help determineing wire size for coil, first timer here.

[FilterLess]

I am trying to determine what size wire I need to order so I have everything I need to get started. Being new believe me, it is harder for me to find a way to say it than it is for you to figure out what I am trying to say

This is how I am doing it, please correct any errors and suggest an easier way if possible.
What I want to do is make the needed dual coils for an IGO-W dripping atomizer (RDA I think). End result I hope to have a 1.3 to 1.8 ohm resistance on the device. If I am reading everything correctly (there is doubt here) then I am looking to make two 3ohm coils to allow myself a little margin for error either way.

Narrow down options....
Kanthal A-1 has the highest resistance per inch so I chose it at 28 gauge for this example.
I have a 2mm drill bit I special ordered and never used so no chuck scaring and will use that as a size base.

The math (not my best subject, was always good at lunch tough) rounded...
Pi x 2mm = 6.28mm so 6.28mm around the drill bit.
28g Kanthal is .32mm thick so the radius is .16mm
.16 x 6.28 = 1.0 adding that to the 6.28 I get 7.28 to find the center of the Kanthal wrap and a closer estimate of length needed for one wrap.
Multiply that by .04 to convert to inches and I get .29, divide 1 by that and find I need to make 3.4 wraps to use an inch of Kanthal A-1 28g @ .46ohm of resistance.
Divide the desired 3.0ohm by .46ohm and find I need 6.5 inches, 6.5 x 3.4 = 22 + or – to allow for tails to connect with.

So best guess, 12 wraps would allow me to have two 1/4 inch tails but only produces a 3.4mm wide coil (thickness of two quarters stacked) if the math is correct.

You're asking why I did this the round about way?... because I also want to ensure I have a wide enough coil to contact the most juice.

Am I doing this even close to correct? If so, I assume I will need a smaller gauge wire to cover more area.

 

[Btsmokincat]

12 wraps with an ID of 3.4mm! That sucker would be huge! I'll have to try that someday.

According to my Vaper's Toolbox android app... 28 gauge with an inner diameter of 3.4mm shooting for 3.0 Ohms with .25 inch leads will require 8/7 wraps.

If you have an android device go to the Google Play store and get "Vaper's Toolbox" it's free and was made by a member here. It simple and works awesome and has always gotten me within .1 to .2 ohms on my builds.

 

[Btsmokincat]

Let me add the Vaper's Toolbox app lets you choose Single and dual coil as well. When I change the settings above to dual coil and 1.5 Ohms it comes out to... (drum roll please) 12/11 wraps!! Filterless your math is spot on for a dual coil! Nice job!

 

[FilterLess]

sadly no android so i have to do this old school. Guess the math is off. But the 3.4 is what i determine to be the ending width of the coil, 2mm ID. So it doesn't seem to be covering enough area to me.

 

[Btsmokincat]

Oh boy I hope you see my second post! I feel terrible for making you think your math was wrong. It was completely right. So sorry!! The app makes different calculations between single and dual coil builds. I'm liking your above post so hopefully you'll come back and see this!

 

[FilterLess]

thanks, downloading bluestacks and will see if it will let me use the app on my desktop, question... is a 3.4mm wide coil going to be wide enough to create vape?

 

[Btsmokincat]

I don't know if I dare answer that

What are you using for wick? If it's cotton as long as you fill the coil snug not too tight or too loose it should vape fine. If you haven't drilled out the air holes on the Igo-w you may want to think about that. More air = more vapor!

 

[FilterLess]

as will be my first coil ever looking at something easy like a dragon coil. Juice (if it makes a difference) is 100% VG..

There is alot of apps listed under Vapor but no toolbox, maybe limited to Phone apps.

 

[Btsmokincat]

Looking back over all of this I think you may want to do a higher gauge wire so you can make a smaller diameter coil. I use 1.4 mm diameter for Kanger head rebuilds and 2 mm for my RDA builds. I think a 3.4 inner diameter coil may be slow to heat up.

30 gauge dual coil, 1.5 target resistance, 2.0 mm inner diameter with .25 inch leads requires each coil to be a 12/11 wrap

change it to 32 gauge and the wraps drop to 7/6.

 

[Btsmokincat]

as will be my first coil ever looking at something easy like a dragon coil. Juice (if it makes a difference) is 100% VG..

There is alot of apps listed under Vapor but no toolbox, maybe limited to Phone apps.

As far as I know it's only on the Google Play store. It's vaper's toolbox (vapEr spelled with an "E") if that makes any difference.

Are you talking a dragon coil build like this:
Nano Dragon Coil Build - YouTube

 

[FilterLess]

Haven't seen that video but yes. as for coil ID, using a 2mm drill bit should give me a 2mm ID. the 3.4mm you are referring to is the width (or length) of the coil (depending on perspective). looks like it might be easier to just buy the needle he is using in the video. thanks

 

[Btsmokincat]

Haven't seen that video but yes. as for coil ID, using a 2mm drill bit should give me a 2mm ID. the 3.4mm you are referring to is the width (or length) of the coil (depending on perspective). looks like it might be easier to just buy the needle he is using in the video. thanks

Well that explains alot!! I kept picturing a coil big enough to drive a bus through!

 

[FilterLess]

WOOHOO, got the app on my desktop. doesnt tell me wraps but tells length of wire, still playing with it though, thank you..