Tensioned Micro Coils. The next step.

[MacTechVpr]

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:
View attachment 472410

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

Congrats supe, as often I've mentioned twisted's were my preferred vape in the background for the better part of two years as I evaluated clearomizer strain build methods and talked up tension for new vapers. As it happens my first authentic, a gold Trident ridin' a Sentinel/M1, is sporting a single like yours. Revived my still favorite reference standard device for tobacco just today. You must have radar. Yes sir, you can get more production out of them. For some juices, I still favor it. Hard to get the twist pitch consistent enough to attempt a contact coil. Even then 2/3 go hot with mixed oxidation results as your pic suggests but a vape I certainly still strive for one once in a while. Whenever I got one stable enough it'd go on the ZNA. And I'm with you on the preference for twisted singles. Get better results generally with straight wire t.m.c.'s goin' dual.

Good luck on this new horizon.

 

[MacTechVpr]

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

Didn't think you were. Nothin' wrong with questioning a conclusion tho.

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.

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.

I'm with you on that all the way…match the wind to the wick, power and air flow based on the device and juice. I use additional tufting as well to enhance wick saturation and to support wick contact at the end turn, help mitigate gravity sag. There's a heck of a lot of discussion on wicking but not near as much dissection of the reasoning as you have. It deserves a thread if folks could keep focused enough. If you've got the legacy thread you mention bookmarked post please so we can have at it.

Thanks and good luck.

 

[Boden]

I'm with you on that all the way…match the wind to the wick, power and air flow based on the device and juice. I use additional tufting as well to enhance wick saturation and to support wick contact at the end turn, help mitigate gravity sag. There's a heck of a lot of discussion on wicking but not near as much dissection of the reasoning as you have. It deserves a thread if folks could keep focused enough. If you've got the legacy thread you mention bookmarked post please so we can have at it.

Thanks and good luck.

Unfortunately the thread was on a forum that no longer exists. This was in 2010-11 before I found ECF.

I'll think on this, a new thread on flow dynamics might yield some new ideas.

 

[MacTechVpr]

I know, right? An idea is quite a commitment.

I know I'm not the first or only person on ECF to teach winding to a metric or using predictable resistance to hit temperature targets. There are an abundance of threads as you describe. And many members contributing to them. Each an oasis of revelation. But right you are that often they're ridiculously long. Yet worthwhile if we can just encourage folks to use the search. Ex. if you search on my handle and the concatenated "...." you'll find posts all over where I talk about how to use a pin vise to buttress end turns and control lead tension during installation. Localization, symmetry and coherence are the backbone, pardon the pun, of a tensioned microcoil.

A great discussion is how the condensed geometry and footprint of a t.m.c. can help max out the potential of any wicking media. I can see ways to accomplish each of the three principles you talk about with just the opposite wind aspect ratio using variations of wire gauge and material. Agree with you wholeheartedly that new builders need baselines like this to establish a rational center for themselves. That the days of 6 turns on 32 AWG for 2.2Ω should be over as method. We should be able to pass on simple principles for assessment to beginners so that they can find and hit performance targets quickly. My introduction of tension winding has been just that kind of yardstick effort.

Really hope B you'll stick around and contribute some of your formidable wisdom, and build a few.

Good luck.

 

[Boden]

Gosh, you sure use yer words perty

 

[MacTechVpr]

Gosh, you sure use yer words perty

LOL. Goin' fishin'. G'luck.

 

[Tmb821]

I'll just leave this here. 3/33, 26g, 1.2ohm @ 20 watts. Made on my tension rig that attaches to my drill (almost ready to show it off!)

 

[MacTechVpr]

I'll just leave this here. 3/33, 26g, 1.2ohm @ 20 watts. Made on my tension rig that attaches to my drill (almost ready to show it off!)View attachment 476817

Hey welcome T, nice job.

(Man the lag on this "new" forum. Kickin' all the campers should've sped things up. Oh well, let me kill ECF's web process again.)

Lookin' forward to the snap on that hoojiggy.

G'luck.

 

[Tmb821]

Teaser...

