Watts do not matter. Its all about wire temp. Read on

[gdeal]

I still believe the starting point should be wire temp. Wire temp is what is needed for ejuice to reach its vaporization point. The other factors coalesce around it; air flow, wick heat sink and ejuice flow/cooling. Change those factors and you need to changed power levels to maintain an optimal state.

An issue with thinner wires (and the inherent larger thermal gradiant, ie: the wire heat is more concentrated) is that there is a greater chance of "dry wick". Capillary action of a wick will significantly diminish if the capillaries empty. Filled capillaries will transport fluid much faster, then ones being emptied by vaporization.

The variability of thermal zones are lower with thicker wires, thus the potential for dry wick is reduced. If you reduce the potential for dry wick, you can increase airflow for greater evaporation. If you increase the potential for greater air flow, and have minimize the potential for dry wick, you can increase the power to the coil to meet the potential of ejuice flow/capillary action of the wick. Do all that and you have the optimal vape.

Of course this is easier said than actually done....

Thicker wire = more potential vapor.

 

[jasl90]

I still believe the starting point should be wire temp. Wire temp is what is needed for ejuice to reach its vaporization point. The other factors coalesce around it; air flow, wick heat sink and ejuice flow/cooling. Change those factors and you need to changed power levels to maintain an optimal state.

An issue with thinner wires (and the inherent larger thermal gradiant, ie: the wire heat is more concentrated) is that there is a greater chance of "dry wick". Capillary action of a wick will significantly diminish if the capillaries empty. Filled capillaries will transport fluid much faster, then ones being emptied by vaporization.

The variability of thermal zones are lower with thicker wires, thus the potential for dry wick is reduced. If you reduce the potential for dry wick, you can increase airflow for greater evaporation. If you increase the potential for greater air flow, and have minimize the potential for dry wick, you can increase the power to the coil to meet the potential of ejuice flow/capillary action of the wick. Do all that and you have the optimal vape.

Of course this is easier said than actually done....

Thicker wire = more potential vapor.

I absolutely agree that wire temp is the correct starting point. I think it's also important to have a firm understanding of the variables that are involved. People seem get so focused volts, watts and resistance that they ignore the significance of wire gauge. When I first started wrapping coils, I was puzzled by the fact that I could wrap a 1.7 ohm coil that metered out to the exact same resistance as my 1.7 ohm Cisco 306's, but the vape was completely different. I could slap a 306 on an ego battery and get a great vape. When I replaced it with my RBA, it was nowhere near as good.
So... I decided to rip open a couple 306's and see what the hell was going on.
I found three things...
1) The coils where were small in diameter
2) The coil spacing was very compact... Touching as a matter of fact.
3) The wire was much thinner than what I was using.

It was those three elements (the wire diameter being the most important of the three) that made the drastic difference between my old coils and the 306... At least in terms of the wire temp...

 

[cckk]

• More coil on wick = better
• More consistent/lower coil temp = better
• 28g coil for coil/watt for watt better than 32g

1) The coils where were small in diameter
2) The coil spacing was very compact... Touching as a matter of fact.
3) The wire was much thinner than what I was using.

I’m very glad that you both agree one with the other but it seems that we have now two conceptions:

gdeal: better taste is produced by large coil made of thicker wire

jasl90: better taste is produced by compact coil made of thinner wire

So both these hypothesis are right? Because that leads to the conclusion: each coil is the same.

 

[Mad Scientist]

I still hesitate driving any stakes in the ground as yet. I fully agree that wire temp is a very important indicator to determine performance of an atomizer, but I'm not yet ready to agree that it's a starting point. Maybe power considered with wire temp tell us heat transfer efficiency from which we can infer surface area, wick reservoir, and over a set time, wicking (assuming a constant airflow). See what I mean?

 

[gdeal]

cckk, I sort of agree with you. The closer coils are, the less the thermal gradient will be. So Jas90 and I are talking about the same thing. If the wires are touching, you can effectively minimize the thermal gradient by adjusting power.

