Coils. Not as easy as they look

[Darth Omerta]

I sub Ohm all tge time. I vape at 8-10 watts on a .8 ohm coil. My short kayfun gives a nice cool vape.

8 wraps on a 2 mm diameter
6 wraps on a 2.5 mm diameter

Both 26 gauge.

Hot vape is caused by big watts or the airflow being almost closed and not enough airflow to cool tge the coils.

I might disagree with some of that. IMO 10W is a bit too cold for a .8ohm build with 26AWG, but if thats how you like it then by all means. For me the perfect setting for a .8 would be around 15W-18W which is right dead center of the "green zone" using the heat flux calculator on steam engine(around 200mW/mm^2 (milliwatts per millimeter squared))

Conversely, Im currently vaping at .3ohms on my Lush with dual coils using 24AWG. Im vaping at 50W and even thats a little cool coming in at around 186mW/mm^2. Ive also got setups at .6ohms and 1.3ohms. The wattage I use on regulated mods is dependent on the heat flux for my particular build. When using my mechs I make my build based on what will have a decent heat flux(170-210 is my range). Making a good build for a mechanical mod in a safe manner adds the challenge of calculating your heat flux as well as applying Ohms Law, which often results in several trial and error calculations before actually wrapping a coil. It can be a PITA but its well worth it if you're a mech user!

Hot vapes come from pushing unnecessarily high wattage through your coils. The more metal you are using the more power it will take to heat it up, if you've got thick guaged wire and are running 2 or more coils it will take more wattage to stay around 200mW/mm^2. If you are using dual twisted coils(for this purpose Im keeping the 24AWG and .3ohms) then you might need around 200W to get the same heat flux.


Here is another thread discussing heat flux, @State O' Flux and @readeuler give really good explanations of it....well worth a read!
Heat flux

 

[kiba]

I have a lot to learn. Care to elaborate. Or point me in the right direction?

www.steam-engine.org

 

[Two_Bears]

I might disagree with some of that. IMO 10W is a bit too cold for a .8ohm build with 26AWG, but if thats how you like it then by all means. For me the perfect setting for a .8 would be around 15W-18W which is right dead center of the "green zone" using the heat flux calculator on steam engine(around 200mW/mm^2 (milliwatts per millimeter squared))

Conversely, Im currently vaping at .3ohms on my Lush with dual coils using 24AWG. Im vaping at 50W and even thats a little cool coming in at around 186mW/mm^2. Ive also got setups at .6ohms and 1.3ohms. The wattage I use on regulated mods is dependent on the heat flux for my particular build. When using my mechs I make my build based on what will have a decent heat flux(170-210 is my range). Making a good build for a mechanical mod in a safe manner adds the challenge of calculating your heat flux as well as applying Ohms Law, which often results in several trial and error calculations before actually wrapping a coil. It can be a PITA but its well worth it if you're a mech user!

Hot vapes come from pushing unnecessarily high wattage through your coils. The more metal you are using the more power it will take to heat it up, if you've got thick guaged wire and are running 2 or more coils it will take more wattage to stay around 200mW/mm^2. If you are using dual twisted coils(for this purpose Im keeping the 24AWG and .3ohms) then you might need around 200W to get the same heat flux.


Here is another thread discussing heat flux, @State O' Flux and @readeuler give really good explanations of it....well worth a read!
Heat flux

I'm using a Kayfun with a single 2 mm coil. Push a lot of watts through that and you burn the wick at 12.5 and up.

If i was using dual coils i would be using 15-20 watts.

 

[Darth Omerta]

I'm using a Kayfun with a single 2 mm coil. Push a lot of watts through that and you burn the wick at 12.5 and up.

If i was using dual coils i would be using 15-20 watts.

I realized you were using a single coil based on the number of wraps and guage. I dont use RTAs so I cant speak for how fast your wick draws more liquid in but for a single coil at .8 ohms the 200mW/mm^2 "sweet spot" is around 18W. Again, Im not saying that this so called "sweet spot" is for everyone, and if you enjoy your vape at the wattage you use then nobody(myself included) should try to mess with it. I wasnt disagreeing with your personal settings and setup, to be honest "disagree" might be the wrong word for it as I was more expanding on what you were saying about the mass of the coil. All Im saying is, if you factor in heat flux on your builds and wattage settings you can vape at wattages that some would consider "high" and still not experience the spatter and burning lips/tongue.

