Kanthal gauges, wraps, and coil heat up time?

[CodeRage]

Since I am a new member, I have to improperly post this under new member forum rather than rebuildable atomizer forum like I wanted.

Since I tend to be a motormouth (or motorfingers as is the case here), i'll break up this post in sections so you can skip the boring historical experience stuff and get right to what I am after today.

Historical Experience

I have been vaping for 2 or 3 years now (after having smoked analogs for 23 years), progressing from ineffective cigarette sized (Blu, Volcano), to cigar sized (Inferno), and settling on a noggin knocker (Lavatube v1 and v2). My vapegeeking has also gained some traction and is now delving into rebuildable atomizers.

I have an aga-t2 set up with an ss #500 mesh wick (fully oxidized, following pbusardo and various others' tutorials including ECF posts), powered on a Lavatube V2. I initially got (I believe) 34 ga. kanthal wire along with the standard mesh and whatever wire that came with the aga-t2. My first experiences with this set up was borderline on disappointment, more so with my lack of experience, skill, and knowledge on this (which mostly comes from experience to be honest). The resistance on 34 ga. scales up fairly quick, so my first 4/5 wrap ended up around I think 2.8 or 3 ohm. I wasn't happy with this resistance because it wasn't vaping fast enough for me, and I don't particularly care to jack up voltages to achieve this as I tend to burn juice rather than vaporize it (DIY juice, which I also think I need to gain more knowledge and experience in too :-/ ).

So I did more research and settled on ordering various gauges of kanthal a-1 to work with. I just got 28, 30, 32, and 33 ga. wire in the mail today, so i'm veekin (vapegeekin) and ready to play. However, being that I only have 3 ft of each gauge to work with (tons more on 34 gauge spool, but not interested in working with that for now), I want to be a little precise on what wire I go with for my next coil I build, and minimize wasted wire.

What I am after!

What I am after is an understanding of the rate that a length or wrap ratio of various gauges of kanthal coil will heat up. I am desiring to fulfill my need for instant gratification and get as much vapor as fast as I can suck on that big stick (calm down you pervs!). Currently we have to slowly draw the vapor out due to air flow limitations and vaporization rate, which I suspect is directly proportional to the coil heat (wattage, volts, ohms all considered but i'm not delving into that for now), and limited by the max vaporization rate before actual burning of juice occurs. Obviously increasing voltage or power can assist in that, but I also want to select a gauge and wrap ratio that will heat up fastest for whatever voltage I favor.


Details Pretty Please?

So, given that, has anyone (with deeper financial pockets than I) done experiments with various gauges and wraps of kanthal under various voltages (and power if you have one of those mods, which I don't yet) to expose the rates that the coil will heat up and how to control that rate? If you have, please post your details (voltage/power, gauge, wrap ratio, and observed time to full coil glowing (as in dry burns). I think if I get the coil to heat up faster, I should be able to get more vapor faster (yes the air hole size will come in later, but for now I my aga-t2 is stock, no mods done to it) and be a happier vaper.

FYIS:

FYI: I'm definitely liking the ss mesh setup. The wicking is great, and in my 3rd tank refill now it is doing pretty good. I am currently running doubled up 34 ga. kanthal running around 1.6 to 2.2 ohms depending on how moody my lavatube v2 ohmeter is being. I think i'm going to try running 30 ga. up to around 1.5 ohms in a few minutes and give that a whirl for a while. Later on down the road i'd like to get some ribbon wire so I can get even more surface coverage. I want that mass vape fast I tell ya!

FYII: I also want to toy around with the ss rope wick sometime as has been thoroughly discussed in ECF somewhere...

Conclusion:
Clearly it is time for me to hogtie my fingers cause i'm sure I lost some of ya a mile or two of verbage ago. Thank you for taking the time to read this sea of words, and it is a pleasure to finally speak out on ECF rather than just lurking and gobbling up info.

Sincerely,
CR

 

[Shaunbay2]

32g kanthal with 4 wraps? Thats what i do.

 

[Kanj.nguyen]

Im about to sleep so can only do the math in my head, but according to the mathematics, the same length of wire at the same voltage should be at the same temperature regardless of what gauge.

Also according to my head math the time it takes for each wire gauge is reach the same temperature is the same, under the same voltage.

Vapor production, however, is not dependent on temperature. It is ultimately dependent on heat input, provided the wick is able to keep up. Thats why generally 28awg produces vapor faster than say 30; the energy output is larger in 28 (even though temperature is the same), and given the same rate of heat transfer from coil to wick, 28awg gives more heat to the wick.