I really was trying to stay away from taste, because its so subjective. Some ejuice, like tobacco flavor work well/better with greater thermal gradients. Other flavors, like peppermint, are better with consistent thermal gradients. I wouldnt say that the coils are the same. Thicker wire (less resistance) will permit great surface area for vaporization, but you need to be able to supply the power to get the right vape temp quickly.

So you can possibly achieve equal types of thermal gradients with a thin wire and thick wire. But the thicker wire will always provide a denser vape and a denser vape is always more concentrated with flavor.

 

[Mad Scientist]

I’m very glad that you both agree one with the other but it seems that we have now two conceptions:

gdeal: better taste is produced by large coil made of thicker wire

jasl90: better taste is produced by compact coil made of thinner wire

So both these hypothesis are right? Because that leads to the conclusion: each coil is the same.

Ureka (maybe lol). It may also lead to the conclusion that the characteristics of each that are similar are what drive better performance. I can hypothesize exactly what those are but I'm tired at the moment lol.

 

[jasl90]

Not really... "Better" a subjective term. It's all about what you like as in individual. Understanding the base principals simply allows you to achieve what's best for you... and the device you're using it on.

As an example... On my mechs, I've found that I like to be around 0.75 ohms with 28 awg kanthal and 0.9 ohms with 30 awg wire.
With my Provari, I like 1.35 to 1.5 ohms with 30 awg wire and 1.5 to 1.8 ohms with 32 wag wire... I never use wire thicker than 30 awg on a Provari build.

Yes, I have good reasons for using those specific sets of values but I don't expect anyone to blindly follow the... Simply because they are the values that tend to give me the vape that I like with the attys and juices that I use.

In addition, there are other variables that can come into play which my force your hand one direction or another... Wick diameter, distance between terminals and the amount of physical space in the coil area, can all impose constraints. A good understanding of the base principals allows you to make informed (or at least good, educated guesses) when deciding what coil to put on a given atty.

 

[gdeal]

I still hesitate driving any stakes in the ground as yet. I fully agree that wire temp is a very important indicator to determine performance of an atomizer, but I'm not yet ready to agree that it's a starting point. Maybe power considered with wire temp tell us heat transfer efficiency from which we can infer surface area, wick reservoir, and over a set time, wicking (assuming a constant airflow). See what I mean?

I see where you are going...but....I start with wire temp, because all the other driving factors are really variable by the user. Yes, you could change from Kanthal to Nichrome, wick materials etc, but vaporization points of PG/VG are fixed. You could play with the vaporization point with PG/VG mix %, diluting with water, PGA, etc. but that will change the vapor/flavored produced. So I assume the constant is the ejuice that you buy (or make) and prefer to vape and then change the other variables around that to optimize vapor production regardless of heating element, wick material etc.

 

[Mad Scientist]

Not really... "Better" a subjective term. It's all about what you like as in individual. Understanding the base principals simply allows you to achieve what's best for you... and the device you're using it on.

As an example... On my mechs, I've found that I like to be around 0.75 ohms with 28 awg kanthal and 0.9 ohms with 30 awg wire.
With my Provari, I like 1.35 to 1.5 ohms with 30 awg wire and 1.5 to 1.8 ohms with 32 wag wire... I never use wire thicker than 30 awg on a Provari build.

Yes, I have good reasons for using those specific sets of values but I don't expect anyone to blindly follow the... Simply because they are the values that tend to give me the vape that I like with the attys and juices that I use.

In addition, there are other variables that can come into play which my force your hand one direction or another... Wick diameter, distance between terminals and the amount of physical space in the coil area, can all impose constraints. A good understanding of the base principals allows you to make informed (or at least good, educated guesses) when deciding what coil to put on a given atty.

What if you were designing an atty and had no constraints? Many (most?) present atty designs are horrible compromises to now obsolete power sources and homages to minimized manufacturing costs.

Your initial question is the hardest to answer: what is better? I know what I'm trying to accomplish and can only hope it's worthwhile lol.

 

[jasl90]

Actually I do make my own attys...

 

[dr g]

I still hesitate driving any stakes in the ground as yet. I fully agree that wire temp is a very important indicator to determine performance of an atomizer, but I'm not yet ready to agree that it's a starting point. Maybe power considered with wire temp tell us heat transfer efficiency from which we can infer surface area, wick reservoir, and over a set time, wicking (assuming a constant airflow). See what I mean?

