I don't base my decision on just being grade 2. But I don't favor companies that take something ordinary then act as if they made it different or that it's better than something that is essentially no different but charge a high price for it. After all the high price is something I don't mind if it is truly a different product that is superior. It's just taking an existing product, putting your logo on it, making some fancy wording and trickery to average consumers, and charging a fortune.
TC beyond Ni200: Nickel Purity, Dicodes; Ti, SS, Resistherm NiFe30; Coefficient of Resistance
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Regarding unkamen supply, I contacted them regarding stainless steel, and they have said they will do order of custom lengths as well.
Is that 316L, or 304? They unfortunately do not carry 317L, and while their 316L prices were good, I do seem to recall their 304 prices were lower.
My bad, it's two hundred feet of 28awg SS for five bucks.
28 gauge Stainless Steel Wire - Nickel Free - 200 Feet - Introductory – Unkamen Supplies
28 gauge Stainless Steel Wire - Nickel Free - 200 Feet - Introductory – Unkamen Supplies
Does Unkamen say what the specification is for the stainless wire you referenced? If it is nickel free it is what is called a martensitic stainless (the most common of which is type 410). I do not know the TCR for any of the martensitic stainless materials off hand but I would suspect that it is quite different than the 300 series wires which have been discussed here. The 300 series wires contain nickel and are generally austenitic materials.
I suggest that before ordering stainless steels in various types (there are MANY types of steels referred to as stainless) it is important to do some homework to be sure that the properties are well documented and well understood for vaping.
Duane
I saw that Unkamen has a custom request/order form. I don't recall anyone mention they had submitted a request, so I went ahead and put one in for NiFe52. I don't know if there's any possible jewelry applications for it and if not, he may not be interested in picking it up, but maybe he will...
The Cindas report contains data about stainless steel type 410. The report was linked by @vapealone.
SS410 has a nice linear TFR curve, higher TCR (0.00156), but a bit lower resistance on room temperature.
There is also data about 430 that is similar to 410 and this type can be ordered from Unkamen. Maybe I should, together with some niobium.
SS410 has a nice linear TFR curve, higher TCR (0.00156), but a bit lower resistance on room temperature.
There is also data about 430 that is similar to 410 and this type can be ordered from Unkamen. Maybe I should, together with some niobium.
The Cindas report contains data about stainless steel type 410. The report was linked by @vapealone.
SS410 has a nice linear TFR curve, higher TCR (0.00156), but a bit lower resistance on room temperature.
There is also data about 430 that is similar to 410 and this type can be ordered from Unkamen. Maybe I should, together with some niobium.
Wow! 150 does sound very interesting.
Not least because it could be the key to answering a question that @Mad Scientist and I talked around earlier today:
When exactly does TCR matter for accurate TC on mods?
We know that SS's ~ 0.001 is 'low', and Dicodes describe this as accurate to nearest 30°C, versus nearest 5°C for Ni200. We know that 0.0032 (Resistherm NiFe30) and 0.0035 (Titanium) and above are fine, from our own experiences and testing.
So when does 'fine' change to 'low'?
I'm wondering if this SS 410/430 could a the 'missing link' wire, the one that shows us the lowest TCR we can use with good accuracy.
But now I'm also wondering - how did Dicodes decide that SS @ 0.00105 (the TCR they give for 'Stainless Steel', unspecified type, in their guide) is accurate to nearest 30°C, but Ni200 to 5°C?
A quick TCR calculation:
- Accuracy of high-end TC mod: 1 milliohm
- TCR: 0.00105
- Temperature: 20°C -> 220°C (200°C increase)
- Base resistance: 1.0Ω
- End resistance: 1.21Ω
- Delta: 0.21Ω = 210 milliohm
- 200°C / 210 mΩ = 0.95°C/mΩ
- Accurate to nearest 1°C?
- Base resistance: 0.20Ω
- End resistance: 0.242Ω
- Delta: 0.042Ω = 42 milliohm
- 200°C / 42 mΩ = 4.76°C/mΩ
- Accurate to nearest 5°C?
Even if they're factoring in some SR, those figures are a long way off.
Now I wish I had done proper temp probing with SS on the Dicodes, and DNA 200 for that matter. I will do that ASAP.
