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

[Shawn Hoefer]

FT carries UD branded wires, and I believe they are trustworthy, altho I have not tested or seen tests...

 

[druckle]

Thank you Duane!
I experienced it with SS304. I am not sure that this the real root cause but I don't have better idea.
I should order some silicone oil and do measurements with different wires.

@balazsk

304 SS is generally considered not to be heat treatable and I'm sure there would be no significant solid state reactions that would affect TCR, however; it is generally recognized that there is often a difference in TCR measured on heating a sample compared to TCR measured when cooling the sample. Part of this is apparently due to stress relaxation/annealing. The degree of work hardening in each coil is going to be unique so I don't think it's possible A priori to know whether the TCR for a given coil will change from dry burning.

I will say if it is possible to see a significan't change it's most likely to be seen in a material with a very low TCR such as stainless steel.

Duane

 

[Mactavish]

I couldn't bless or disapprove any material based on source other than to say that FT is in the business of buying cheap and selling cheap. I seriously doubt if they have a materials laboratory or care to have someone else analyze the material they sell. China has the capability and does make some of the best materials in the world. They also make some absolutely horrendous materials. In that way they are no different than just about any other country.

The price of wire for vaping is minuscule in the long run if the life of the material is decent so I try to purchase that (and any material I use) from sources I know to be reliable and do not rely on technobabble to sell their product. I probably could save a dollar or two but then who knows?

Duane

Duane, I'd like to try building with Titanium, can you recommend a USA vendor or source?
TKS!

 

[druckle]

Duane, I'd like to try building with Titanium, can you recommend a USA vendor or source?
TKS!

I've used both Unkamaen available in a range of useful gauges
Pure Titanium Wire 100% Guarantee Specific by UnkamenSupplies

and Rio Grande (unfortunately only available in a usable 24 gauge.
Titanium Round Wire, 10-ft. Coil, 16-Ga., Soft

Rio Grande has thicker wire but that becomes problematic. The Rio Grande 24 gauge is fully annealed and very easy to work with. The Unkamen wire is about half annealed but still quite workable.

Both of these sources seem to have good product and I've used both quite successfully.

Duane

 

[BigEgo]

Duane, I'd like to try building with Titanium, can you recommend a USA vendor or source?
TKS!

There's also a GalliumSource. According to comments on Amazon, his wire is certified Grade 1 and he can provide COA's upon request. GalliumSource only lists 24 guage Ti on the site, but I am pretty certain you can contact them directly to order other gauges. I have no personal experience with this wire.

They also carry various other metals that might be of interest, like Tungsten. However, I can warn to stay far away from Thallium!

 

[cigatron]

FT carries UD branded wires, and I believe they are trustworthy, altho I have not tested or seen tests...

Amazon carries Lightening Vapes brand kanthal; not reliable at all. Res was off 9% low from 29ga spec even though it was diametrically correct. I wound my standard twisted 29's with it but could never get the res to come up with repeated dryfires. The coils fired perfect so I was confident the alumina had properly developed but the res was still low.

I unspooled and lighty tensioned 10 ft. of wire, measured the res with my HP .xxx1/2 meter,subtracted the test lead res and divided by 10. Sure enough, it was off. I've used Temco Industrial ever since; spot on every time.

Same with unkamen for Ti-G1; spot on res.

 

[druckle]

Amazon carries Lightening Vapes brand kanthal; not reliable at all. Res was off 9% low from 29ga spec even though it was diametrically correct. I wound my standard twisted 29's with it but could never get the res to come up with repeated dryfires. The coils fired perfect so I was confident the alumina had properly developed but the res was still low.

I unspooled and lighty tensioned 10 ft. of wire, measured the res with my HP .xxx1/2 meter,subtracted the test lead res and divided by 10. Sure enough, it was off. I've used Temco Industrial ever since; spot on every time.

Same with unkamen for Ti-G1; spot on res.

Well I'm probably going to make a controversial comment but my experience is that Vaping vendors are in general the poorest sources for wire. They generally don't have the staff to understand the materials and are motivated almost entirely by profit potential. Some of them (one in particular) out and out lies about their material .GalliumSource is materials oriented and people like Unkamen and Rio Grande who are jewelry motivated usually are aware of chemistry affects on their customers and seem to do a better job.

Of course folks like Temco who are in the materials business as manufacturers are reliable. Unfortunately their range of offering is limited to what they specialize in.

