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

[tchavei]

so sorry i'm not very clear, and maybe im making it too complicated for myself.

tony suggested setting a tcr value "Just program a profile with a 0.007 TCR" (i know i can do that with escribe custom wire setting). when i do that, i see that its just a straight line with 3 temp data points (-100, 70, 800) and not 7 (-100, 0, 70, 200, 400, 600, 800).

so if for instance i buy some ss430 from unkaman, and i wanted an accurate tcr csv for that particular wire, should i just create a custom profile, click "special" and type in 0.0014 and live with that (-100, 70, 800). or, should i somehow figure out what the other temp points are and create a custom profile from that?

i hope im not digging myself deeper, so sorry, and thanks so much for trying to help.

Remember that the tcr I gave is for "dry cleaning service" only. Don't want somebody try to vape on that

FYI @jmarkus regarding the "heat Titanium coil to 600°C" thing - the correct TCR is 0.00725, not 0.007 - that will give 600°C for Titanium on a mod setting of 300°C.

Yeah but it glows just a little too much for my taste so I reduced it a little to give a little extra headroom and maybe taking the static resistance of the atty into account. It will still glow at 0.007 and 300C although the real temperature will be under 600C

Regards
Tony

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

 

[gorman]

FYI @jmarkus regarding the "heat Titanium coil to 600°C" thing - the correct TCR is 0.00725, not 0.007 - that will give 600°C for Titanium on a mod setting of 300°C.

That would be 83 on a Reliant, right?

 

[druckle]

Remember that the tcr I gave is for "dry cleaning service" only. Don't want somebody try to vape on that

Yeah but it glows just a little too much for my taste so I reduced it a little to give a little extra headroom and maybe taking the static resistance of the atty into account. It will still glow at 0.007 and 300C although the real temperature will be under 600C

Regards
Tony

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

Tony it sounds as if you came to the same conclusion as me. The original 0.00725 TCR gave a little hotter coil temp than I thought necessary. I'll try your 0.007 and see how that goes. The original number worked fine but probably got a little hotter than necessary.

Duane

 

[balazsk]

Tony it sounds as if you came to the same conclusion as me. The original 0.00725 TCR gave a little hotter coil temp than I thought necessary. I'll try your 0.007 and see how that goes. The original number worked fine but probably got a little hotter than necessary.

Duane

Yes, it is true. The reason is that the coil is dry and the temperature control algorithm is not fast enough for this job. It has been optimized for vaping where the coil is cooled by liquid and air. The temperature pulses and the coil glows up rhythmically when it is dry.
Therefore lower TCR or temperature is needed to keep the wire under 600°C.

 

[TheBloke]

So the tfr is just a multiplication factor from base res?

Yes exactly. So if you imagine using it with a 1.0Ω base resistance coil, the numbers on the Resistance Factor would be the resistance itself at that temperature. For other resistances, multiply as appropriate.

That would be 83 on a Reliant, right?

Yes in theory! You might want to set it a bit lower for now, both because of what Tony and Duane are saying, and just until I validate the scale does work like I calculated.

Yes, it is true. The reason is that the coil is dry and the temperature control algorithm is not fast enough for this job. It has been optimized for vaping where the coil is cooled by liquid and air. The temperature pulses and the coil glows up rhythmically when it is dry.
Therefore lower TCR or temperature is needed to keep the wire under 600°C.

I need to test this on the DNA 200, but I doubt this is true. It is not my experience with actual temperature testing on the DNA 40 on dry coils - which form the majority of my temp testing to date on all mods, as it's so much easier than wet coils with airflow. The DNA 40 never, ever overshoots, and nor do most mods I've tested.

The DNA 200 could be configured with up to 200W pre-heat, which could perhaps make a difference. Then again on the 40, it seems smart about not applying the pre-heat, or not all of it, to make it not overshoot. So I would be surprised if it just flung up to 200W at it regardless of how close it was getting to temp.

Edit: to be clear, the DNA 40 with Ni200 did fluctuate in a range of up to 3°C higher or 3°C lower than the configured temp, but I consider this within the expected, acceptable range. Plus that's Ni200, the least accurate material. I consider an overshoot to be >10°C over the target temp, which I have seen on some mods eg the Joyetech Evic, usually at the start of the pulse and probably associated with unrestricted pre-heat.

