Tensioned Micro Coils. The next step.

[Boden]

This has to be the most complex thread on how to make an extension spring using Kanthal in the history of the interwebs.

 

[herb]

This has to be the most complex thread on how to make an extension spring using Kanthal in the history of the interwebs.

Tell me about it , Jesus man lol. Luckily i'm completely satisfied with the performance of the basic (normal tensioned) coil types.

 

[MacTechVpr]

Tell me about it , Jesus man lol. Luckily i'm completely satisfied with the performance of the basic (normal tensioned) coil types.

This has to be the most complex thread on how to make an extension spring using Kanthal in the history of the interwebs.

The subject of this thread is quite simple really…how to use strain (elongation) to stabilize a contact coil which is unpredictably overheating and oxidize it to the point of a stable complete circuit. The result is typically upwards of 25% increase in production efficiency, resistance stability and predictability. The method I introduced for applying strain by hand tension winding makes it possible for anyone to accomplish this in seconds.

Now some of the winds and methods discussed on this advanced thread are exactly as you say. Extensions and adaptations beyond the basic methods I discuss for winding and building elsewhere. Take what works for you.

There is no normal tensioned coil. Tensioned winding balances the internal stress of wire so as to stabilize its resistance which is thrown off in a contact coil. There is no normal such coil. Wires aren't supposed to touch or cross. Internal wire stress or the external force applied to a wire (strain) is used in every kind of wind. You're using it if you're vaping it all. The methods I've introduced on ECF promote consistent reproduction by equalizing and balancing that strain.

I recommend enthusiastically that new vapers learn to tension wind so that they can get to a reliable vape with results like many of us have been enjoying for some time. Not hit-or-miss but every time. And many of the principles I discuss can be applied to most every wind type. Most importantly oxidation of Kanthal contact coils, the objective of tension winding. Passed this on in a personal tutorial with two new vapers in minutes just this very afternoon. The complementary build mechanics a bit longer but produced successful symmetrical oxidized .4Ω pair on first attempt.

Interestingly I queried them about their opinion of whether this approach was complex or difficult to accomplish. Actually highlighted some of the posts made on this forum. What do you think their reply was?

Hope you try it and choose not to dismiss what you haven't seen. The difference once accomplished simply and correctly will add a lot of control to your vape and a great deal of satisfaction.

Good luck fellas.

 

[Boden]

Mac,
You should look up "how to make an expansion spring" it is what you are doing here. In making an expansion spring the higher the initial tension the stronger the spring.

I do use a coil gizmo to make my coils, have for years. I use it because it is easy to make consistent contact spring coils on.

Have I ever noticed a difference between a spring coil and a contact coil wrapped by hand around a screwdriver? One, they are more sturdy.

I can see how this would be valuable to someone who re wicks often as the coil spring is less likely to deform as they remove and replace the wick.

One other thing. When you apply tension to the wire you are not relieving internal tension, you are work hardening the metal so that it keeps its shape. Once you heat the coil to glowing that relaxes the christaline structure somewhat while at the same time thickening the FeCrAl oxide layer.

Boden

 

[herb]

No need to defend your methods Mac , just someones opinion . I have no issues with my vape at all , it's always been very consistent to me and i am very satisfied even if it could be improved . Not criticizing your efforts so keep up the good work.

Nobody will always agree 100% , you know that , i just stumbled onto your post , i wasn't looking for it because i was having any issues.

 

[MacTechVpr]

Mac,
You should look up "how to make an expansion spring" it is what you are doing here. In making an expansion spring the higher the initial tension the stronger the spring.

I do use a coil gizmo to make my coils, have for years. I use it because it is easy to make consistent contact spring coils on.

Have I ever noticed a difference between a spring coil and a contact coil wrapped by hand around a screwdriver? One, they are more sturdy.

I can see how this would be valuable to someone who re wicks often as the coil spring is less likely to deform as they remove and replace the wick.

One other thing. When you apply tension to the wire you are not relieving internal tension, you are work hardening the metal so that it keeps its shape. Once you heat the coil to glowing that relaxes the christaline structure somewhat while at the same time thickening the FeCrAl oxide layer.

Boden

Thanks for your comeback B.