Duane

 

[BigEgo]

Druckle, what's your opinion of Tantalum? It's TCR is identical to Ti's (.0038). It is inert in the human body and highly resistant to corrosion. I'm not sure, however, how high it's resistance is compared to other metals or how practical it would be for coils.

 

[druckle]

Druckle, what's your opinion of Tantalum? It's TCR is identical to Ti's (.0038). It is inert in the human body and highly resistant to corrosion. I'm not sure, however, how high it's resistance is compared to other metals or how practical it would be for coils.

I haven't looked into tantalum in detail so I don't know if it offers something that would make it superior to titanium. It is often used for heat shields in vacuum furnaces because of it's affinity for oxygen and it's high heat resistance. (Grabbing oxygen out of a vacuum furnace helps protect materials being exposed to heat treatment etc. to be less contaminated.

Tantalum has somewhat the same oxidation characteristics as Titanium and I believe the price is high so if it does have a benefit it would have to be substantial to make it worth while.

Duane

 

[tchavei]

Actually it is possible with the accuracy of our mods.
Specific TCR can be calculated to shift the real temperature for dry burning. I have made it for Ti: if you set the TCR to 0.00725 and the temp to 300°C the coil will be about 600°C.
I am sure that it's not perfect, the TC algorythm has been developed for wet coils, but it is good enough to have a rough limit.

Profile #8 is now "Clean Coil" set to 300C and a TCR of 0.00725

Thank you

Regards
Tony

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

 

[cigatron]

Profile #8 is now "Clean Coil" set to 300C and a TCR of 0.00725

Thank you

Regards
Tony

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

Nice, a tightly controlled temp for optimum dryburning of each particular wire type.

#8 "clean Ti"
#9 "clean NiFe"
#10 "clean mistery wire"

I love it!

When dryburning your Ti at 600c what intensity of redness do you see while in a normally lit room? Also, what wattage is displayed once tp is reached?

 

[Fsx]

Hi, everybody! One simple question. What is negative about titanium wire dry burning? Done it few times and there is no issues. But, I've bought ti wire in joyetech local store in Moscow, Russia. It is not shiny and not springing at all (some kind of "pre-fired" I think), very simple coil building, even easier than with kanthal.
Thanks in advance for ur replies and sry for my English))

 

[cigatron]

Hi, everybody! One simple question. What is negative about titanium wire dry burning? Done it few times and there is no issues. But, I've bought ti wire in joyetech local store in Moscow, Russia. It is not shiny and not springing at all (some kind of "pre-fired" I think), very simple coil building, even easier than with kanthal.
Thanks in advance for ur replies and sry for my English))

@Fsx, welcome to ecf. Two things that generally come to mind concerning Ti:

1. Titanium can ignite if overheated. It cannot be extinguished with water..

2. There are health concerns regarding the formation and possible inhalation of Titanium Dioxides.

I have carefully dryburned my Ti coils at 20w in power mode repeatedly over the last 2 months and with brushing and washing have been able to remove the white powdery dioxides each time.

A couple of days ago I got distracted and slightly overheated one Ti coil. A heavy layer of dioxides formed on the wire surface and would not wash off. Under 20x magnification it was apparent that some spalling of the oxide layer had occurred. That is, small areas of delamination of the oxide layer were visable. The oxide layer had lost adhesion with the base metal. It was flaking off in other words. To be safe I pitched the coil and rewound another..

Not sure about the Ti you purchased from JTech but if its easy to work with its probably pre annealed.

Hope this helps

 

[druckle]

Actually it is possible with the accuracy of our mods.
Specific TCR can be calculated to shift the real temperature for dry burning. I have made it for Ti: if you set the TCR to 0.00725 and the temp to 300°C the coil will be about 600°C.
I am sure that it's not perfect, the TC algorythm has been developed for wet coils, but it is good enough to have a rough limit.

@balazsk

I did your controlled temp dry burn even though my coil was only a couple months old and looked good still. I just got entirely too curious to see the results and had to do it.

Here's the story.

I had a 3mm dia 24 gauge coil Rio Grande Ti wire coil, 0.2 ohms 6 wraps, slightly spaced.

I set the power at 10 watts and pushed the button…heating wasn’t instantaneous but that’s what I wanted so I could be sure I had good control.

First a little smoke…then a glow starting from the center spreading to the outside as with a contact coil.