 

[Tmb821]

The theory is sound, but the actuality is a bit flawed. Too much deflection. I think if I have less gap in the loop it will deflect less. Anywho... Pics.

 

[Tmb821]

That's 3/32, 1.2 ohms on a istick 20w. I can take long 5 second cool vapes with tons of flavor and density.

 

[MacTechVpr]

The theory is sound, but the actuality is a bit flawed. Too much deflection. I think if I have less gap in the loop it will deflect less. Anywho... Pics. View attachment 476920View attachment 476920 View attachment 476921

T your tensioning skills have vastly improved over your first few weeks. You show how easily and effectively this can be done.

Congratulations!

I would add here that while I don't agree with Dr. Farsalinos' initial unqualified remarks about dry burning there are no advantages to pulsing our coils to high wire color temp's. It happens. You can hold a pulse a second and a blip too long but it should be avoided or kept to a minimum. Basically we don't want to over-ride the amount of energy we used to create the wind. That imprint is stored in the wire. More energy (heat) input than used to create the form can compromise the balancing stress we carefully put in and distort the wire by heat expansion. Most defects or imbalances in the wind/s or wire show up readily at lower voltages and are often masked at higher power. Further, high heat I understand can degrade the alumina itself prematurely affecting the durability of the coil. Something we don't want. So it's measured repeated low voltage pulses. We don't need high heat to form the wire into shape with compression as with a hand-wound coil. Tension has done the heavy lifting for us limiting the amount of pulsing and temperature that needs to be applied.

So I don't encourage high heat pulsing for annealing or dry burns in cleaning. It should should be avoided to preserve your durable original tension wound result. No more no less.

Glad to see you're getting there quickly!

Good luck.

 

[Tmb821]

I usually try to stay away from high heat in the forming/ annealing process. I find that low temps seem to provide a more stable vape. One that produces more volume and flavor with reduced burning of the juices. On my more flavorful, darker juices, too much heat in the dry burn stages tends to lead to a coil that burns juices easier and produces more gunk as a result of carmelization.
With tension and low pulses, I find coils run cooler and provide the same, if not more, vapor production and flavor. Also moving to a 3/32 coil from a 1/16 has been a major revelation to me. I think with the increased wick capacity in the coil, the tendency to have a dry hit is extremely reduced. I find that I am getting the performance of duals out of a single coil at lower watts, which I like.

 

[MacTechVpr]

You're a year behind me and perhaps a few winds but your observations parallel mine on micro's. A cool build is an efficient build. And yeah although in general accretion and caramelization are proportional to the amount of juice vaped I've personally found that t.m.c.'s are cleaner in the main. Some juices however particularly highly pigmented tobacco's are a challenge at any flow rate. The chemistry varies too much to single out any temp range or flow rate. So how do we get that? Make it cool. Get the vape as consistently dense through the pulse interval (in sec's). That means uniformity of surface output. What a t.m.c. does best.

On the Protank thread where I most spent time discussing tension winding the practical limits were set to 1.778mm due to the narrow wick slot. However you really need a lot more media to take advantage of the possible power concentration of a properly insulated micro. With a stable oxidized contact coil you are putting the maximum surface area to the media we can geometrically achieve. I know a lot is made of multi-wire which I happen to enjoy but one must consider how much of the overall surface of the wire is exposed to air vs. the wick. We want the maximum amount of surface emitting heat to wicked juice as possible to have both vapor and flavor in abundance. You can always design to have more diffusion internally by increasing wire thickness (aspect ratio) or with greater airflow. But it's wicking media contact that determines the potential for efficiency. So some excellent perceptions on your part as to the evident benefit of increased flow capacity on a t.m.c. You've done what it took me many hundreds of builds to get to.

Good luck T. Enjoy the vape.

 

[super_X_drifter]

This lil 2.0mm 4 strand twisted 30 ga kanthal a1 coil is really a great performer vapor wise and it's relatively high resistance. I'd guess it's about .9 ohms. Great battery life and a highly fulfilling vape.

22 mm stumpy RDA , wide open AFC, Teflon chuff, KGD and UFNB.