My theory on the overshoot is that either:
a) It's maintaining at 600 just fine, and it's just that the glow is more than they're expecting so it seems more than is needed when it's actually accurate
b) if it is actually overshooting, then there must be a fair bit of SR as Tony said.

Certainly it's a good idea to set it a little lower than theoretically required, as the cleaning differences from coming a bit under 600°C will be minimal, whereas the effect on the wire from going a bit over could be more major.

I'll try and test it, but might not be able to easily do so at 600°C as my good probes aren't rated for that and the probes I have that are are sucky, very low response time ones.

But I will certainly be able to validate the (lack of) overshoot at lower temps with the DNA 200, like I've already seen on the 40 and other mods.

 

[balazsk]

.



I need to test this on the DNA 200, but I doubt this is true. It is not my experience with actual temperature testing on the DNA 40 on dry coils - which form the majority of my temp testing to date on all mods, as it's so much easier than wet coils with airflow. The DNA 40 never, ever overshoots, and nor do most mods I've tested.

The DNA 200 could be configured with up to 200W pre-heat, which could perhaps make a difference. Then again on the 40, it seems smart about not applying the pre-heat, or not all of it, to make it not overshoot. So I would be surprised if it just flung up to 200W at it regardless of how close it was getting to temp.

My theory on the overshoot is that either:
a) It's maintaining at 600 just fine, and it's just that the glow is more than they're expecting so it seems more than is needed when it's actually accurate
b) if it is actually overshooting, then there must be a fair bit of SR as Tony said.

Certainly it's a good idea to set it a little lower than theoretically required, as the cleaning differences from coming a bit under 600°C will be minimal, whereas the effect on the wire from going a bit over could be more major.

I'll try and test it, but might not be able to easily do so at 600°C as my good probes aren't rated for that and the probes I have that are are sucky, very low response time ones.

But I will certainly be able to validate the (lack of) overshoot at lower temps with the DNA 200, like I've already seen on the 40 and other mods.

It can happen that I have made something wrong. But I have seen the same slow pulsing (3-4 sec cycle time, Ti, 29awg) on the DNA200 as on the SXK. Of course it can happen only with dry coil and I think it isn't unexpected.
I will test it again to be sure.

 

[TheBloke]

It can happen that I have made something wrong. But I have seen the same slow pulsing (3-4 sec cycle time, Ti, 29awg) on the DNA200 as on the SXK. Of course it can happen only with dry coil and I think it isn't unexpected.
I will test it again to be sure.

OK cool. I haven't actually tested the DNA 200, so I am just assuming it's as good as the 40! Maybe it isn't I will try and do real temp testing of it soon.

 

[TheBloke]

Though even the Apollo Reliant (with latest, updated SXK chip) doesn't overshoot on dry coils, at least in my tests of SS and NiFe70, so it's not common in my experience.

The original SXK did though yes, that was quite all over the place. Up to 15°C over.

 

[druckle]

Yes exactly. So if you imagine using it with a 1.0Ω base resistance coil, the numbers on the Resistance Factor would be the resistance itself at that temperature. For other resistances, multiply as appropriate.



Yes in theory! You might want to set it a bit lower for now, both because of what Tony and Duane are saying, and just until I validate the scale does work like I calculated.



I need to test this on the DNA 200, but I doubt this is true. It is not my experience with actual temperature testing on the DNA 40 on dry coils - which form the majority of my temp testing to date on all mods, as it's so much easier than wet coils with airflow. The DNA 40 never, ever overshoots, and nor do most mods I've tested.

The DNA 200 could be configured with up to 200W pre-heat, which could perhaps make a difference. Then again on the 40, it seems smart about not applying the pre-heat, or not all of it, to make it not overshoot. So I would be surprised if it just flung up to 200W at it regardless of how close it was getting to temp.

Edit: to be clear, the DNA 40 with Ni200 did fluctuate in a range of up to 3°C higher or 3°C lower than the configured temp, but I consider this within the expected, acceptable range. Plus that's Ni200, the least accurate material. I consider an overshoot to be >10°C over the target temp, which I have seen on some mods eg the Joyetech Evic, usually at the start of the pulse and probably associated with unrestricted pre-heat.