I was in pretty bright light and my guess is the temp is higher than 600C if I measured it but the mod did reach temp limit…

I pulsed it that way 3 or 4 times for maybe a second per pulse

Result

A totally clean coil. Maybe slightly blue…(I started with a shiny clean wire).

Cleaning took only seconds.

My guess is that I could reduce the temp a little in the future…but then I’m not sure I need to.


I generally don't bother to dry burn titanium because I haven't felt I needed to .
Given how quick and controlled your procedure is @balazsk this may become the way I clean coils every time in the future.

Anyone could create a condition for a specific wire and make the whole cleaning thing fool proof.

My judgment

This is a fantastic process with the potential to make coil cleaning 100% foolproof and safe for virtually any wire if parameters are adjusted for the specific material.

Thanks so much for posting your method.

I love it

Duane

 

[balazsk]

@balazsk

I did your controlled temp dry burn even though my coil was only a couple months old and looked good still. I just got entirely too curious to see the results and had to do it.

Here's the story.

I had a 3mm dia 24 gauge coil Rio Grande Ti wire coil, 0.2 ohms 6 wraps, slightly spaced.

I set the power at 10 watts and pushed the button…heating wasn’t instantaneous but that’s what I wanted so I could be sure I had good control.

First a little smoke…then a glow starting from the center spreading to the outside as with a contact coil.

I was in pretty bright light and my guess is the temp is higher than 600C if I measured it but the mod did reach temp limit…

I pulsed it that way 3 or 4 times for maybe a second per pulse

Result

A totally clean coil. Maybe slightly blue…(I started with a shiny clean wire).

Cleaning took only seconds.

My guess is that I could reduce the temp a little in the future…but then I’m not sure I need to.


I generally don't bother to dry burn titanium because I haven't felt I needed to .
Given how quick and controlled your procedure is @balazsk this may become the way I clean coils every time in the future.

Anyone could create a condition for a specific wire and make the whole cleaning thing fool proof.

My judgment

This is a fantastic process with the potential to make coil cleaning 100% foolproof and safe for virtually any wire if parameters are adjusted for the specific material.

Thanks so much for posting your method.

I love it

Duane

I am happy that it worked so good!
I think the control algorithm has been tuned for wet coils and it isn't fast enough to control a dry coil properly. Maybe we could measure the real temperature and set the mod accordingly but I am sure that it won't be the same with different kind of mods.
Anyway it seems that it's good enough to keep the coil in the safe temperature range.
Thank you for the test @druckle !

 

[cigatron]

@balazsk

I did your controlled temp dry burn even though my coil was only a couple months old and looked good still. I just got entirely too curious to see the results and had to do it.

Here's the story.

I had a 3mm dia 24 gauge coil Rio Grande Ti wire coil, 0.2 ohms 6 wraps, slightly spaced.

I set the power at 10 watts and pushed the button…heating wasn’t instantaneous but that’s what I wanted so I could be sure I had good control.

First a little smoke…then a glow starting from the center spreading to the outside as with a contact coil.

I was in pretty bright light and my guess is the temp is higher than 600C if I measured it but the mod did reach temp limit…

I pulsed it that way 3 or 4 times for maybe a second per pulse

Result

A totally clean coil. Maybe slightly blue…(I started with a shiny clean wire).

Cleaning took only seconds.

My guess is that I could reduce the temp a little in the future…but then I’m not sure I need to.


I generally don't bother to dry burn titanium because I haven't felt I needed to .
Given how quick and controlled your procedure is @balazsk this may become the way I clean coils every time in the future.

Anyone could create a condition for a specific wire and make the whole cleaning thing fool proof.

My judgment

This is a fantastic process with the potential to make coil cleaning 100% foolproof and safe for virtually any wire if parameters are adjusted for the specific material.

Thanks so much for posting your method.

I love it

Duane

So maybe I should step down in dryburn wattage from 20w to 10w? I'll try that next time but when I started dryburning Ti 2 months ago that's where I started, 10w. It seemed to take too long to begin the smouldering of the gunk. I'm a bit impatient like that.

Here's an interesting thing, when dryburning my coils always start glowing from the outside first until the gunk smoulders off. I vape NETs, they gunk coils up very quickly, 15-20 mil of vaping. The gunk is much heavier in the center of the coil than on the ends, most times bridging across the spaced turns, so the first signs of glowing red always happens at or near the end turns. I suppose the heavy gunk is adding thermal mass to the center of the coil slowing heating there. Once the end turns just begin to turn red I release the fire button and blow on the coil. With the increased oxygen the gunk will then smoulder from the end turns to the center without any power applied. I brush and rinse the ash off and from that point forward the coil fires center out.