You do have a good ongoing point here about the phase change issue vis a vis thermal transfer, you are right that the juice and its phase change is going to, to a certain extent, stabilize the temperature of the coil. So what jasl90 said earlier is sort of too simplistic along the lines of the original example I gave in the other thread. It is an explainer of general wire behavior but you are right that actual atomizer performance is heavily affected by the fact of the presence of juice and the (imperfect) thermal coupling between it and the coil.

We can't have one thickness of wire literally heating up too far beyond that of another, the liquid vaporizes at a certain temperature and everything we do serves to create an area at that temperature. There is a range in which the temperature creates an acceptable vape surely, and the overall amount of heat energy being radiated affects things in other ways, for example, big coils tend to heat up the atomizer body as well which I believe contributes to warming the vapor as well, whereas thin coils localize the heat much more and heat up atomizer bodies a lot less.

 

[cckk]

Maybe power considered with wire temp tell us heat transfer efficiency from which we can infer surface area, wick reservoir, and over a set time, wicking (assuming a constant airflow). See what I mean?

In addition, there are other variables that can come into play which my force your hand one direction or another... Wick diameter, distance between terminals and the amount of physical space in the coil area, can all impose constraints. A good understanding of the base principals allows you to make informed (or at least good, educated guesses) when deciding what coil to put on a given atty.

The physics isn’t the theory which tells us: the world is so complicated that we could discuss each effect infinitely... and we will.

The physics is the theory which tells us: in the case of that effect these few factors play the main role and the other ones are significantly less essential.

That feature of the physics allows us to formulate the laws which include very often just three variables – such as Ohm’s law – rather than 1000 of the variables.

We’re now after post #170 and it seems that we’re still at the beginning. (dr g, you’re right: I clogged that thread with a few posts about VAMO so let’s assume that we’re now after #160 post and still at the beginning.)

***

Not really... "Better" a subjective term. It's all about what you like as in individual.

So is there some common ground for the discussion or everyone is the other and everyone likes something other and – as a result – we are the separated universes which can’t communicate sensibly one to the other?

I hear or read that “truth” at least once a day. Its worse variant is: everyone has the right to have (and express) his or her own opinions on everything. I agree. Everyone can think, talk, and write anything but that doesn’t mean that anything is enough the same wise, good, fine, etc. as everything else.

 

[Mad Scientist]

... So is there some common ground for the discussion or everyone is the other and everyone likes something other and – as a result – we are the separated universes which can’t communicate sensibly one to the other?

I hear or read that “truth” at least once a day. Its worse variant is: everyone has the right to have (and express) his or her own opinions on everything. I agree. Everyone can think, talk, and write anything but that doesn’t mean that anything is enough wise, good, fine, etc. as everything else.

I'm right there with you. Without objective characteristics that can be measured, it can become a pointless exercise. All we need to agree on are which characteristics are relevant lol. From where I sit, "more" of fully saturated vapor is better. If a user wants less of either, that's easy to deliver either by reducing power or by taking shorter hits. I've found that for a very quick and dirty comparison of design changes, a design's ability to handle more power is the better one. Your approach with wire temp is an even better measure in many respects, depending on what variable is changed. For fine tuning though, even that doesn't give enough info, I don't think.

 

[jasl90]

I think that there is a huge amount of common ground. The real problem that we face, is the fact that we don't have any way of attaching hard numbers to the actual wire temp or the response times.
We can certainly see the difference... On one coil, you may see the entire coil glow red hot almost instantly. On a 2nd coil you may see it start to glow more gradually, starting at the center of the coil, working its way out.

We know by simple observation, that the 1st coils is getting hotter and getting up to temperature faster than the 2nd coil...
Unfortunately, we have no means of saying, "coil #1 hit X degrees in 0.X seconds and coil #2 hit Y degrees in 0.Y seconds".
In the absence of hard numbers, we are only left with the option of talking about the variables. Considering the shear number of variables that come into play, we need to, at least in theory, hold a some variables constant, so that we can discuss the few that are immediately relevant.

