TC beyond Ni200: Nickel Purity, Dicodes; Ti, SS, Resistherm NiFe30; Coefficient of Resistance

[TheBloke]

@TheBloke, so I guess for the wet coil test you would wick with rayon and wet with vg(290°c bp)? Maybe have some form of controlled airflow like a small fan or maybe a small air compressor with a regulator? Maybe an airbrush compressor or small portable tire inflator? It'll be fun to see the results of your setup. I'm especially interested in your findings for 430ss and NiFe52. Both possible candidates for my evic.

Last time I used cotton, maybe I'll use Rayon this time (though I do have a lot more cotton available that I never use any more!)

I'll start with 50/50 juice because that's a reasonable average of what people use, but yes also vary it from 30% VG up to 100%

I have controlled airflow in the form of a a few sizes of small DC fans - like the kind in a PC. I don't have any of the other airflow items you listed. I did think about getting an air flow measurer, some of which can be had fairly cheaply, but didn't progress it yet. I think for the moment simply always using the same fan at the same voltage would be sufficient.

In past tests I simply directed the fan over the coil. In future tests I migth see if I can localise the airflow in some way, to make it a bit more like a real vape - ie a "chimney" of sorts, albeit probably much larger than an atomizer chimney.

Looking at the DNA40 chart I would definitely be able to detect that.

I can detect my vape getting hotter when the wick begins drying out and cooler when my mech misfires for a second in the middle of a vape (Stingray bad about this).

But do you think those variatiois you detect are as narrow as shown on the DNA 40 chart? The moment-to-moment fluctuations on that chart were never more than a few °C. It move across the range of 20°C in total, but that was over 2 or 3 minutes of continuous firing. It wasn't lurching about second to second.

In any case don't put too much store in that early test result with Ni200. I'll repeat the test with wet coil Titanium in a more controlled way and we'll see what it looks like then.

 

[f1vefour]

It dropped 16°C for a full second (more like low for a second), I'm certain could detect that. Not that it's a show stopper, just the low warmth would be noticeable.

*edit*
Those are minutes:seconds, I didn't realize. I thought it was seconds:splitsecond

 

[BigEgo]

Yeah we've looked at this a little before. I found some tungsten wire on eBay from Canada and was at first tempted to buy it. The big problem was resistance - lower than nickel! With the TCR also a little lower than Ni200, this would make for the least accurate wire of any, and likely even more annoying than Ni200 to use in practice.

The Canadian wire on eBay was 99.95% pure Tungsten and available in sizes up to 0.50/24G, however the price for thicker wire is vast: $US 43 for 10 foot of wire. And the resistance of the preferred thickness wire is unusably low, eg 0.30Ω/m for 24G.

Then recently @DeareN found this 99.5% Tungsten alloy from a German vaping vendor: BUJA-W74 resistance wire - InTaste

The BUJA-W74 heating wire is made of 99.5 % tungsten and features a very fast response time. Due to the low resistance in combination with the strong increase in resistance when heated the High Performance Wire is also ideal suitable for temperature control. The 0.30mm diameter allows the BUJA-W74 to be processed wonderfully.

The problems:

• Only available in 0.30mm / 29.5G
• Even with that thin wire, it's only 1.0Ω/m:
  • 30% lower than Ni200
  • Nearly 3 times lower than NiFe70
  • 6.6 times lower than Titanium
• Expensive - €13 for 5m: double the cost of Resistherm, many times the cost of Titanium/NiFe/SS/etc

So I would have to say that low resistance blights Tungsten in the same way it blights Ni200 - in fact even more so. It may well have some other advantages over Ni200 - inert, (perhaps) usability, certainly max temp - but given its high cost and/or limited thickness, and ultra low resistance, I've not been that bothered to try it out. I think at best it will be better than Ni200, but definitely not the other wires we use/are looking at.

If I ever see it available at some place I'm buying other things, or it shows up on a UK site at vaguely normal prices, I might throw a spool in for curiosity. But for now it appears a non-starter, at least in these pure/nearly pure forms.

Maybe there are lower % alloys that can increase the resistance while keeping (most of) the high temp maximums.