But I do feel, from subjective vape experience, that SS is not as accurate as the other wires we talk about. I often can't set a coil at the usual temps I set other coils : I might set 210-215°C instead of 230-240°C, for example.
It feels, from subjective experience, to match what Dicodes described: 'repeatable', not 'accurate'.
Is there some other factor I'm neglecting? Have I muffed the maths?
Anyway, yes of course you should get some, @balazsk ! I know I'm going to
We must vape all the wires! But seriously, 0.00150 is interesting - if it makes SS half way accurate (assuming it can't be already), then that's another usable, dry-burnable wire, and one that has no nickel and is cheap and strong. At the least it's another option worth considering.
Not to mention that it might bring SS into range of being usable with temperature offset on a Titanium mod; 150 down from 350 is not such a huge difference, especially if it's very linear.
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Wow! 150 does sound very interesting.
Not least because it could be the key to answering a question that @Mad Scientist and I talked around earlier today:
When exactly does TCR matter for accurate TC on mods?
We know that SS's ~ 0.001 is 'low', and Dicodes describe this as accurate to nearest 30°C, versus nearest 5°C for Ni200. We know that 0.0032 (Resistherm NiFe30) and 0.0035 (Titanium) and above are fine, from our own experiences and testing.
So when does 'fine' change to 'low'?
I'm wondering if this SS 410/430 could a the 'missing link' wire, the one that shows us the lowest TCR we can use with good accuracy.
But now I'm also wondering - how did Dicodes decide that SS @ 0.00105 (the TCR they give for 'Stainless Steel', unspecified type, in their guide) is accurate to nearest 30°C, but Ni200 to 5°C?
A quick TCR calculation:
What am I missing here? Why, on a milli-ohm mod, isn't Stainless Steel accurate to nearest 5°C with a 0.20Ω base resistance coil and up to 1°C at a 1.0Ω coil? Why did Dicodes state it as nearest 30°C?
- Accuracy of high-end TC mod: 1 milliohm
- TCR: 0.00105
- Temperature: 20°C -> 220°C (200°C increase)
- Base resistance: 1.0Ω
- End resistance: 1.21Ω
- Delta: 0.21Ω = 210 milliohm
- 200°C / 210 mΩ = 0.95°C/mΩ
- Accurate to nearest 1°C?
- Base resistance: 0.20Ω
- End resistance: 0.242Ω
- Delta: 0.042Ω = 42 milliohm
- 200°C / 42 mΩ = 4.76°C/mΩ
- Accurate to nearest 5°C?
Now I wish I had done proper temp probing with SS on the Dicodes, and DNA 200 for that matter. I will do that ASAP.
But I do feel, from subjective vape experience, that SS is not as accurate as the other wires we talk about. I often can't set a coil at the usual temps I set other coils : I might set 210-215°C instead of 230-240°C, for example.
It feels, from subjective experience, to match what Dicodes described: 'repeatable', not 'accurate'.
Is there some other factor I'm neglecting? Have I muffed the maths?
Anyway, yes of course you should get some, @balazsk ! I know I'm going to
But seriously, 0.00150 is interesting - if it makes SS half way accurate (assuming it can't be already), then that's another usable, dry-burnable wire, and one that has no nickel and is cheap and strong. At the least it's another option worth considering.
Not to mention that it might bring SS into range of being usable with temperature offset on a Titanium mod; 150 down from 350 is not such a huge difference, especially if it's very linear.
I think accurate, stable, repeatable measurements in this application are closer to a 10mOhm resolution rather than 1 in terms of order of magnitude (and even that isn't easy). That may explain the 30 C temp resolution window, depending on base resistance. But we will test!
I just went back to Dicodes' Application Note For Temp Controlled Vaping, and they say this:
Now I understand - they are using a 0.1Ω base coil. Which is indeed 10°C per milliohm. Hence they can easily come to 30°C, based on an assumed minimum SR of about 0.003Ω.
But.. who the hell builds a 0.1Ω Stainless Steel coil? With a realistic SS coil, 0.50Ω (8-9 wraps x 3.0mm ID of 0.45mm/25G SS317) we're talking 2°C per mΩ.
So their 10mΩ estimate of varying SR - not unreasonable - is now 20°C inaccuracy; also not unreasonable!