My theory on the overshoot is that either:
a) It's maintaining at 600 just fine, and it's just that the glow is more than they're expecting so it seems more than is needed when it's actually accurate
b) if it is actually overshooting, then there must be a fair bit of SR as Tony said.

Certainly it's a good idea to set it a little lower than theoretically required, as the cleaning differences from coming a bit under 600°C will be minimal, whereas the effect on the wire from going a bit over could be more major.

I'll try and test it, but might not be able to easily do so at 600°C as my good probes aren't rated for that and the probes I have that are are sucky, very low response time ones.

But I will certainly be able to validate the (lack of) overshoot at lower temps with the DNA 200, like I've already seen on the 40 and other mods.

I don't know what temperature is really needed to clean a coil. I suppose it depends on what juice has been used and that the deposits may vary a bit. I seemed to see cleaning happening well before the max glow occurred and consequently guessed that I could do the job at a lower temperature.

I never use the 200 watt preheat on the DNA 200 anyway and didn't use it on the temperature limited cleaning. My coils seem to react just fine if the preheat is about twice the set wattage so that's where I tend to leave it most times. I had the preheat set at something like 35 watts(didn't change it from my tank setting) and only 10 watts normal power setting and there was more than enough power available to quickly clean the coil.

Duane

 

[TheBloke]

To be honest I don't think the DNA 200's Preheat settings are needed in most cases, for careful TC users. Or rather, they don't need to be varied.

The theoretical perfect temperature curve is, in my view, is this:

___
|
|

At temperature instantly, then perfectly flat.

Most/all other mods simply throw all their available wattage at the coil, then adjust down when it's at/near temperature.

So the only reason I can think of having the configuration on the DNA 200 is safety - maybe Evolv, or the user, might be worried that a badly setup coil might not regulate correctly, and don't want 200W thrown at a coil which could then self combust.

That's not unreasonable, and I guess the default of 100W pre-heat is sensible. But I can't then see any reason to change it from that setting, I'd just leave it at 100W always - or perhaps increase it to, say, 150W, and then leave it there.

My point is, not varying. I can't think of a reason to have different preheats on different profiles. At least, assuming the DNA 200 is as fast and sensitive as the DNA 40 was, and therefore never overshoots. I would be amazed if it wasn't, as they already had it working right on the 40 and that's the very core of their new technology. But stranger things have happened, certainly. And I suppose working right at 40W might not, theoretically, equate to also doing so at 200W. I'd still be surprised though.

Anyway my actual vaping time with the 200 is very limited thus far so perhaps I'm missing something!

 

[balazsk]

OK cool. I haven't actually tested the DNA 200, so I am just assuming it's as good as the 40! Maybe it isn't I will try and do real temp testing of it soon.

I have repeated the test and the result is the same. I can see slow pulsing on SXK (cycle time: 3-4 sec) and faster on the DNA200 (cycle time: ~1sec). Maybe it can't be seen with thicker wire, I use 29ga Ti. But I think this is normal thing, there isn't universal control algorithm what can work independently from the conditions and from the environment. It can happen that the DNA40 doesn't show this behavior with a dry coil but it doesn't mean that it's better when it is used for vaping.

 

[TheBloke]

I have repeated the test and the result is the same. I can see slow pulsing on SXK (cycle time: 3-4 sec) and faster on the DNA200 (cycle time: ~1sec). Maybe it can't be seen with thicker wire, I use 29ga Ti. But I think this is normal thing, there isn't universal control algorithm what can work independently from the conditions and from the environment. It can happen that the DNA40 doesn't show this behavior with a dry coil but it doesn't mean that it's better when it is used for vaping.

Can you explain what test you're doing? Are you measuring the temperature of the coil?

 

[balazsk]

Can you explain what test you're doing? Are you measuring the temperature of the coil?

I wasn't measuring the temperature because I don't have a temperature sensor what is fast enough. I was just watching the coil, it is glowing up periodically.