It's a different process than yours but one that I believe keeps the wire temp at an absolute minimum while converting the gunk to ash. A process you may feel necessary if you ever gunk a coil to the extent that NETs do.

 

[druckle]

So maybe I should step down in dryburn wattage from 20w to 10w? I'll try that next time but when I started dryburning Ti 2 months ago that's where I started, 10w. It seemed to take too long to begin the smouldering of the gunk. I'm a bit impatient like that.

Here's an interesting thing, when dryburning my coils always start glowing from the outside first until the gunk smoulders off. I vape NETs, they gunk coils up very quickly, 15-20 mil of vaping. The gunk is much heavier in the center of the coil than on the ends, most times bridging across the spaced turns, so the first signs of glowing red always happens at or near the end turns. I suppose the heavy gunk is adding thermal mass to the center of the coil slowing heating there. Once the end turns just begin to turn red I release the fire button and blow on the coil. With the increased oxygen the gunk will then smoulder from the end turns to the center without any power applied. I brush and rinse the ash off and from that point forward the coil fires center out.

It's a different process than yours but one that I believe keeps the wire temp at an absolute minimum while converting the gunk to ash. A process you may feel necessary if you ever gunk a coil to the extent that NETs do.

If your coils are glowing at the end first It could also be the low thermal conductivity of the "gunk" compared to the metallic coil? In effect the thermal insulation of the gunk could be keeping the outside center cool while the metal underneath is hotter? In the end as the gunk is oxidized and removed you may be noticing the coil begin to glow in the center because the deposit is becoming thinner.

Duane

 

[cigatron]

If your coils are glowing at the end first It could also be the low thermal conductivity of the "gunk" compared to the metallic coil? In effect the thermal insulation of the gunk could be keeping the outside center cool while the metal underneath is hotter? In the end as the gunk is oxidized and removed you may be noticing the coil begin to glow in the center because the deposit is becoming thinner.

Duane

Makes perfect sense to me. The gunk serving as a thermal insulator and thereby conceiling the glowing wire beneath. But if that's the case and it's causing the wire surface to be hotter in the center during the initial dryburn pulse wouldn't I see heavier pitting on the wire surface there than the end turns. Over time, with numerous dryburns, the pitting seems to be unform throughout. I'm not formally educated in material science as you are, so I do make a lot of assumptions based on observation. I'm assuming here that the pitting is caused by the sloughing off of dioxides which did not adhere well to the base metal after formation on the wire surface due to excessive heat?

Do your coils look similar to mine after dozens of rewickings?

 

[druckle]

Makes perfect sense to me. The gunk serving as a thermal insulator and thereby conceiling the glowing wire beneath. But if that's the case and it's causing the wire surface to be hotter in the center during the initial dryburn pulse wouldn't I see heavier pitting on the wire surface there than the end turns. Over time, with numerous dryburns, the pitting seems to be unform throughout. I'm not formally educated in material science as you are, so I do make a lot of assumptions based on observation. I'm assuming here that the pitting is caused by the sloughing off of dioxides which did not adhere well to the base metal after formation on the wire surface due to excessive heat?

View attachment 487934



Do your coils look similar to mine after dozens of rewickings?

I don't know what is happening for sure but I would expect lower oxygen concentration under a thick layer of gunk compared to the ambient air so if in fact the center of the coil is hotter with the gunk layer on it there might be less actual oxidation occurring while the layer is thick thus more or less evening out the total oxidation over the length of the wire. I'm guessing here, but I have noticed the same thing with thick deposits on the coil and have scratched a local area to remove some of the gunk then fired and then I see a bright patch where I've scratched off the deposit. I'm sure things could be different for each specific setup but I think that could be a possibility for you too.

In the last few months I've been dry burning titanium a lot less because I haven't needed to with the e liquids I'm using so my coils stay pretty much looking as new.

Duane

 

[Croak]

Next time you change coils, you might want to loosen that 510 screw and adjust your positive post there mate, it's more than a wee bit cockeyed.

Dry burn cleaning isn't really a consideration with me, since I generally replace my coils with the wicks these days, and that's usually three or four times a week per atty, if not daily on some.