PS. As an aside, I'm equal parts amused and horrified to see that German site, In Taste, saying that "Due to the low resistance [Tungsten is] ideal[ly] suitable for temperature control." The exact opposite of correct! Low base resistance is an impediment to temperature control, not a benefit.

Yes, I thought the resistance could be a problem. It seems a better option would be a tungsten alloy of some sort.

Also, light bulbs are sealed with argon in order to keep the filament from being exposed to a potentially corrosive oxidating environment. This tells me that Tungsten may have higher than average oxidating properties, but I really don't know. We need a metallurgist.

 

[druckle]

Yeah we've looked at this a little before. I found some tungsten wire on eBay from Canada and was at first tempted to buy it. The big problem was resistance - lower than nickel! With the TCR also a little lower than Ni200, this would make for the least accurate wire of any, and likely even more annoying than Ni200 to use in practice.

The Canadian wire on eBay was 99.95% pure Tungsten and available in sizes up to 0.50/24G, however the price for thicker wire is vast: $US 43 for 10 foot of wire. And the resistance of the preferred thickness wire is unusably low, eg 0.30Ω/m for 24G.

Then recently @DeareN found this 99.5% Tungsten alloy from a German vaping vendor: BUJA-W74 resistance wire - InTaste

The BUJA-W74 heating wire is made of 99.5 % tungsten and features a very fast response time. Due to the low resistance in combination with the strong increase in resistance when heated the High Performance Wire is also ideal suitable for temperature control. The 0.30mm diameter allows the BUJA-W74 to be processed wonderfully.

The problems:

• Only available in 0.30mm / 29.5G
• Even with that thin wire, it's only 1.0Ω/m:
  • 30% lower than Ni200
  • Nearly 3 times lower than NiFe70
  • 6.6 times lower than Titanium
• Expensive - €13 for 5m: double the cost of Resistherm, many times the cost of Titanium/NiFe/SS/etc

So I would have to say that low resistance blights Tungsten in the same way it blights Ni200 - in fact even more so. It may well have some other advantages over Ni200 - inert, (perhaps) usability, certainly max temp - but given its high cost and/or limited thickness, and ultra low resistance, I've not been that bothered to try it out. I think at best it will be better than Ni200, but definitely not the other wires we use/are looking at.

If I ever see it available at some place I'm buying other things, or it shows up on a UK site at vaguely normal prices, I might throw a spool in for curiosity. But for now it appears a non-starter, at least in these pure/nearly pure forms.

Maybe there are lower % alloys that can increase the resistance while keeping (most of) the high temp maximums.


PS. As an aside, I'm equal parts amused and horrified to see that German site, In Taste, saying that "Due to the low resistance [Tungsten is] ideal[ly] suitable for temperature control." The exact opposite of correct! Low base resistance is an impediment to temperature control, not a benefit.

Tungsten oxidizes like titanium. It only tolerates the high temperatures in incandescent bulbs because it is in an oxygen free atomosphere. I think it's near useless for vaping because of it's low resistance,and high cost among other things.

Duane

 

[tchavei]

That's what I thought/hoped at first, as dry coil testing is very much simpler and quicker. All my early tests were dry only.

But it isn't working out like that in practice. Some mods show good accuracy in dry coil, like the DNA 40. Other mods show surprisingly inaccurate results, like the SX Mini M which I mentioned last night: it will cut all power after 4 seconds if it detects dry coil, and even trying to control for that it fluctuates around a lot. It's subjectively very accurate in normal vaping, but not on the dry coil charts. So I do not feel the dry coil chart does it justice. The Joyetech is an even stronger example: would you subjectively say the Joyetech has a completely unpredictable, wildly fluctuating TC vape? I wouldn't, but that's what the dry coil results I got showed.

Ultimately the wet coil test is the 'real' test - it's the test of the vaping we actually do. Dry coil is artificial, and may not be a good representation of how the mods operate. It hides or at least reduces the importance of the mod's power algorithm and the frequency of its calculations, and it possibly operates in different conditions to the circumstances that the mod makers have assumed. And on several mods it definitely is giving results that don't feel like they at all represent what the mod actually TC vapes like.

