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

[aldenf]

Thanks, guys. I'm really trying to simplify the science for those without interest or aptitude.

I spent some time in Steam Engine with what seems to be a common coil build across multiple wire types (keeping KA1 for reference).

26awg (0.405mm), 8 wrap @ 2.5mm∅, 0.5mm spacing - this geometry provides a heat flux of 8.88/watt, regardless of wire type. As Heat Flux is geometry dependent, we generally should be building our coils for geometry.

Wire Type / Ω / Heat Capacity / TC Precision
Sorry. Forum software doesn't retain formatting...

KA1 / 0.996 / 37.24 / 2
SS 316 / 0.530 / 45.61 / 466
SS 430 / 0.412 / 40.59 / 569
Ti - Gr1 / 0.323 / 26.42 / 1182
Ni200 / 0.066 / 46.22 / 396
NiFe30 (Resistherm) / 0.227 / 42.07 / 725
Nifethal 52 (NiFe 48) / 0.254 / 46.75 / 1026

On paper, Grade 1 Titanium seems to be the winner across all metrics, with resistance just about median/average. It's handling, oxidation and corrosion characteristics may mitigate the above numbers for many vapers, however. The other wires are simply trading off resistance for higher TC precision. This may be important in multi-coil builds, etc.

As TheBloke pointed out much earlier in the thread, Ni200 seems to be our worst choice for TC vaping across the board. It still may be a good choice for single-coil builds with straight 30awg wire, from purely a TC perspective.

Given identical geometries, all builds should show the same relationships as the above chart, in regards to different wire type. It seems up to us to choose the appropriate wire for our targeted geometries.

How the Heat Capacity effects ramp time is unknown to me. I understand that the lower the Heat Capacity, the lower the ramp-up/cool down. However, does twice the Heat Capacity simply double the ramp-up or is the scale logarithmic, etc?

Am I missing anything here?

 

[cigatron]

How the Heat Capacity effects ramp time is unknown to me. I understand that the lower the Heat Capacity, the lower the ramp-up/cool down. However, does twice the Heat Capacity simply double the ramp-up or is the scale logarithmic, etc?

Am I missing anything here?

Good question. I can't answer that from a purely materials science/ physics prespective, don't have the math skeels.
What we do know is that heat capacity and mass are proportionally related and heat flux is inversely portional to both.
Put any build into SE and note the HC, Mass and HF values. Then increase the target res 2x. The HC and Mass double while the HF halves.
I'm assuming then that the ramp time would double at the same wattage but here's the thing, most of us would just turn the wattage up to speed ramp time and heat flux sooooo.....

With high powered regulated mods these days I design for coil geometry using only 28g or thicker wire (except for claptons and twisted) and heat flux 290 & 320.

 

[druckle]

Thanks, guys. I'm really trying to simplify the science for those without interest or aptitude.

I spent some time in Steam Engine with what seems to be a common coil build across multiple wire types (keeping KA1 for reference).

26awg (0.405mm), 8 wrap @ 2.5mm∅, 0.5mm spacing - this geometry provides a heat flux of 8.88/watt, regardless of wire type. As Heat Flux is geometry dependent, we generally should be building our coils for geometry.

Wire Type / Ω / Heat Capacity / TC Precision
Sorry. Forum software doesn't retain formatting...

KA1 / 0.996 / 37.24 / 2
SS 316 / 0.530 / 45.61 / 466
SS 430 / 0.412 / 40.59 / 569
Ti - Gr1 / 0.323 / 26.42 / 1182
Ni200 / 0.066 / 46.22 / 396
NiFe30 (Resistherm) / 0.227 / 42.07 / 725
Nifethal 52 (NiFe 48) / 0.254 / 46.75 / 1026

On paper, Grade 1 Titanium seems to be the winner across all metrics, with resistance just about median/average. It's handling, oxidation and corrosion characteristics may mitigate the above numbers for many vapers, however. The other wires are simply trading off resistance for higher TC precision. This may be important in multi-coil builds, etc.

As TheBloke pointed out much earlier in the thread, Ni200 seems to be our worst choice for TC vaping across the board. It still may be a good choice for single-coil builds with straight 30awg wire, from purely a TC perspective.

Given identical geometries, all builds should show the same relationships as the above chart, in regards to different wire type. It seems up to us to choose the appropriate wire for our targeted geometries.

How the Heat Capacity effects ramp time is unknown to me. I understand that the lower the Heat Capacity, the lower the ramp-up/cool down. However, does twice the Heat Capacity simply double the ramp-up or is the scale logarithmic, etc?

Am I missing anything here?

 

[aldenf]

Good question. I can't answer that from a purely materials science/ physics prespective, don't have the math skeels.
What we do know is that heat capacity and mass are proportionally related and heat flux is inversely portional to both.
Put any build into SE and note the HC, Mass and HF values. Then increase the target res 2x. The HC and Mass double while the HF halves.
I'm assuming then that the ramp time would double at the same wattage but here's the thing, most of us would just turn the wattage up to speed ramp time and heat flux sooooo.....

