance calc is much less important. But starting resistance is vital because this is the number used for the TCR calculation. Therefore starting resistance errors are heavily compounded - the higher the TCR, the more they compound. So it is worse with Ni200 than Ti/NiFe30, but still bad enough with these wires too.
That is a hopefully somewhat extreme example, a difference of 0.04Ω. (Though KF4 has been measured by @ndb70 at 0.03Ω)
Doing the same calculation for a difference of 0.01Ω:
Calc 1 - same as above for 0.40Ω coil to 232°C
Calc 2 - checking resistance of 0.41Ω, ending resistance is 0.71422Ω
Calc 3 - checking temperature predicted from coil detected as 0.41Ω rising to 0.7068Ω (0.6968Ω for actual 0.40Ω coil + 0.01Ω static resistance) = 226°C instead of 232°C.
So a 0.01Ω static resistance is affects the reading by 6°C with Titanium.
Calc 2 - checking resistance of 0.41Ω, ending resistance is 0.71422Ω
Calc 3 - checking temperature predicted from coil detected as 0.41Ω rising to 0.7068Ω (0.6968Ω for actual 0.40Ω coil + 0.01Ω static resistance) = 226°C instead of 232°C.
So a 0.01Ω static resistance is affects the reading by 6°C with Titanium.
Last edited:
I think (hope) that a whole lot more attention to the contact resistance and inherent resistance of atomizer devices might be coming sometime in the future. I've had a real hard time getting consistent performance with some devices and it's "so" "not necessary"
I'd like to see something "new generation" come along to replace the 510 connection. I'd bet it could be done better.
Duane
Actually I just realised @funkyrudi said a few thousandths and those are all a few hundredths So maybe you were taking into account the relative TCR, funky.
However the actual static resistance is in the hundreds, not thousands. Eg 0.03 for a KF4
So maybe you were taking into account the relative TCR, funky.However the actual static resistance is in the hundreds, not thousands. Eg 0.03 for a KF4
i was more more worried about severe errors in temperature rather than toxicity. As you so elegantly show above, errors in the resting resistance are compounded and more dramatically for low TCR wires. This is even worse if you are unsure what the TCR is for your wire (ie what grade of TI/Ni/SS etc
Edit: Post corrected to add in static resistance missed out on final calculation, thanks @funkyrudi
For completeness, here is an Ni200 coil with a 0.03 static resistance discrepancy. The difference is even worse than with Ti:
Ni200: Test for temperature detection inaccuracy when resistance is read incorrectly too high by 0.03Ω on a Ni coil of 0.10Ω
In the following lists values I typed are in normal text, values calculated are in bold.
Calculation 1:
For completeness, here is an Ni200 coil with a 0.03 static resistance discrepancy. The difference is even worse than with Ti:
Ni200: Test for temperature detection inaccuracy when resistance is read incorrectly too high by 0.03Ω on a Ni coil of 0.10Ω
In the following lists values I typed are in normal text, values calculated are in bold.
Calculation 1:
Checking the resistance rise for a Ni200 coil of 0.10Ω, increasing from 20°C to 232°C (450°F)
Calculation 2:- Resistivity: 0.0062 (Ni200)
- Starting temp: 20°C
- Ending temp: 232°C
- Starting resistance: 0.10Ω
- Ending resistance: 0.23144Ω
Checking the resistance rise for a Ni200 coil of 0.13Ω, increasing from 20°C to 232°C (450°F)
Calculation 3:- Resistivity: 0.0062 (Ni200)
- Starting temp: 20°C
- Ending temp: 232°C
- Starting resistance: 0.13Ω
- Ending resistance: 0.300872Ω
Checking the temperature rise on a Ni200 coil that is actually 0.10Ω but which is measured as 0.13Ω.
The coil is really 0.10Ω so when heated to 232/450° its resistance will to 0.23144Ω (calc 1). Which will be detected as 0.26144Ω (= 0.23144Ω + 0.03Ω static resistance)
But the mod thinks its starting resistance is 0.13Ω, so it calculates a rise to 0.26144Ω as being a temperature of 183°C / 361°F when the coil is actually at 232°C / 450°F.
This is an inaccuracy of 49°C / 89°F from a 0.03Ω delta on a Ni200 0.10Ω coil.
- Resistivity: 0.0062 (Ni200)
- Starting temp: 20°C
- Ending temp: 183 °C
- Starting resistance: 0.13Ω
- Ending resistance: 0.26144Ω (= 0.23144Ω + 0.03Ω static resistance)
The coil is really 0.10Ω so when heated to 232/450° its resistance will to 0.23144Ω (calc 1). Which will be detected as 0.26144Ω (= 0.23144Ω + 0.03Ω static resistance)
But the mod thinks its starting resistance is 0.13Ω, so it calculates a rise to 0.26144Ω as being a temperature of 183°C / 361°F when the coil is actually at 232°C / 450°F.
This is an inaccuracy of 49°C / 89°F from a 0.03Ω delta on a Ni200 0.10Ω coil.
Last edited:
Ah fair enough!
And yes you raise a good point - we can never be completely sure of the TCR. Well, maybe we can with Dicodes' NiFe30 because they both measured and supplied it! That is one advantage there.
With SS we are working in the range 0.00094 (SS304) - 0.00105 (Dicodes' generic value).
With Ti every source pretty much agrees on 0.0035, but we don't know 100% that's for Ti Gr1 or even if it varies - presumably it shouldn't for all the "pure" Ti grades (1-5) but again, this needs confirmation.
