EVOD stock coil and wick -- reverse engineered and the numbers

[Mad Scientist]

Making a "factory stock" replacement coil and wick for the EVOD can be frustrating or a snap. Here's how to get the factory performance or better, without tearing your hair out:

The subject: a stock, factory made 2.5 ohm head.

The numbers measured as carefully as practical:
Wick: 2mm rope silica.
Wire: .25mm (i.e. 30 AWG), metallurgy unknown.
Coil ID: 1.55mm, coincidentally, very close to 1/16"
Coil OD: in the range of 2mm to 2.1mm (hard to measure accurately).
Flavor wicks: 1mm rope silica.
Coil Wraps: 6.

So with the above data, how to do it fast and easy. Wrap the coil on a 1/16" drill bit -- it is so close to the stock coil inside diameter as to be one and the same. Carefully thread a 2mm rope silica wick through (its easier if you wet the silica with some juice first). Coil the head in the usual manner. Add one or two 1mm rope silica flavor wicks, as works best with your juice. if you only use one, "flay" it so it fills the top corners of the wick opening in the head. Trim the wicks. Done. Incidentally, all the foregoing is nearly impossible for me to do without magnification. If you want to work on wicks, get one of these: Magnifier Lamp 5X Lens Swing Arm Light Facial Fluorescent Clamp Mount Magnifying | eBay

Using the above method delivers a top performing wick time after time, just like factory new. I use 30AWG Kanthal A-1 and end up with a coil measuring around 2.0 ohms every time.

 

[Mad Scientist]

Making it easier to thread the wick into your premade coil: make the coil as above; place one leg in something to hold it steady (I use one of those "helping hands" things with the two clips mounted on a base); carefully torque the other leg slightly in the opposite direction of the wraps, not enough to overcome its springiness, but enough to open up the coils while held this way; thread the wick; let the coil sping back to its original shape around the wick -- if it doesn't spring back, torque the leg with the direction of wraps to return it to its original coil diameter.

The key to a consistently good performing head is a consistent coil diameter. This gives very close resistance for every coil and more importantly won't "choke" the wick being too small, or develop bad hot spots being too big. Just right every time.

 

[DavidOck]

A wrap of teflon "plumber's" tape around one end of the wick also works well for threading. You can pull it to a tight and tiny tip, and it comes off easily.

 

[440BB]

Thanks for the good ideas! I just started using Evod coils and like this approach to get consistent results.

 

[Mad Scientist]

Will try the Teflon tape trick. Thanks

 

[umanbean]

THANK YOU! for this concise yet completely thorough description. And thanks to David0ck for the "ttt" (teflon tape tip).

Off to get some 2mm silica and 30g Kanthal.

 

[DavidOck]

Ah, you're welcome, but I'm just passing it along. Read it somewhere else here on ECF

 

[SupplyDaddy]

Kewl, been doing basically the same thing for the T3 and T3S coils, using 32 ga Kanthal, 5 wraps for 2.0 ohms

 

[Mad Scientist]

No problem. I was getting frustrated not being able to just whip up a new wick & coil that I knew would work just right every time. I pulled out the calipers and decided to find out exactly what it was about the stock ones that made them work the way I like. The coil is "looser" than I was making and it needs to really just touch the outer diameter of the wick, but obviously not too loose. 1.55mm ID is the sweet spot. Also I was surprised that they were using 30 AWG wire. They obviously spent some time on it because if I make one just like they do at the factory, I like it.

I have found that coils just ad hoc wrapped around a wick or even using a spacer of some sort as everyone seems to do in every youtube clip I've seen, are just not consistent enough.

 

[DavidOck]

I find wrapping my coils on a 4-40 machine screw keeps the spacing nice and even. And "torching" the kanthal first (I just us a butane lighter) helps with the springiness.

Like SupplyDaddy, I prefer AWG 32 and 5 wraps, but it's really just a matter of taste. Slightly higher resistance gives me more adjustment on my Vv/VW devices, to fine tune for different juices.

Thankfully, we're all different. Be pretty boring, otherwise

 

[Mad Scientist]

A wrap of teflon "plumber's" tape around one end of the wick also works well for threading. You can pull it to a tight and tiny tip, and it comes off easily.

Wicked another set of EVOD heads today and used your Teflon tape technique. Nothing short of pure genius. I can't imagine how you came up with that, but it is a prize winning idea.

I made a couple coils with split wraps, similar to the stock heads. Four tightly spaced wraps (a/k/a the microcoil thing) a little space, then four more wraps. Supposedly keeps the heat more towards the ends of the wick with a bit less in the center where it's dryer. Haven't had the chance to vape it yet, but hopefully worth the bit of extra effort. Then again, that Teflon tape thing makes the toughest part of the process a breeze. Thanks again for sharing that idea.

 

[DavidOck]

I'd like to claim it, but I actually read it here on ECF some time ago, and tried it. Wish I could remember who should get the credit, 'cause it does work so well!

Another trick that works if you're lacing a doubled wick - as I sometimes do if using cotton (or stupidly ran out of the right sizes... ) is to use a "floss threader" of the type used for those with bridge work. Cheaply available in any pharmacy dental section. They're ultra thin plastic needles, and easily fit inside the coil.

 

[dr g]

Wire: .25mm (i.e. 30 AWG), metallurgy unknown.

How did you measure this wire? 30 gauge resistance wire will not give you 2.5 ohms for a coil of that size. When I measured my coil (admittedly a clone head) it had 30 gauge NR legs and something like a 34 gauge coil.

 

[Mad Scientist]

How did you measure this wire? 30 gauge resistance wire will not give you 2.5 ohms for a coil of that size. When I measured my coil (admittedly a clone head) it had 30 gauge NR legs and something like a 34 gauge coil.

I measured it with a caliper that is accurate to .0005". I don't know what the metal composition is, but given its resistance it is definitely not Kanthal. It is also definitely monolithic -- one piece of wire.

 

[Butters78]

Great info!

It's also fun to try different methods. For example using ss mesh, or a microcoil with cotton.

 

[dr g]

I measured it with a caliper that is accurate to .0005". I don't know what the metal composition is, but given its resistance it is definitely not Kanthal. It is also definitely monolithic -- one piece of wire.

Interesting that you would have the NR leg construction with a clone head but not the genuine head.

 

[Mad Scientist]

Interesting that you would have the NR leg construction with a clone head but not the genuine head.

I don't claim to have ever found a hybrid wire ... I think that was you.

 

[dr g]

I don't claim to have ever found a hybrid wire ... I think that was you.

Yes I found that wire in my clone head. That's what I'm saying, interesting that the clone would have that kind of wire but the genuine head would not. Got some genuine heads slated for rebuild also so I'll confirm on my end.

 

[SupplyDaddy]

Kanger does not use NR wire for the Evod, T3/T3S or Protank coils.