Believe me I'd rather just do dry tests. But if it isn't guaranteed to give results applicable to the real world, there doesn't seem much point. So I'm going to do pairs of tests, wet and dry. In some cases both results will be interesting - like for the DNA 40, and therefore presumably also the 200, where the dry coil case is the 'best case' result and the wet shows how it differs from best case when in 'real' vaping conditions. For other mods, the dry coil test may be discarded because it clearly doesn't show what happens during a real vape.

Don't know about the dna 40 but the dna 200, at 580C and a dry coil will pulse VERY slowly like a car's turn signal light.

Not sure it's the high temperature setting, the fake doubled TCR or really the dna 200 refresh rate on a dry coil but I was surprised I could visually see it pulse in an almost 1 sec frequency.

This doesn't happen with a wet coil (at least not noted) because the vape is super smooth.

Regards
Tony

Sent from my keyboard through my phone or something like that.

 

[TheBloke]

Don't know about the dna 40 but the dna 200, at 580C and a dry coil will pulse VERY slowly like a car's turn signal light.

Not sure it's the high temperature setting, the fake doubled TCR or really the dna 200 refresh rate on a dry coil but I was surprised I could visually see it pulse in an almost 1 sec frequency.

This doesn't happen with a wet coil (at least not noted) because the vape is super smooth.

Yeah it's very surprising to think the temperature could be fluctuating as much as a visible pulsing of the coil seems to suggest. 600°C is way higher than the mod was ever designed for or tested at, and perhaps the coil responds differently at such temperatures - X amount of power giving a higher or lower than anticipated changed in resistance/temperature. Unless it's possible for visual colour changes to happen within a very narrow temperature difference, like a few degrees? Perhaps there are "borderline" temperatures which will show a large difference in coil colour within just a few °C difference in temp?

Anyway my 700°C probe will be with me next week so I shall investigate it then.

 

[TheBloke]

It dropped 16°C for a full second (more like low for a second), I'm certain could detect that. Not that it's a show stopper, just the low warmth would be noticeable.

*edit*
Those are minutes:seconds, I didn't realize. I thought it was seconds:splitsecond

Yeah sorry I just threw the graph up quickly without formatting - it's just the time stamp from the thermocouple log. When I do graphs properly I convert that axis to seconds. That whole graph is a period of 3 minutes 40 seconds.

Anyway let's not put too much store in that one graph, it was only meant as an example of what I'd seen in the past and what sort of data can be produced. The future results will be more controlled. And not with Ni200!

 

[dsidab81]

Sorry to be a pain, but I'm not seeing it in the TCR spreadsheet or in this massive thread. I just ordered some of the 28g SS 430 from unkamen, and I'm looking for a DNA 200 TCR curve? At the moment I've used the custom portion of escribe to input the TCR or .0014...curious if anyone has anything more?

 

[Devilon]

Sorry to be a pain, but I'm not seeing it in the TCR spreadsheet or in this massive thread. I just ordered some of the 28g SS 430 from unkamen, and I'm looking for a DNA 200 TCR curve? At the moment I've used the custom portion of escribe to input the TCR or .0014...curious if anyone has anything more?

Is this the one you are looking for High TCR Alloys

 

[dsidab81]

@Devilon Sorry that sheet has stainless 304 and 316. Curious if anyone has anything other than the multiplier for stainless 430. Thanks for the quick reply!

 

[TheBloke]

Sorry to be a pain, but I'm not seeing it in the TCR spreadsheet or in this massive thread. I just ordered some of the 28g SS 430 from unkamen, and I'm looking for a DNA 200 TCR curve? At the moment I've used the custom portion of escribe to input the TCR or .0014...curious if anyone has anything more?

You're not missing it, we don't have that added to any resources yet.

@balazsk has done the most recent work on it. Here is a graph he prepared showing SS 430 and 410, you can use this to create your DNA 200 curve. You'll have to guess the exact position on the temperature axis, and convert this to resistance factors.

A simpler way to use for now: Just use a single TCR of 0.00138, which will be exactly accurate at 230°C / 450°F and more than good enough in the rest of the vaping range.