Keep in mind that there are many other factors. One of them is this rate of transfer that we fix at constant for simplification. Theres also distribution of heat (ribbon vs round etc.). Another oversimplification we made is to assume that the wick can keep up, while we all know getting good wicking is an on-going headache among RBA users. And then there is time spent at optimal temperature (hence air hole sizing) and all that...

Too much physics to do just in my head. Time for bed,

 

[JeremyR]

Have you looked at closely spaced touching coils. Or micro coils, in the rba section. I find the closely spaced Touching coils to be where its at. I am looking for the same thing as You are. Try a Wrap the with the coils nearly touching each other. I usually prewrap on something for these to get a really nice coil, then thread in wick. With a little juice added they become oxidized and don't short at all. They heat up faster.

 

[CodeRage]

Thanks for the input folks. I really appreciate it.

Re JeremyR: I have seen, but not read the microcoiling. I have thought about preforming the coil on a drill bit or something in order to get that form right. Unfortunately I have noticed my mesh wick tries to unwind minutely, but enough so to where the fit in the wick hole is more tight than snug (after expanding a bit, then I re-tighten the roll and put it back in when I do a new coil). I don't notice any wicking issue from it though (fill hole is plugged too).

Re Kanj: The physics stuff is interesting to me too, albeit insane mathematics. I always see math and .... as brain cookers in different ways. With regard to the 28 ga. and faster temperature output, I read somewhere (on ECF maybe?) about someone doing 8 wraps and only getting .9 ohms out of it. I have to hit somewhere near 1.5 ohm I think in order for me Lavatube V2 to fire. If I did my math right, I think i'd have to wrap around 2.5 inches of 28 ga from neg to pos posts to get near 1.5 ohms based on roughly .5 ohms / inch resistance for 28 ga. If I am assuming right, the more distance the energy has to travel, the longer it would take for that coil to heat up. It would be like the false sense of security taunting my need for instant gratification. :-/

Re Shaunbay2: The 32 ga. at 4 wraps sounds to me like it won't cover as much surface as I want. I am approaching this from the view that more surface covered by hot coil will increase vapor production. Granted "less is more" could certainly hold true in this case as well. I will have to experiment to see what works better for me.

I think tomorrow i'm gonna use the 30 ga for a new coil and see what I end up with wrap wise. So far the parallel 34 ga coming in around 1.6 - 2.2 ohms is performing decently. I have it wound up to resemble ribbon wire.

 

[sailense]

For the best heat, you want to control 2 things: power and current.

So, let's take two different setups:

Setup A
1.5ohm coil
3.7v
Power = 9W
I = 2.46A

Setup B
3ohm coil
5.2v
Power = 9W
I = 1.7A

So, both setups are producing 9W of power in the form of heat, but the lower resistance coil has much more current going through it. More current means the wire heats up faster and that's why lower ohm coils have a hotter draw even though both are giving out the same Wattage. Since 28g wire has lower resistance per inch than 32g, this is why 28g produces vapor faster than 32g.

But that's basic stuff that you probably already know. The other main factors are surface area and air draw.

Surface area is pretty easy. The more coil you have in contact with the liquid, the more vapor you will get. This is why people wrap quad and octo coils: to increase the amount of coil in contact with liquid. Now, larger wire also has more surface area, but I don't believe the increase in surface area with the sizes we're using–like, say, the difference between 32g and 28g–will make a noticeable difference. The key is how many wraps you have total in contact with the wick/liquid.

But in addition to that you need air flow. (Note: the following is conjecture based on what I believe is happening. Please let me know if I've erred.) If the liquid vaporizes but is not drawn away quickly enough, the air around the coils can get saturated, leading to a pressure increase and raising the boiling point of the liquid in contact with the coils. More air holes will draw the vapor away from the coils more efficiently and end up producing more vapor.

 

[JeremyR]

Once you get good heat, you need more air flow. I actually opened up the air holes on my protank a little to get even more air. Getting huge clouds. If I crank the voltage and unscrew it to make it super airy u can get some huge clouds in 3 seconds. But you have to be carefull you don't go too big on the air flow because it will reduce flavor if you over do it.

I just made a really nice coil of 32, all I got, on protank. Used a round toothpick to wrap on. 6/7 wrap really close. Hold it tight . Made one twist of legs to hold tight glowed it on the stove pinched the coil tight quenched and repeated. It takes 3 mm silica, I space out the touching coils with a needle, just to the distance of the needle. Like a feeler gauge between the coils. It's 2.2 ohms. If I crank it to 15 watts and have the protank screwed out to get a lot of air. I get a really big cloud in 3 seconds

Here's an example
This one was my previous coil it was homing too high so reduced the size and wraps I did push a needle between. That coil touching after the pic

 

[Kanj.nguyen]

For the best heat, you want to control 2 things: power and current.