Yes, strain adds rigidity as effectively as torching. A very modest amount can get wires to closest turn-to-turn contact. In this context there's no release of internal stress, there's a substantial addition of it. Just more than necessary for contact seems to reduce the time and amount of power need to initiate alumina formation. And deposition is possible with lower power. Although strain reduces elasticity (work hardening), high power (heat) pulsing can negate it, ex. too much you warp. Not what I encourage. But the combo of strain and low power pulse appear to result in a favorable realignment and balancing of the stress of the wire in assumption of its functional form (a reordering of the lattice). Assuming the wire is not then deformed by higher energy levels in installation such winds runs cooler (higher rate of phase transition) evidencing an optimized electron flow. So you see less deformation or warping unless substantially higher energies are used (during vape or dry burn) than used to create the wind. Modest use of balancing strain can aid in producing very stable winds. That's my proposition.

Best of all it's easy to do for a beginner!

Good luck and vape on.

 

[Boden]

I would like to help and think you might be on to something but for the life of me I can't suss it out. I'll take this one bit at a time.

Yes, strain adds rigidity as effectively as torching.

Torching removes some rigidity by heating the metal to a pliable state. In this pliable state you can move the metal into position more easily until it cools. I'm not sure how this could add rigidity.

A very modest amount can get wires to closest turn-to-turn contact. In this context there's no release of internal stress, there's a substantial addition of it.

I'm assuming you are talking about tension. True

Just more than necessary for contact seems to reduce the time and amount of power need to initiate alumina formation. And deposition is possible with lower power.

Close proximity of coils will aid in mutual heating thus increase the oxide formation between the wraps. Assuming that the "raking" technique is used while heating.

You keep calling it "Alumina", it is a more complex composition than just Al2O3. Referring to it as "Oxide layer" would be more accurate.

Although strain reduces elasticity (work hardening), high power (heat) pulsing can negate it, ex. too much you warp.

The amount it will "Negate it" depends on heat level and time left at an elevated temperature. True

Not what I encourage. But the combo of strain and low power pulse appear to result in a favorable realignment and balancing of the stress of the wire in assumption of its functional form (a reordering of the lattice).

Strangely worded but okay.

Assuming the wire is not then deformed by higher energy levels in installation such winds runs cooler (higher rate of phase transition) evidencing an optimized electron flow.

You lost me at "such winds run(s) cooler" and "evidencing an optimized electron flow".

So you see less deformation or warping unless substantially higher energies are used (during vape or dry burn) than used to create the wind.

Back on point

Modest use of balancing strain can aid in producing very stable winds. That's my proposition.

Makes sense


If I am wrong about my understanding of what you are saying please let me know. I think you are trying to express a simple idea but are doing it in a verbose manner. Simplifying it might be better for beginners.

 

[MacTechVpr]

Get back to you on above. One point I'd like to clarify, add to. And certainly could use the support on this and others to help folks understand the application and value of alumina oxidation (yes, have read on deposition variations). And I appreciate clarification when needed and useful, thanks. Yes I sometimes use some wordy phrasing instead of merely oxidation or AlO3. Often to avoid technical terms and lengthy explanation, e.g. adhesion, short. The audience often makes this a quandary. I'm not an engineer or metallurgist myself but have had the privilege of working with a great many from around the world. I think we seem to agree on statements re metallic properties except for one of your above. I haven't posted an overview of all of my findings here on ECF. In part this affects my explanations at times.

Thanks for your genuine interest Boden. I really don't care about peep's winding choices. I'm a libertarian by nature. Post to encourage rebuilding. My interest is expanding the understanding of stress, always present, and how strain may be used to improve wire/wind performance and build symmetry or stability. I've done quite a bit of research on this subject as well as the human ergonomics of rebuilding with the help of a great many interns and volunteers over two years.

If you didn't catch it recently, check out the confirmations on Kanthal offered by several qualified posters on The end of microcoils? Responses mostly to Dr. Farsalinos assertions that we shouldn't torch (dry burn) at all. In context I believe the thread affirms the substantial utility, practicality and safety of Kanthal (when oxidized) by comparison with alternatives. A good discussion.

Please also see Micro Coils to increase Vapor, flavor & TH | Page 496 (Post 9902), a validation by Bill's Magic Vapor at my introduction Spring of '14 of strain tension winding on super_X_drifter's original microcoil thread, Micro Coils to increase Vapor, flavor & TH.