If you normally vape higher or lower than that, you could adjust the TCR down slightly according to where you think the line is on the graph. But tiny differences either way are not going to make a vast difference.

I have made more calculations and it seems that type 410 is better than 430.

EDIT: reposting the graph image because apparently a quote doesn't show it inline





I do not know the source for the 410/430 data, @balazsk said that @vapealone posted a link to a datasheet that had SS 410 and SS 430, but I can't now find it searching the thread (doesn't come up searching for '410' or '430') The data sheets I have found for 410 and 430 did not have TCR/TFR information.

@vapealone do you think you could add 430 to the spreadsheet, now this wire is in active use?

I will keep searching the thread and google trying to find the source sheet but hopefully vapealone or balazsk can repost it soon.

 

[dsidab81]

@TheBloke Somehow I missed that chart - or at least did not see the SS 430 line. I think this will get me close enough.
Thanks a ton!!

 

[TheBloke]

No worries - credit to @balazsk and @vapealone for the actual work!

I just re-read your message and saw you only ordered it, not received it. I am sure by the time you have received it, we will have a proper DNA 200 curve file.

 

[balazsk]

You're not missing it, we don't have that added to any resources yet.

@balazsk has done the most recent work on it. Here is a graph he prepared showing SS 430 and 410, you can use this to create your DNA 200 curve. You'll have to guess the exact position on the temperature axis, and convert this to resistance factors.

A simpler way to use for now: Just use a single TCR of 0.00138, which will be exactly accurate at 230°C / 450°F and more than good enough in the rest of the vaping range.

If you normally vape higher or lower than that, you could adjust the TCR down slightly according to where you think the line is on the graph. But tiny differences either way are not going to make a vast difference.



EDIT: reposting the graph image because apparently a quote doesn't show it inline





I do not know the source for the 410/430 data, @balazsk said that @vapealone posted a link to a datasheet that had SS 410 and SS 430, but I can't now find it searching the thread (doesn't come up searching for '410' or '430') The data sheets I have found for 410 and 430 did not have TCR/TFR information.

@vapealone do you think you could add 430 to the spreadsheet, now this wire is in active use?

I will keep searching the thread and google trying to find the source sheet but hopefully vapealone or balazsk can repost it soon.

You can find the report about SS types here: http://dtic.mil/dtic/tr/fulltext/u2/a129160.pdf
@vapealone has posted it originally.

 

[jazzvaper]

You can find the report about SS types here: http://dtic.mil/dtic/tr/fulltext/u2/a129160.pdf
@vapealone has posted it originally.

Thank you @balazsk, and, very timely. My wire has arrived. Now I can use it with some confidence. And, a quick question, what is text from which these reports arise. I have a very good science library nearby.

BTW, I read this thread on my phone earlier today. Looking for it once home the thread seemed to disappear. I thought I might have been banned. Nope, my finger slid too quickly in Tapatalk. Home again...ahhh!

 

[Mactavish]

Curious, first time trying an Atlantis Triton pre-built .4 ohm stainless steel coil on my IPV D2 mod. It has settings for Nickel and Titanium, but NO SS setting. These coils are marketed for use in non TC MODS, so I'm using it in power mode/non TC. Can these coils be used in both TC mods and non TC mods, assuming you would need a SS offset and a mod that can set one. See my confusion? I see SS as a TC coil, but they sell them for any mods.

 

[dsidab81]

SS doesn't have such a low starting resistance and steep climb as temp increases .. So yes you can use it for both.

 

[dsidab81]

Some of the mods now have tcr offsets.. And you could likely use Ti mode and manipulate the temp. Much like people first did with Ti wire when ni200 was the only tc option on mods

 

[Mactavish]

SS doesn't have such a low starting resistance and steep climb as temp increases .. So yes you can use it for both.

They don't market these coils for TC mods, or even mention it, so which application would be more accurate?

 

[dsidab81]

Guess I can't speak authoritatively, but I've heard of guys using ss on mechs for awhile. So maybe power mode would be better unless you could alter the tcr to match...