 

[TheBloke]

I wasn't measuring the temperature because I don't have a temperature sensor what is fast enough. I was just watching the coil, it is glowing up periodically.

OK. I'll try and do the 200 as soon as I can.

I haven't yet tested the 200 and I've never tested regulation as high as 600°C, so perhaps my results are not applicable for either reason.

I'm trying to find some thermocouples that can do 600°C and aren't a solid metal probe, but no luck so far. Best I can find is 400°C, which I'll probably get. The probe ones I've tried are pretty useless as response time is in the minutes.

I do see some 1mm probes, thinner than I've tried, perhaps that might be slightly better.

Edit: correction, I can find bare metal 600°C probes but only from Hong Kong. So I will order one of those but won't get it for a couple of weeks.

 

[f1vefour]

You need ceramic probes.

*edit*
I agree, response time would likely be hindered, unless the ceramic was super thin.

 

[TheBloke]

You need ceramic probes.

Don't exist I think? Not that I'm seeing anyway under thermocouple probes. I am seeing some where the wiring is covered in ceramic beads, apparently for kilns, but not the probe head itself.

In any case, the probe material itself has to be metal - two kinds of metal with specific resistances which when welded together create EMF that corresponds to the temperature. For example my Type K probes are NiCr and NiAl.

So by definition any probe like ceramic would be over the top of the bare metal, and would be an extra barrier to response time.

The only advantage would be it couldn't short, but in practice I've found I don't get shorting problems as long as my coils are slightly spaced - I can touch the end of the probe directly to one of the wraps and it doesn't short. And I have to do that, else I don't measure the max temperature. Even the slightest air gap and I could be reading 10-20°C lower than the coil itself.

I found a bare metal end 600°C probe in the UK. It's really cheap, the sort that sells from China for about £1. Much lower quality than the handmade ones I've been buying in the UK. But I'll give it a go. 10°C of inaccuracy or so is acceptable at 600°C, we just need to know it's not going way over.

 

[TheBloke]

These are the probes I've used so far, using 0.13mm wire and rated up to 250°C with great response time:



It's the exposed bare metal weld at the tip that's important for response time:

 

[f1vefour]

What about this: Oakton High-Temperature Flexible Wire Thermocouple Probe, Type K, WD-93631-20

3 second response time is awesome, as is the price for such range and speed.

 

[TheBloke]

What about this: Oakton High-Temperature Flexible Wire Thermocouple Probe, Type K, WD-93631-20

Yeah I see a lot like that - it's the stainless steel probe that's the issue. That one is 1.6mm so thinner than the probe-tips I have right now, which are 3mm and completely useless. So it probably is a bit better. But I would still think it's going to be much slower than an exposed tip like I showed above.

I see some 1mm probes on eBay, I might give one a go just to see. Though it does raise the question of how to touch it to the coil. It would be nice if I could just touch the whole probe across the coil, but I'm worried that will almost certainly short. So if I need to touch a single wrap, it might be hard to position the probe -I'll need to come in from the side, pushing it against one wrap.

Probably would work, but lowers response time even more because most of the probe is outside the coil.

What I do with my bare metal probes is run the wire of the probe through the coil twice, then have the end touching one of the wraps, ideally from inside the coil. So the last ~ 10cm of the wire is all inside the coil, which I think helps the response time. Only the metal tip itself actually measures the temperature, but the more temperature that goes into the wire near that tip, the more that will build up the temp in the tip itself. At least that's my theory.

So I think the loose wire/bare metal probes have a lot of advantages. But I will try a thin probe just to see.

Oh hang on, I just noticed that one does list a response time of 3s. Hmm, that doesn't sound too bad. My bare metals are quoted as 1s. OK it's definitely worth a go, thanks!

I don't think I'll get that one though, $36 is a bit much to take a chance on But I'll try a reasonable quality 1mm probe and hope it's similar in response time. Certainly for the 600°C measuring, slow response is not so critical as we just want a maximum.

 

[dwcraig1]

Nothing much to say here 'cept I made a coil that I'm vaping with from my cheap FT Ti, really can't see much if any difference with it and what I was using other than it's (was) a bit dirty. using value of .0040 now. It smells (did)just like a dirty new clone atty.