Standard vs. "MicroCoil"

[acidrayne280]

I have thus far been unsatisfied with the vapor production of my Zenesis 2. I have been using 3/4 wrap of 28g wire. I keep seeing these microcoil builds with the coils touching and want to give it a try....but I thought if the coils touch, that constitutes a short.....looking for some advice.

 

[State O' Flux]

I have thus far been unsatisfied with the vapor production of my Zenesis 2. I have been using 3/4 wrap of 28g wire. I keep seeing these microcoil builds with the coils touching and want to give it a try....but I thought if the coils touch, that constitutes a short.....looking for some advice.

When heated, Kanthal wire (iron-chromium-aluminum) builds up an aluminum oxide insulative coating on it's outside surface that protects the individual coils from shorting, one to another. This is called alumina (Al2O3).

This is most clearly noticed when you test fire a new compressed coil... the coil initially shorts and heats unevenly. The more you fire it (and shape it to final perfection) however, the more evenly it will heat - from the hot center out to the cooler ends.
This is the alumina layer developing and insulating the coils surface. Although the coils are "touching", the electrically conductive component of the coils are insulated by the alumina coating.

That is it. No magic... unless a self-generating, protective oxide layer is considered magic. Maybe it is magic - Kanthal wire is both thermally conductive and electrically resistive. Pretty convenient for us, and several billion other handy applications for heating coils.

 

[acidrayne280]

Awesome, thanks for clearing that up. I have wanted to try one of these builds for a while, but just looked at it thinking "that's gotta be unsafe". Am I safe to test fire something like this on a my zenesis (I use IMR batteries only) and how much shaping is needed....or is there a write up for all that?

 

[madangus]

Theres a bunch of good videos on youtube for doing at leadt the basic micros

 

[DoubleEwe]

The main reason for getting little vapour from your build is that you are using far too few wraps with 28AWG.
The majority of vapers using that gauge would use 8wraps per coil. (2mm diameter)

That build will be fine on a mech, and obviously fine on a regulated mod too.

There is really no need to opt for touching coils, spaced work well (or better IMO), it is all about personal preference and whatever you find easiest to do.

 

[Mr.Mann]

The main reason for getting little vapour from your build is that you are using far too few wraps with 28AWG.
The majority of vapers using that gauge would use 8wraps per coil. (2mm diameter)

That build will be fine on a mech, and obviously fine on a regulated mod too.

There is really no need to opt for touching coils, spaced work well (or better IMO), it is all about personal preference and whatever you find easiest to do.

And to add to the @DoubleEwe point, your wicking makes (IMO) as much of an impact on your performance as the coil (and maybe even more). The two go hand in hand, or rather, wick in coil -- but you get the point. LOL. The wicking is very important, but unfortunately conveying the proper amount over the internet (even in videos) is almost impossible. You just have to find the right resistance of how it feels going into a coil.

Often times poor wicking will make vapers think the problem resides in their coil when it's really the fault of the wick. WIcking was my toughest hurdle to clear with rebuilding. I still occasionally struggle getting it just right, but it's more about me knowing what "just right" really is. I won't settle for shoddy wicking, but I can still achieve a great vape with shoddy coils if the wicking is perfect! (Note: I prefer pretty coils though so it's rare that I keep janky looking coils under my hood even if I know they will perform great.)

Oh, and where your coil and wick are located in respect to the air hole can make for completely different performance outcomes. So many little factors.

@Jimi D. uses spaced coils and ribbon wire with silica wick. He is a bonafied cloud chaser with the best of them, and he is likely one of the few that is using a more old school wrapping/wicking set-ups. You can do a lot with 28 gauge, but you can't wrap it as if it's 24 gauge.

 

[DaveP]

22 ga Kanthal wire with 8 turns on a 3mm coil form works for me to get into the 1.8 to 2 ohm range. As was mentioned up topic, a dry burn creates an oxidation layer that insulates the coils from each other. I like to use a 510 base ohm meter to hold my coil while building. If you check the resistance right after winding, rubbing it with a fingernail will make the ohm readings vary wildly. Take the coil deck off and dry burn it on a mod, then install it back on the ohm reader and it's stable when you rub it with a fingernail.