Micro Coils- Sharing heat vs. lowering resistance

[UncleChuck]

My initial, and current view is that their superiority simply comes from the fact that the highly compact coil (in both diameter and wrap spacing) will hold the heat better than a larger diameter, spaced coil.

I've seen some people suggest that micro coils offer superior performance because the touching coils allow the current to pass straight across the coil, instead of around the coil, lowering the resistance but still maintaining very high surface area.

This really made no sense at all to me, and I'll tell you why:

Look at your coil. Now take a piece of kanthal that is the same length as your coil (probably 1/8" to 1/4" long depending on your wraps. Now measure the resistance of that piece of kanthal. What is it? .1 ohms if that? (again, varying depending on wire)

Now compare the thickness of that single piece of kanthal, to the thickness of the metal "tube" that is the microcoil. If current was being passed directly from one wrap to another across the coil, as some suggest, micro coils would meter under .1ohm. Obviously that isn't the case.

Another thing to consider, is that it seems highly unlikely that you are going to be able to get every single last bit of surface area between the coils to be touching each other in an even, complete way. Without doing that, some wraps will pass current directly to the next one instead of around it, while others will pass around, leaving a mess of hot spots (assuming current is actually being passed wrap to wrap)

I took out my attys with microcoils, checked the resistance. Then using a dental pick I ever so slightly pulled the coils apart to ensure zero touching. Checked the resistance again, an no changes on any of them (well, no changes within the ability of a zmax to detect) Seems pretty conclusive that at least MY builds are not passing current directly from wrap to wrap, yet still retain all the advantages of a microcoil.

I'm not trying to attack anyone's ideas here, when I hear something that puzzles me I just have to bring it up. What say the MC junkies here?

 

[Spazmelda]

I don't really know, but I'll add my experience. I don't have much experience building micro coils yet. I've made a few and some work, but some have trouble wicking. I've still got to pin down the right amount of wick in there.

Anyway, the first time I tried to make one I was going with that idea that the coils touch so resistance will be lower. Using that logic I made a coil out of my usual kanthal at 32 gauge. On a normal coil (protank) I'll do 6 wraps with 32 gauge and get 2 ohms, on the dot. With them touching, and since I thought the resistance would be lower, I did something like 9 wraps. The resistance was very high. I can't remember exactly but over 3 ohms. Now, maybe this is due to my inexperience with micro coils. Maybe I only thought they were touching. I squeezed them together and torched them and with my super strong old lady reader glasses on they looked like they were touching, but maybe they weren't.

 

[Orb Skewer]

Electrons follow a path of least resistance, so in the case of coils that is through the wire as opposed to across a an adjacent coil, coils though they are touching are not an ideal conductor, they will be dirty and have deposits on them-even when new, and if you looked at the wire in cross section it would look like this > oo , again-not a path that is easier for electrons to travel than this > -----------

Heat induced in tightly packed coils will be more focused than that of spaced coils.

 

[super_X_drifter]

I too believe their efficiency is in part because the HEAT passed across the tight / touching small diameter loops.

The loops being so small and close / touching possibly allows them to work in concert to heat up and transfer and share heat between themselves?

Dunno. I'm prolly the last person who could say why they work so well

I was also thinking about hydrology when I started to wrap them thinking that with a thick wick in a thick coil the juice would tend to saturate the bottom of the wick, leaving the top drier? Again, dunno but I can attest that they vape much better than old school coils.

Many users also report that they stay much cleaner than spaced coils. I can't say cause I vape high VG ratio unflavored nic base - everything stays clean with it

Some small random gaps are ok, even though the ones that to the naked eye / camera appear touching are what we are shooting for - like this one:

Good call OP.