So... Yes... I can say (with all other variables held constant) that thinner wire gets hotter and gets there faster than thicker wire. How much hotter??? How much faster??? Beats me... I've got no way to accurately attach numbers to it.

Fortunately, we don't need the numbers. The whole point of all of this is to find a vape that we, as individuals, enjoy. If you take a puff and think, "this is too hot and my juice tastes like burnt ..." or "this too cool and the vapor feels soggy" then you need to know what adjustments to make on the next coil.
Please note that I'm am not advocating for thin wire, nor am I saying that a warm vape is better than a cool vape or vise versa. That, I believe, is purely a personal preference.

 

[cckk]

All we need to agree on are which characteristics are relevant lol.

That’s the point (except the “lol” thing).

 

[dr g]

I think that there is a huge amount of common ground. The real problem that we face, is the fact that we don't have any way of attaching hard numbers to the actual wire temp or the response times.
We can certainly see the difference... On one coil, you may see the entire coil glow red hot almost instantly. On a 2nd coil you may see it start to glow more gradually, starting at the center of the coil, working its way out.

We know by simple observation, that the 1st coils is getting hotter and getting up to temperature faster than the 2nd coil...
Unfortunately, we have no means of saying, "coil #1 hit X degrees in 0.X seconds and coil #2 hit Y degrees in 0.Y seconds".
In the absence of hard numbers, we are only left with the option of talking about the variables. Considering the shear number of variables that come into play, we need to, at least in theory, hold a some variables constant, so that we can discuss the few that are immediately relevant.

So... Yes... I can say (with all other variables held constant) that thinner wire gets hotter and gets there faster than thicker wire. How much hotter??? How much faster??? Beats me... I've got no way to accurately attach numbers to it.

Fortunately, we don't need the numbers. The whole point of all of this is to find a vape that we, as individuals, enjoy. If you take a puff and think, "this is too hot and my juice tastes like burnt ..." or "this too cool and the vapor feels soggy" then you need to know what adjustments to make on the next coil.
Please note that I'm am not advocating for thin wire, nor am I saying that a warm vape is better than a cool vape or vise versa. That, I believe, is purely a personal preference.

It's probably worth mentioning that as far as I know, during actual operation, the coil should not reach glow temperature.

 

[jasl90]

You are correct. Coils should not glow when wet. The liquid does provide a substantial heat sync. That however does not mean that the amount of heat energy by the coil is any less... The reason wet coils glow is because the heat energy is transferred to the juice, which in turn, causes it to vaporize. The more heat energy a coil produces, the more heat energy it can impart to the wick and juice. Too much heat and you'll get a burnt taste from your juice and dry hits... Too little heat and you get reduced vapor and, what I'd describe as cold & soggy' hits.

 

[cckk]

I just finished to watch “The Conjuring” by James Wan. It seems that chasing the ghosts is a relatively very easy task in the comparison to trying to determine what happens in the device built from the battery, coil, and wick which uses as a medium the liquid.

The exorcisms are exactly as dangerous as using a mechanical MOD with genesis RBA atomizer at 0.1 Ω with four stacked 18650 unprotected batteries. You need just “Holy Bible”, the cross, holy water, and a bit of sentiments.

Maybe I should become an exorcist instead of the vaper to make my life more simple?

 

[jasl90]

Add holy water to your juice...

 

[dr g]

You are correct. Coils should not glow when wet. The liquid does provide a substantial heat sync. That however does not mean that the amount of heat energy by the coil is any less... The reason wet coils glow is because the heat energy is transferred to the juice, which in turn, causes it to vaporize. The more heat energy a coil produces, the more heat energy it can impart to the wick and juice. Too much heat and you'll get a burnt taste from your juice and dry hits... Too little heat and you get reduced vapor and, what I'd describe as cold & soggy' hits.

Yup, however if you were to look at a temperature curve of a coil, it most likely would show a plateau around the boiling point of VG or PG. This is a point mad scientist had in another thread and it is likely true. Technically if operating correctly our coils should fall within a similar range of temperatures when vaping.