So, let's take two different setups:

Setup A
1.5ohm coil
3.7v
Power = 9W
I = 2.46A

Setup B
3ohm coil
5.2v
Power = 9W
I = 1.7A

So, both setups are producing 9W of power in the form of heat, but the lower resistance coil has much more current going through it. More current means the wire heats up faster and that's why lower ohm coils have a hotter draw even though both are giving out the same Wattage. Since 28g wire has lower resistance per inch than 32g, this is why 28g produces vapor faster than 32g.

But that's basic stuff that you probably already know. The other main factors are surface area and air draw.

Surface area is pretty easy. The more coil you have in contact with the liquid, the more vapor you will get. This is why people wrap quad and octo coils: to increase the amount of coil in contact with liquid. Now, larger wire also has more surface area, but I don't believe the increase in surface area with the sizes we're using–like, say, the difference between 32g and 28g–will make a noticeable difference. The key is how many wraps you have total in contact with the wick/liquid.

But in addition to that you need air flow. (Note: the following is conjecture based on what I believe is happening. Please let me know if I've erred.) If the liquid vaporizes but is not drawn away quickly enough, the air around the coils can get saturated, leading to a pressure increase and raising the boiling point of the liquid in contact with the coils. More air holes will draw the vapor away from the coils more efficiently and end up producing more vapor.

Uh... Not sure about your math. If you use an appropriate gauge of wire in the low ohm coil so that it is still the same length of wire, just thicker, then the low ohm coil will actually heat up slower. Both have 9W dedicated to heating them up, but the low ohm coil has more mass (thicker, same length) to be heated up.

 

[sailense]

Uh... Not sure about your math. If you use an appropriate gauge of wire in the low ohm coil so that it is still the same length of wire, just thicker, then the low ohm coil will actually heat up slower. Both have 9W dedicated to heating them up, but the low ohm coil has more mass (thicker, same length) to be heated up.

While the low ohm coil has more mass, you have more current going through it, i.e. more electrons. 28g is about 0.3mm and 32g is about 0.2mm. I don't think that the extra 0.1mm of diameter is enough to make as much of a difference vs almost double the current.

In addition, there is also the temperature coefficient of resistance, so the resistance will decrease as the temperature increases. A low ohm coil resistance drop as temperature increases would be more pronounced.

But again, this is based on my experience and what little physics I know.

 

[JeremyR]

FYI the coil I pictured and described above was 30 gauge!

I got the wire from a friend he didn't know what it was I assumed 32.. When I ordered 32 I found it was absolutely 30! The 32 in same configuration was like 5 ohms... Not good- I need 30 or 28 now

 

[HDVaper]

Once you get good heat, you need more air flow. I actually opened up the air holes on my protank a little to get even more air. Getting huge clouds. If I crank the voltage and unscrew it to make it super airy u can get some huge clouds in 3 seconds. But you have to be carefull you don't go too big on the air flow because it will reduce flavor if you over do it.

I just made a really nice coil of 32, all I got, on protank. Used a round toothpick to wrap on. 6/7 wrap really close. Hold it tight . Made one twist of legs to hold tight glowed it on the stove pinched the coil tight quenched and repeated. It takes 3 mm silica, I space out the touching coils with a needle, just to the distance of the needle. Like a feeler gauge between the coils. It's 2.2 ohms. If I crank it to 15 watts and have the protank screwed out to get a lot of air. I get a really big cloud in 3 seconds

Here's an example
This one was my previous coil it was homing too high so reduced the size and wraps I did push a needle between. That coil touching after the pic

Is that THREE wicks wrapped together?

 

[JeremyR]

wow that post was kinda confusing..

actually that pic is - 4 1mm silica wicks, they sit stacked 2x2 in the channels. I use no overwick, you need light juice for this setup. 3 may be better for vg but I seemed to have problems with 3 leaking with my vg. I go 4 usually, Actually I run my protank unscrewed to get good wicking for chain vaping which is most the day.. I have since moved on to an oddy it rebuilds better, I was having problems with the rubber grommet burning and the flavor is gross.

Note the air bubbles that have come up it really make the flavor better on protanks, muting flavor is from slightly dry wicks.

 

[BigBen2k]

I'd start at 28 awg. The gauge does make a difference.

It's a fine art/science to wrap a wire around a wick; I'd focus on that. If you can make several, with perfect consistency, you'll be much better off.