 

[Two_Bears]

I realized you were using a single coil based on the number of wraps and guage. I dont use RTAs so I cant speak for how fast your wick draws more liquid in but for a single coil at .8 ohms the 200mW/mm^2 "sweet spot" is around 18W. Again, Im not saying that this so called "sweet spot" is for everyone, and if you enjoy your vape at the wattage you use then nobody(myself included) should try to mess with it. I wasnt disagreeing with your personal settings and setup, to be honest "disagree" might be the wrong word for it as I was more expanding on what you were saying about the mass of the coil. All Im saying is, if you factor in heat flux on your builds and wattage settings you can vape at wattages that some would consider "high" and still not experience the spatter and burning lips/tongue.

My tootling along at 8-10 watts with a .8 ohm coil works for me.

 

[93gc40]

I don't remember elementary school physics lol. Think I daydreamed too much.

Yeah, I know what you mean.....

Good thing is with a calculator like Steam-engine and a regulated mod and a forum like this ... We don't really have to relearn all that stuff, anymore. Once you learn where the safety limits are for the device you are using at the time.

Sent from my SCH-I605 using Tapatalk

 

[fiddleshe]

I looked at steam engine. But I'm an idiot. I don't understand what some of the things I'm looking at are. Like how do you measure leg length. Where exactly does the leg start? Is that before or after you cut off the excess? Does it include what is wrapped around the posts? If so how do you measure that?
In the results all I understand is resistance. I don't know what any of it else means.

 

[fiddleshe]

Also Ive already built probably 10 coils with 32 gauge kanthal. I have broken a few because the wire is thin. Some people have suggested 26 gauge wire. I always forget on gauges the lower the number the thicker the gauge or wire? If so that would be better and I'll order some new wire.

 

[Darth Omerta]

My understanding is that the leg length is measured from the post to the point where the coil starts to wrap. I dont adjust this number beyond the default of 5mm, at most you will be off by 1mm which has very little effect on the results. For beginning purposes with Steam Engine the most important fields to learn are: Material and Profile, Diameter of Wire, Setup, Target Resistance, Inner Diameter of coil, and learn how to read and assess the results.

In the results panel you will notice the heat flux calculator, you can adjust the wattage and it will give you a range of 3 colors, blue = "too cold", green = "just right", and red = "too hot". These are guidelines and once you find the "green zone" for your build, you should ABSOLUTELY tinker with the wattage on your mod to find your preferred vape.

 

[Darth Omerta]

Also Ive already built probably 10 coils with 32 gauge kanthal. I have broken a few because the wire is thin. Some people have suggested 26 gauge wire. I always forget on gauges the lower the number the thicker the gauge or wire? If so that would be better and I'll order some new wire.

Personally, I liked 28AWG when I was starting out. I use different guages depending on the type of build Im looking for and which mod I will be using, as well as what type of vape I want(I do everything from tootle puffing to clouding all on drippers lol). Thicker guages require more wattage to get to the "green zone" but are easier to wrap, thinner wires heat up fast and dont need high wattage but they can be a little finicky for wrapping as they can tangle easily if you're not careful. You are right that the higher the guage the thinner the wire. 22AWG is the thickest Ive used and 32AWG is the thinnest.

 

[fiddleshe]

The heat flux info is helpful. Ive been just guessing. And guessing wrong.

 

[fiddleshe]

I just ordered some 28 and 30 gauge kanthal based off of playing with steam engine. Wire is cheap. I will see which one I like better.

 

[Carl2]

I got into coil building after my Kanger atomizer went, so I bought atomizers for it and also an RBA with wire. Since I use temp control I started out with nickel wire and needed a resistance of .15 ohms. I ended up with 2 32 gauge twisted nickel wires. Steam eng is not mentioning twisted wires so it's not useful to me.
As far as flavor production I've also switched to making my own e liquid, I personally just stay with the different tobacco flavors available. It's unbelievable the amount of flavor you get by making your own liquid. You'll end up saving money and have a better liquid.