With high powered regulated mods these days I design for coil geometry using only 28g or thicker wire (except for claptons and twisted) and heat flux 290 & 320.

Thanks, Cigatron!

Indeed, HF seems to be dependent on surface area. HC seems to be dependent on mass, given the same wire. This makes complete sense from a physics perspective.

 

[dwcraig1]

My Nife30 (really 70) is a bit slow arriving but I expect to have it within about 4 more days.
I'm thinking about trying to make a dual core clapton with some 29 gauge Resistherm and 34 gauge Kanthal, that ought to be quite a challange for me.
Edit: it just finally passed through NY ICS

 

[trincisor]

So I have the TCR from steamengine fit NiFe52 (well is NiFe48 from ZiViPf)

And if I lock the resistance at say .08 and go to run it at 50w and 420 degrees, I get an almost instant temp warning. Even running it at 550 got me the instant warning.

But if I heat the coil a little and set it to .09 it works pretty damn well.

Anyone got any solutions?

Sent from my XT1060 using Tapatalk

Are you using a evic vtc mini? Think it could be your mod?

Sent from my D6503 using Tapatalk

 

[Eric Auer]

SS430 again, On a Kraken Brass clone:

Eric

 

[cigatron]

SS430 again, On a Kraken Brass clone:

Eric

Nice. Question, does your VTC Mini charge the batt to the full 4.2v? My Cuboid only charges the batts to 4.0v.

 

[Eric Auer]

Nice. Question, does your VTC Mini charge the batt to the full 4.2v? My Cuboid only charges the batts to 4.0v.

No clue, have not tried to charge in the mini, I have a external charger for my 18650's and 26650's.

Eric

 

[aldenf]

Nice. Question, does your VTC Mini charge the batt to the full 4.2v? My Cuboid only charges the batts to 4.0v.

When I first got my VTC Mini, I tried charging a battery (HE2) in the mod twice. Both times it charged to 4.2V. I generally charge my batts outside the mod though. I'll sometimes use the mod to charge when I'm traveling.

 

[cigatron]

When I first got my VTC Mini, I tried charging a battery (HE2) in the mod twice. Both times it charged to 4.2V. I generally charge my batts outside the mod though. I'll sometimes use the mod to charge when I'm traveling.

Yeah this. I have two 4bay chargers but it's nice to know the usb will charge the mod just in case. Looking through my cuboid manual just now it says that they don't recommend charging through the usb port....hmmmm

 

[JimScotty0]

Yeah this. I have two 4bay chargers but it's nice to know the usb will charge the mod just in case. Looking through my cuboid manual just now it says that they don't recommend charging through the usb port....hmmmm

Sounds like they don't have their battery balancing act together then.

 

[cigatron]

Sounds like they don't have their battery balancing act together then.

Not sure if it's a series or parallel battery config. The display has a battery level monitor for each of the two 18650's so I'm assuming it's series. If so, it is charging balanced albeit only to 4.0v

 

[KenD]

Nice. Question, does your VTC Mini charge the batt to the full 4.2v? My Cuboid only charges the batts to 4.0v.

Did you check the voltage on the mod or on a multimeter?

Sent from my M7_PLUS using Tapatalk

 

[KenD]

Sounds like they don't have their battery balancing act together then.

I think it's more about not breaking the usb port. With updateable mods that's my main reason for not charging through the usb.

Sent from my M7_PLUS using Tapatalk

 

[aldenf]

Not sure if it's a series or parallel battery config. The display has a battery level monitor for each of the two 18650's so I'm assuming it's series. If so, it is charging balanced albeit only to 4.0v

I believe it's a series mod. The battery door closes pos to neg. That should mean series, no?

 

[cigatron]

I believe it's a series mod. The battery door closes pos to neg. That should mean series, no?

It should, thanks.

 

[dwcraig1]

My resistherm claptons was pretty easy, ordered another 100' of 34 gauge Kanthal as it's going quickly.
I didn't have time to make any coils with it yet though.
Edit: Looks like I'm not using as much 34 gauge as I thought, well I won't be running low on it anytime soon I guess.

 

[Boxster]

Check out 430ss at unkamen supplies if you're set on SS. Tcr and res is close to Ti and you can dryburn it at cherry red temps. Wouldn't go to yellow temps though because it can get brittle. Good luck.

Thanks cigatron, I appreciate the response. I went ahead and ordered both the 430ss and TI.

 

[cigatron]

Thanks cigatron, I appreciate the response. I went ahead and ordered both the 430ss and TI.

I think you'll like both. For obtaining the best coil symmetry I lightly torch both wire types to anneal (soften) them to take out some of the springyness. They pretty much coil up just like kanthal after annealing.
I'm still pretty much a 24g Ti guy but the 25g Nife52 that @Landman pifd to me seems to work quite well too. It's certainly easier to coil with ie no annealling required and is dryburnable too. Jury's still out on NiFe52 durability but so far it's holding up well in my Crius RTA.