 

[gt_1955]

I've tension wound a contact coil using a Kuro coiler (mounted in a lathe) to these specs Coil wrapping | Steam Engine | free vaping calculators The resulting coil appears perfect, except the first wind has slightly moved out of contact whilst mounting it (in an eGo-ONE coil base).

The aim resistance was 1.3Ω but it measures 1.8Ω
Any idea why? Too much tension?

 

[MacTechVpr]

Not sure how you accomplished it but it does suggest over-tightening and resulting skew (excessive helix angle). Once the coil is elongated like that…like a "slinky" shifted sideways in your hand...it won't revert back to a natural helix angle until that sideways energy is released. When you wound it surface tension of the mandrel locked it in place. The coil may also exhibit more micro gaps than usual.

Now…raking the coil…the poolstick reinsertion of the mandrel once or more…may release the over-strain and you will see resistance drop towards spec line res as you pulse and test. You may need to a few times. Careful not to fire too hot at too high a voltage. Thanks to super_X_drifter for his original explanation of this approach.

If altogether too tight it will vape quite hot not only end-to-end but leads as well…no matter how much you rake. Easier to just wind a few more with a little less stress.

Interested in your mechanical method and hope you'll drop us a few frames.

G'luck gt.

 

[gt_1955]

I am photographically challenged (my photos always turn out blurry ) so I will describe the method instead. The process used is exactly the same as previously described in this thread using the coiling gadget but the method is different.

Instead of using a wing nut, washers and thumb screw to constrain the end of the wire, the wire is constrained in the Kuro coiler which is then wrapped with a bit a brass shim and then chucked in the lathe, securing it.

Instead of winding a crank handle thereby rotating a shaft with the wire feeding onto that shaft under tension, I rotate the chuck by hand with the wire feeding onto the coiler's spigot under tension.

It's quite likely that it is over-tensioned, as I pulled the spool of wire towards the chuck (that is, the feed-in angle was approximately -10 degrees assuming the helix angle of the coil is positive). One thing for sure is that it will not deform out of contact with its neighbouring coil on its own accord, so micro gaps are highly unlikely (other than wire abnormalities) and certainly not visible under 20x magnification.

I did "rake" the coil several times with little effect. But the coil and legs do not run hot, the coil works very well in the device (a variable wattage eGrip so coil resistance is non-critical provided it's greater than the minimum allowed by the chipset) and it is just annoying I missed my target resistance.

I might try less feed-in angle next time. Thank you for your assistance.

 

[MacTechVpr]

Seems like you have a sound plan gt. I knew someone would find a use for these things.

There's a happy place between too loose (gaps result) and too tight (excess internal stress is stored energy or heat). Then on either side of this Goldilock's Zone the wire goes too hot. It varies with gauge. When you've nailed it uniform oxidation occurs very quickly at low voltage. Too tight and you progress too quickly through oxidation. A difference discernible as you start to associate the resulting oxidation wire surface colors with your results. So it's a learning process on the oxidation side. With a t.m.c. insulation uniformity is the goal that'll lay down the most heat on the wick. It's the optimal of insulation that we're looking for to attain temperature output stability. Just enough to complete the circuit at your anticipated power level. Higher power levels may require more pulsing with greater power. And that will depend on where you want to be. High power builds usually imply greater wire mass and naturally will require more energy and firing to insulate.

Best of luck gt. Keep us posted and still would love to see a pic if you can sometime.

 

[dDubs]

sXd, I watched a couple of your YouTube videos after finding this thread and got myself a coil gizmo and the thumbscrew/wing nut mod. I have tried and given up on building several times but last night I made my first coil that actually works well!
Using my mutation x v4 that I just got, I used 24g kanthal on the 1.5? mm rod, six wraps, and got .4 ohms I believe. Set it up, used your method for alleviating hot legs, and it vapes amazing! Thanks! I can't wait to pull apart my airek clone after work and try a twisted wire setup.. But I only have 24g, and some 32g wire from back in the day. Maybe I'll twist up some of the thin stuff, or anyone have suggestions for me?