Even for Ni200 we have doubt - many places say 0.006, Dicodes say 0.0062, I saw one say 0.0058. Those are, I think, for pure 100% nickel. The one place I thought listed it for Ni200 I think said 0.005 - definitely too low compared to what we really see with actual Ni200 wire. I don't know why there is so much variance in measuring/providing a seemingly static figure of a known-spec wire, but there seems to be.
Which actually raises an interesting question for all the first-gen TC mods which have a hardcoded value. Which one did they pick? 0.006? 0.0062? Will this vary with manufacturer - probably!
Even more reason why being able to choose one's own value is of benefit to those who want to be able to make it exact - even with known quality, top grade Ni200. There must be some reason why all these sources quote different figures for seemingly the same exact wire at a stated purity, so maybe it can vary with measurement, with the exact wire (even at spec), who knows!
Not to mention @ndb70 's excellent point of being able to use TCR to account for and nullify static resistance.
(Of course none is this is required for a satisfactory vape, as most of the time we can just dial a temp and go and being somewhere within the margin of error is fine. But it is interesting to experiment with!)
He was talking of 0.0026 to 0.003 Ohm - I refered to these values. When I calculate it for 0.003 Ohm the temperature will be 228.29C. Okay 4 degrees, that´s more than I expected, but I could live with it. The temperature error on an Ni coil of 0.1 Ohm would be 11C. That`s again not what I expected, I expected a bigger error.
Thanks Tom
Btw: How can you write such a post in such a short time? Respect!!
Last edited:
Humm, well yes if it is 0.003 we have no problems, but originally he said:
@ndb70 can you confirm which is correct? 0.03 or 0.003?
You said 0.03 a couple of days ago, and 0.0026 today - which has the correct number of zeroes? Hundreds or thousands?
@ndb70 can you confirm which is correct? 0.03 or 0.003?
You said 0.03 a couple of days ago, and 0.0026 today - which has the correct number of zeroes?
Hundreds or thousands?
I think SS wire is one of the most flavourful one what I have tried. In the past I used it for microcoils on mech mods like many vapors in Hungary. But to do that you have to oxidize it what is not so easy like Kanthal. Probably it's not the safe way.
For TC I use 0.28mm for non contact coils on 2.5mm diameter. This a thinner wire what heats up quickly and doesn't need too much power.
I vape it on 210°C without any offset because it passed the water test with surprisingly good result (98-102°C). And it works really stable, much more stable than with Ni. The temperature protection works as I can see it in the mirror because I have a VS clone.
I will order some 317L to compare them.
Awesome to hear you like the flavour! I am a pretty poor judge of flavour, sadly :/ I'll definitely be interested to hear your comparisons of 316 vs 317, thanks!
So you've only tried spaced coils thus far? Any reason? My experience with contact was that it did work, after a bit. I think maybe it has to oxidise first, because the first pulses show weird resistances and then it seemed to work. Which actually is no different to Kanthal I suppose! At first it seemed weird/different but of course I am not used to watching live resistance jumps when pulsing Kanthal coils.
I've only tried two SS coils thus far, actually I am going to do one now and check it more closely.
I still haven't done this water test, that's another thing I guess I should try. You just get a coil wet then pulse it and check the temp readout is around 100°C?
And haha re the mirror! That is why I am really glad I have the VF as first SXK mod. It is so easy to watch the screen
When I was thinking of getting my second mod, I kept considering the Zero for example, but then I thought.. why not just get another flask and have dual battery and be able to actually see teh screen at all times?
I really like the new Hana Mod that SXK have announced but again it is single battery, screen on side.I could not cope with a screen-on-bottom VS I'm afraid
Well not for a testing mod, in general use I am sure it doesn't matter.What`s most important for me, by these calculations I got a more realistic feeling for the real effects of low static resistances. It doesn`t matter what is the right or wrong value. I got my lesson. Thanks
Two days after the K4 came out I had lots of problems with the Ohm reading, what was very good for studing the K4. At the end I got constant readings, but by lengthening the conductive spring I could lower the static resistance by 0,05 Ohm. I talked to Eugen the developer the next day and he promised to think about this problem. A month later everybody knew about the problem and SM made the golden spring, which helped a bit.
Two days after the K4 came out I had lots of problems with the Ohm reading, what was very good for studing the K4. At the end I got constant readings, but by lengthening the conductive spring I could lower the static resistance by 0,05 Ohm. I talked to Eugen the developer the next day and he promised to think about this problem. A month later everybody knew about the problem and SM made the golden spring, which helped a bit.
Wrong calculation
When we have a 0,4 Ohm coil and a static resistance of 0,04 Ohm and a set temperature of 232 C, the chip will expect a value of 0.76648 Ohm. But this value contains the static resistance, so we have a coil resistance of 0.72648 and the coil temperature will be 253.2C = 21C too much.
With the static resistance of 0.003 Ohm we would get 227.16C at the coil. This seems strange because in the first case the coil temperature increases and in the second case decreases. But I guess that`s right.
When we have a 0,4 Ohm coil and a static resistance of 0,04 Ohm and a set temperature of 232 C, the chip will expect a value of 0.76648 Ohm. But this value contains the static resistance, so we have a coil resistance of 0.72648 and the coil temperature will be 253.2C = 21C too much.
With the static resistance of 0.003 Ohm we would get 227.16C at the coil. This seems strange because in the first case the coil temperature increases and in the second case decreases. But I guess that`s right.
- Status
Similar threads
- Locked
- Locked
- Locked