Take care and good luck. Here anytime if you want to chat.



p.s. Everyone should believe in something; I believe I’ll go fishing. –Henry David Thoreau — We totally agree.

 

[Alien Traveler]

You keep calling it "Alumina", it is a more complex composition than just Al2O3. Referring to it as "Oxide layer" would be more accurate.

But it is alumina.

 

[Boden]

But it is alumina.

Unless you are keeping the coil at 900*C for ~72 hours Fe and Cr are present in the outer layers.

http://du.se/PageFiles/8550/Abstract Josefin E.pdf

Oxidation of FeCrAl alloy: influence of temperature and atmosphere on scale growth rate and mechanism

 

[Boden]

Page 12 under Operating life

http://www2.kanthal.com/sandvik/097...1-A-2-3 appliance handbook US.pdf?OpenElement

"Consists mainly of alumina (Al2O3)"

 

[Alien Traveler]

Unless you are keeping the coil at 900*C for ~72 hours Fe and Cr are present in the outer layers.

http://du.se/PageFiles/8550/Abstract Josefin E.pdf

I will not discuss this abstract since it is dealing not with kanthal but with alloys with low Al content.

Oxidation of FeCrAl alloy: influence of temperature and atmosphere on scale growth rate and mechanism

And this is an example of poorly made paper. If something like this would come to me for review I will kill it (happened so that I know metallurgy and use methods employed in the paper quite often). Authors do not know about spacial resolution of a method they used, so they "found" a lot of Fe in a wrong place.

Can there be something besides Al and O in alumina? Of course. But it is still alumina (on kanthal).
You can take a look at my spectra (same method that was used in discussed paper) here:
Coil under electron microscope | E-Cigarette Forum
It shows a tiny amount of Fe and Cr (after dry burn) but crystallographic data shows it is just alumina:
Oxidation behaviour of Kanthal A1 and Kanthal AF at 1173 K: effect of yttrium alloying addition

 

[Boden]

Okay, for the sake of brevity I'll accept referring to the oxide layer as Al2O3

 

[MacTechVpr]

Welcome AT, Boden thank you both for your thoughts and contributions. Not an ME, EE or materials spec but a professional tech buyer by trade. My goal here rather straightforward…how to make the best out of the thermally optimal geometry of a microcoil. Anything that may help users better understand how to get there, yours truly included, heartily welcomed.

Best of luck to you both.

 

[MacTechVpr]

Surprised this is still live and a good deal if you can get it Kangertech Subox with Kanger Subtank Mini Starter Kit (-10% with coupon "SUBOXDEAL") with free shipping.

Density tensioned micro winds for the OCC and RBA available here…FREE.

Good luck all!



[Lifted from the thread Protank MicroCoil Discussion!! | Page 151 | (Post 3015)

 

[Boden]

. My goal here rather straightforward…how to make the best out of the thermally optimal geometry of a microcoil.

When you say "microcoil" do you mean 'contact coil' or '1.5-2mm coil' ? I've seen people confuse those terms.

Macro = >3mm
Standard = 2-3mm
Micro = 1.5-2mm
Nano = <1.5mm

Optimal would depend on how you want to use the coil. For short high power puffs a coil that is wider than its OD seems to work well. For longer medium temp draws having the width around OD works well. For long flavor low temp draws having the width narrower than the OD works very well. It's all about having the right amount of e-liquid at the right place at the right time.

 

[MacTechVpr]

When you say "microcoil" do you mean 'contact coil' or '1.5-2mm coil' ? I've seen people confuse those terms.

Macro = >3mm
Standard = 2-3mm
Micro = 1.5-2mm
Nano = <1.5mm

Optimal would depend on how you want to use the coil. For short high power puffs a coil that is wider than its OD seems to work well. For longer medium temp draws having the width around OD works well. For long flavor low temp draws having the width narrower than the OD works very well. It's all about having the right amount of e-liquid at the right place at the right time.

Sad state of affairs I think. We have folks even calling Clapton's microcoils.

Back on Feb 1, 2014 I predicted that using the nomenclature "microcoil" without a definition or expression of its function and application would be problematical. I made the case with the blog entry below (the term adhesion I use frequently on ECF and generically, not as a scientific expression, but to refer to closest proximity).