In terms of what they say, we mustn't forget that Dicodes are trying to sell their own Resistherm; they have an agenda to make it out to look the best wire. I hope that hasn't caused them to deliberately choose bad examples.. but it sure seem like they have chosen a very bad example for SS.
Anyway.. maybe SS ain't so bad after all? Even at 0.001?
I still have my own subjective results which seemed to give poorer results. But, being subjective, can't be counted on. Maybe I just assumed it'd be less accurate and saw what I expected
Yes, certainly taking into account SR. But even then, with the right base resistance, it seems we should only be talking acceptable levels of inaccuracy. 20°C odd.
Testing is indeed the key!
And assumptions, the sworn enemy of testing, are bad. My bad, just trusting Dicodes all this time
(I've also polluted my results by doing a lot of SS vaping on the SXK, which certainly are inaccurate for SS but then are very likely not doing mΩ accurate resistance readings.)
For example stainless steel wire has a coefficient of about 10.5%/100°C ..
Of course the lower temperature coefficient results in smaller absolute temperature measurement accuracy. 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. ...
To enable an accurate temperature measurement, an extremely precise resistance measurement is mandatory. The dicodes electronic is able to measure the resistance to an accuracy of 1mOhm (1/1000 of an Ohm). There is additional explanatory need: The electronic not only measures the heater-winding, but the resistance of the whole atomizer built including all contact resistances, mainly the (screw-) fixation of the wire and the 5-10 thread. The thermal coefficients of those contact resistances are dramatically different to the one of the wire. Moreover little changes in the mechanical arrangement, e.g. the subsequent fastening of the atomizer, or thermal bracing, which are created by the heating, can easily create changes of the resistance of several mOhms (milli-Ohms, 1/1000 Ohm).
Exemplification: Assume a stainless steel heater wire has 0.1 Ohm of resistance at 20°C. With the coefficient of 10%/100°, a measured change of 1mOhm would mean a 10°C temperature change! If the atomizer was fastened again or due to thermal bracing, the resulting resistance change of for example 10mOhms, increase the measurement error to 100°C.
Of course the lower temperature coefficient results in smaller absolute temperature measurement accuracy. 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. ...
To enable an accurate temperature measurement, an extremely precise resistance measurement is mandatory. The dicodes electronic is able to measure the resistance to an accuracy of 1mOhm (1/1000 of an Ohm). There is additional explanatory need: The electronic not only measures the heater-winding, but the resistance of the whole atomizer built including all contact resistances, mainly the (screw-) fixation of the wire and the 5-10 thread. The thermal coefficients of those contact resistances are dramatically different to the one of the wire. Moreover little changes in the mechanical arrangement, e.g. the subsequent fastening of the atomizer, or thermal bracing, which are created by the heating, can easily create changes of the resistance of several mOhms (milli-Ohms, 1/1000 Ohm).
Exemplification: Assume a stainless steel heater wire has 0.1 Ohm of resistance at 20°C. With the coefficient of 10%/100°, a measured change of 1mOhm would mean a 10°C temperature change! If the atomizer was fastened again or due to thermal bracing, the resulting resistance change of for example 10mOhms, increase the measurement error to 100°C.
Now I understand - they are using a 0.1Ω base coil. Which is indeed 10°C per milliohm. Hence they can easily come to 30°C, based on an assumed minimum SR of about 0.003Ω.
But.. who the hell builds a 0.1Ω Stainless Steel coil? With a realistic SS coil, 0.50Ω (8-9 wraps x 3.0mm ID of 0.45mm/25G SS317) we're talking 2°C per mΩ.
So their 10mΩ estimate of varying SR - not unreasonable - is now 20°C inaccuracy; also not unreasonable!
In terms of what they say, we mustn't forget that Dicodes are trying to sell their own Resistherm; they have an agenda to make it out to look the best wire. I hope that hasn't caused them to deliberately choose bad examples.. but it sure seem like they have chosen a very bad example for SS.
Anyway.. maybe SS ain't so bad after all? Even at 0.001?
I still have my own subjective results which seemed to give poorer results. But, being subjective, can't be counted on. Maybe I just assumed it'd be less accurate and saw what I expected
I think accurate, stable, repeatable measurements in this application are closer to a 10mOhm resolution rather than 1 in terms of order of magnitude (and even that isn't easy). That may explain the 30 C temp resolution window, depending on base resistance. But we will test!