Etymology of the word/s Micro Coil (microcoil) for vaping…

On this thread and elsewhere I've attempted to at least define or explain the function and purpose of a tensioned microcoil (a complete circuit). Many of these I entitled What is a tensioned microcoil? or variation. Unfortunately we've done away with Titles.

Appeal to those who have a technical or scientific classical background to help firm up the definition and criteria. I've done my best to do so. Should you wish to participate please contact me directly by personal message. That's to say adding to the knowledge is very much appreciated.

Here I'd like to extend a warm thank you of appreciation to super_X_drifter who conceived, tested and encouraged the use of the geometry of a microcoil for which all of us should be grateful.

Thanks for your interest Boden.

Good luck.

 

[super_X_drifter]

Thank you Mac . What's really ironic is that I have started to run TSC's now. The "T" part is the hard part with the twisted wire. Yep, my ID has bloated to a lofty 2.5mm in a single coil setup like this:

It produces. I believe my experience indicates to me that in a 22mm atty that doesn't allow a coil setup like that because of a centerpost, a dual coil setup of 2.0mm ID is my sweet spot. In a smaller atty, say 18-14 mm a 1.5ish mm ID coil did it but in my latest favorite atty - the stumpy, a 2.5mm ID coil with twisted (yes, me using twisted wire ) outruns duals in fullness, warmth and quantity of vapor because that big fat coil sits directly in line with and about 1/2" from my mouth. Wide open AFC on both sides. It really is an amazing vape - even at 0.8 ohms. I don't see myself going back to duals now that the simplicity of a single coil can provide such a high performance vape

 

[Aal_]

When you say "microcoil" do you mean 'contact coil' or '1.5-2mm coil' ? I've seen people confuse those terms.

Macro = >3mm
Standard = 2-3mm
Micro = 1.5-2mm
Nano = <1.5mm

Optimal would depend on how you want to use the coil. For short high power puffs a coil that is wider than its OD seems to work well. For longer medium temp draws having the width around OD works well. For long flavor low temp draws having the width narrower than the OD works very well. It's all about having the right amount of e-liquid at the right place at the right time.

Boden I like how you think and challenging the tensioned contact coils will just advance our coiling techniques and for that I thank you.

Now regarding your measurements just to be .... about it a micro coil is between 1.4 and 1.65 if I'm not mistaken

Now regarding your classification of what you want and the shape if the coil I agree with you 100%. It used to be a best practice for me to do that but it's nice to see someone doing the same. It gives credibility to the way I think. Depending on the atomizer I do change the diameter and the gauge of the wire.

 

[Boden]

Boden I like how you think and challenging the tensioned contact coils will just advance our coiling techniques and for that I thank you.

Now regarding your measurements just to be .... about it a micro coil is between 1.4 and 1.65 if I'm not mistaken

Now regarding your classification of what you want and the shape if the coil I agree with you 100%. It used to be a best practice for me to do that but it's nice to see someone doing the same. It gives credibility to the way I think. Depending on the atomizer I do change the diameter and the gauge of the wire.

I'm not challenging anything. There are a thousand ways to wrap a coil and they are all right... well, unless you blow something up

Fine... micro coil, larger than nano but smaller than macro. Got it

Long ago in a thread long forgotten we got into the fluid dynamics of wicking materials to a level that was, quite frankly, silly. Out of that study came the simple idea of a wick as a capacitor.

For a high temp short draw (~1-2sec) you need a coil with low resistance and a lot of wraps. Since a large diameter coil also needs a lot of wick, which holds a lot of liquid, which acts as a heat-sink, it was better to use a small diameter coil so the evaporation would happen faster. The trade off is a small wick needs longer to recharge between puffs. One way to increase recharge rate was to increase the diameter of the wick outside the coil by adding material to the tails after the wick was pulled through the coil.

For a medium temp medium draw(~2-4sec) you need a wick that recharges a bit faster. So you need a larger diameter coil, but not so large that the volume of liquid within the coil acts excessively as a heat-sink. To achieve this a narrower coil with a larger diameter was used. The width was approximately the ID

For a low temp long draw (4+sec) You need a wick that will constantly feed while at the same time not suck up too much heat. Thus a large diameter/narrow coil works well.

Now, there are infinite variation within this basic framework but the logic still holds true.