Yes, certainly taking into account SR. But even then, with the right base resistance, it seems we should only be talking acceptable levels of inaccuracy. 20°C odd.
Testing is indeed the key!
And assumptions, the sworn enemy of testing, are bad. My bad, just trusting Dicodes all this time
(I've also polluted my results by doing a lot of SS vaping on the SXK, which certainly are inaccurate for SS but then are very likely not doing mΩ accurate resistance readings.)
Wow! 150 does sound very interesting.
Not least because it could be the key to answering a question that @Mad Scientist and I talked around earlier today:
When exactly does TCR matter for accurate TC on mods?
We know that SS's ~ 0.001 is 'low', and Dicodes describe this as accurate to nearest 30°C, versus nearest 5°C for Ni200. We know that 0.0032 (Resistherm NiFe30) and 0.0035 (Titanium) and above are fine, from our own experiences and testing.
So when does 'fine' change to 'low'?
I'm wondering if this SS 410/430 could a the 'missing link' wire, the one that shows us the lowest TCR we can use with good accuracy.
But now I'm also wondering - how did Dicodes decide that SS @ 0.00105 (the TCR they give for 'Stainless Steel', unspecified type, in their guide) is accurate to nearest 30°C, but Ni200 to 5°C?
A quick TCR calculation:
What am I missing here? Why, on a milli-ohm mod, isn't Stainless Steel accurate to nearest 5°C with a 0.20Ω base resistance coil and up to 1°C at a 1.0Ω coil? Why did Dicodes state it as nearest 30°C?
- Accuracy of high-end TC mod: 1 milliohm
- TCR: 0.00105
- Temperature: 20°C -> 220°C (200°C increase)
- Base resistance: 1.0Ω
- End resistance: 1.21Ω
- Delta: 0.21Ω = 210 milliohm
- 200°C / 210 mΩ = 0.95°C/mΩ
- Accurate to nearest 1°C?
- Base resistance: 0.20Ω
- End resistance: 0.242Ω
- Delta: 0.042Ω = 42 milliohm
- 200°C / 42 mΩ = 4.76°C/mΩ
- Accurate to nearest 5°C?
Even if they're factoring in some SR, those figures are a long way off.
Now I wish I had done proper temp probing with SS on the Dicodes, and DNA 200 for that matter. I will do that ASAP.
But I do feel, from subjective vape experience, that SS is not as accurate as the other wires we talk about. I often can't set a coil at the usual temps I set other coils : I might set 210-215°C instead of 230-240°C, for example.
It feels, from subjective experience, to match what Dicodes described: 'repeatable', not 'accurate'.
Is there some other factor I'm neglecting? Have I muffed the maths?
Anyway, yes of course you should get some, @balazsk ! I know I'm going to
But seriously, 0.00150 is interesting - if it makes SS half way accurate (assuming it can't be already), then that's another usable, dry-burnable wire, and one that has no nickel and is cheap and strong. At the least it's another option worth considering.
Not to mention that it might bring SS into range of being usable with temperature offset on a Titanium mod; 150 down from 350 is not such a huge difference, especially if it's very linear.
I admire your resolve Tom. From just one specification agency ....................."Stainless steel's resistance to corrosion and staining, low maintenance and familiar lustre make it an ideal material for many applications. There are over 150 grades of stainless steel, of which fifteen are most commonly used."
Actually there are many more than that if specialty materials are considered.
Are you looking for a guaranteed (unpaid) lifetime job?
Seriously if we came up with a definitive set of property goals and $$$ it would be easy for someone with laboratory melting / process equipment to meet our specs. It's probably far from necessary but some graduate student somewhere would likely like the challenge.
Duane
Haha OK, maybe I exaggerated a teeny tiny bit on all Representative samples? I've already got three SS', though have only actually vaped on one so far. I think I'll use the 304 for my next SS tests. But I can definitely justify a new SS with 50% more TCR.
But now you're talking.. custom made vaping wires, by vapers, for vapers, zero technobabble guaranteed!
It'll be like being in an ice cream parlour. "Ooh, I want lots of iron, a bit of chrome, 0.8% aluminium, and give me just a little sprinkling of manganese!"
I'm still fairly sure NiFes are going to win the day overall, at least for my preferences, but SS is theoretically looking much more interesting to me now - doubly so if we can get it at 0.0015. I know from experience it's just lovely to work with - it's strong, it coils exactly to the ID of your rod, you can adjust it easily, you can dry burn it. It's great. And if nickel sensitivities do still prove problematic at 52% and 70% Ni, then that's another advantage for a lot of people.
Of course, this all might be a short-term dead-end; six months down the line, assuming we're not all in prison for Illegal Vaping, we might well all be vaping on the Kayfun v5-TC, Lemo 4-TC, Aqua v4 featuring ATTACK (Aqua Temperature Technology Actuated by Chrome Knobs).. all with Innokin in-tank TC sensors. Then what will I do? We'll all be back to Kanthal
But for now, yeah, I want all* the wires!
*some
Representative samples? I've already got three SS', though have only actually vaped on one so far. I think I'll use the 304 for my next SS tests. But I can definitely justify a new SS with 50% more TCR.But now you're talking.. custom made vaping wires, by vapers, for vapers, zero technobabble guaranteed!
It'll be like being in an ice cream parlour. "Ooh, I want lots of iron, a bit of chrome, 0.8% aluminium, and give me just a little sprinkling of manganese!"
I'm still fairly sure NiFes are going to win the day overall, at least for my preferences, but SS is theoretically looking much more interesting to me now - doubly so if we can get it at 0.0015. I know from experience it's just lovely to work with - it's strong, it coils exactly to the ID of your rod, you can adjust it easily, you can dry burn it. It's great. And if nickel sensitivities do still prove problematic at 52% and 70% Ni, then that's another advantage for a lot of people.
Of course, this all might be a short-term dead-end; six months down the line, assuming we're not all in prison for Illegal Vaping, we might well all be vaping on the Kayfun v5-TC, Lemo 4-TC, Aqua v4 featuring ATTACK (Aqua Temperature Technology Actuated by Chrome Knobs).. all with Innokin in-tank TC sensors. Then what will I do? We'll all be back to Kanthal
But for now, yeah, I want all* the wires!
*some
Back to Dicodes and their Application Note, I just noticed that they do follow up the above paragraphs with this :
As the Nickel wire has much higher conductivity, a usable heater winding will have between 0.1 to 0.2 Ohms, whereas a stainless steel wire should have between 1 and 2 Ohms when using temperature controlled vaping.
So they correctly point out that SS will have a much higher resistance - though 2.0Ω is much higher than I would ever use; even 1.0Ω is a stretch.
What they completely fail to point out is that this utterly invalidates their earlier statement about SS' inaccuracy vs Ni200.
They compare SS to Ni200 @ 0.10Ω, showing that 10mOhm of SR equates to 100°C inaccuracy versus 16°C. Then they note that the SS coil will actually be more like 1.0Ω, but fail to point out that that would make the inaccuracy of the SS coil 10°C, less than Ni200's 16°C!
They've got all the right points in there but in slightly the wrong order, leading to a very misleading conclusion made before all the facts are discussed.
Very odd.
Of course after that they then go on to recommend Resistherm:
(We recommend to use the dicodes wire, with a temperature coefficient of 32%/100° and a resistance between 0.5 and 1.5 Ohms. This wire provides an optimal compromise between temperature accuracy, thermal mass and vape generating surface.)
Yeah, optimal for Dicodes maybe, when we pay €13/10m for it..
Oh, and since when has 29G been an 'optimal vape generating surface'
Bad Dicodes, bad. Drop your overpriced wire - or at least stop promoting it disingenuously - and concentrate on your lovely mods. Then we can be friends again.
Bad Dicodes, bad. Drop your overpriced wire - or at least stop promoting it disingenuously - and concentrate on your lovely mods. Then we can be friends again.
I just got an IPV D2 in and have been messing around with a nickel build. My build is 0.087 at room temperature (not sure of the temp in here, but it's between 65-75F). I have it set to 450F. Whenever I vape it, the resistance maxes out at .20 to .21. By my calculations this would put it closer to 500F than 450.
Is my math wrong or can anyone confirm?
Is my math wrong or can anyone confirm?
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