Dry hits and burned coils in TC mode no matter what when vaping high VG, how can I fix this?

unixunderground · Feb 23, 2017

Hey guys,

I've recently gotten a new TC mod that supports SS316L coils in TC mode, as I've had enough of dry hits and burned coils in wattage mode. (Innokin CFIV 18650 TC)

The issue is that I don't like throat-hit and therefore PG, and also enjoy clouds.
As such I am always leaning towards high VG juices (ideally I think I'd enjoy vaping 100% VG). In wattage mode this led me to experience constantly burned coils and dry hits as the cotton isn't able to wick up the thick VG juice fast enough.

I thought getting a TC mod would fix this, however after a week of usage, this doesn't seem to be the case.

I am using an 80/20 VG/PG liquid, on an iSub tank with a 0.5ohm 316L coil.
This coil is rated for up to 60W and 245 C/474 F in TC mode.

I've set my mod at 60W max heating wattage, and at a temperature of 210 C / 410 F.

After a week of usage I noticed I started getting a funky taste and a much tighter draw.
Today I inspected the coil and after removing the metal mesh I found all the cotton inside it completely blackened and burned up.

Why did this happen and I can I solve it? Is the coil/tank I am using unsuitable for high VG?

Would getting an RTA prevent dry hits? Perhaps even with 100% VG?

Any input on this is appreciated.

Eskie · Feb 23, 2017

Is the issue you're getting dry hits in TC mode, or you changed to TC to avoid dry hits? Also, just because a coil is "rated" to 60W doesn't mean that's what to use, for either wattage or TC mode. I run 0.25 ohm dual coils with a 40W 450F and other than my preheat setting for the first second, it's rarely at 40W, so that can be turned down.

As to the black yucky coil after a week, well that's what happens to them, wattage or TC mode. It's dependent on the juice you use (more sweeteners more gunking) and how much juice you vape through the coil (the more you vape per day the sooner a coil will gunk).

Using an RTA does give you an advantage in that when the cotton is all dirty, you can remove it, clean the coil wire, and rewick. There are different ways to clean the coil which typically includes a little dry burning to get surface residue off. The only guarantee against a dry hit is good wicking which is easier to achieve in an RTA you build yourself. Well, that and working TC.

Rossum · Feb 23, 2017

How much flavoring & sweetener is in your juice? Are you sure the cotton is burnt and not just gunked up with residue that didn't vaporize? Some juices will gunk up a coil and wick in a day, others may let you run several weeks.

unixunderground · Feb 23, 2017

Eskie said:
Is the issue you're getting dry hits in TC mode, or you changed to TC to avoid dry hits? Also, just because a coil is "rated" to 60W doesn't mean that's what to use, for either wattage or TC mode. I run 0.25 ohm dual coils with a 40W 450F and other than my preheat setting for the first second, it's rarely at 40W, so that can be turned down.

As to the black yucky coil after a week, well that's what happens to them, wattage or TC mode. It's dependent on the juice you use (more sweeteners more gunking) and how much juice you vape through the coil (the more you vape per day the sooner a coil will gunk).

Using an RTA does give you an advantage in that when the cotton is all dirty, you can remove it, clean the coil wire, and rewick. There are different ways to clean the coil which typically includes a little dry burning to get surface residue off. The only guarantee against a dry hit is good wicking which is easier to achieve in an RTA you build yourself. Well, that and working TC.

I changed to TC to avoid dry hits, but inspecting my coil after TC usage it too seems to have been badly burned up.

Thanks, good point, I'll try lowering it to 40-50W. Though looking at the display it usually is at peak set wattage for just a fraction of a second and then quickly goes to lower wattages to keep the set temperature.

Great, I'll start looking into getting an RTA. Any recommendations on a good RTA? Perhaps one with wick holes large enough for it to be able to wick 100% VG properly (if that exists?)
I've looked at the Merlin Mini (Augvape) and the iJoy eXo. Are these any good?

I am also under the impression that RTAs are much larger than standard sub-ohm tanks, is this right? Not sure if one of these would fit on my CF IV 18650.

unixunderground · Feb 23, 2017

Rossum said:
How much flavoring & sweetener is in your juice? Are you sure the cotton is burnt and not just gunked up with residue that didn't vaporize? Some juices will gunk up a coil and wick in a day, others may let you run several weeks.

Not sure about quantities, I am using a watermelon/kiwi one right now (no colouring), though if to a lesser extent I remember this happening when vaping pure unflavored 80/20 VG too.

It's a bit hard to see but it definitely seems burned to me. Here are some pics, what do you think?
Imgur: The most awesome images on the Internet
Imgur: The most awesome images on the Internet
Imgur: The most awesome images on the Internet

r77r7r · Feb 23, 2017

So, it's possible to get dry hits and burnt hits with TC? I thought it was all about preventing that from occurring in the first place?

Eskie · Feb 23, 2017

unixunderground said:
I changed to TC to avoid dry hits, but inspecting my coil after TC usage it too seems to have been badly burned up.

Thanks, good point, I'll try lowering it to 40-50W. Though looking at the display it usually is at peak set wattage for just a fraction of a second and then quickly goes to lower wattages to keep the set temperature.

Great, I'll start looking into getting an RTA. Any recommendations on a good RTA? Perhaps one with wick holes large enough for it to be able to wick 100% VG properly (if that exists?)
I've looked at the Merlin Mini (Augvape) and the iJoy eXo. Are these any good?

I am also under the impression that RTAs are much larger than standard sub-ohm tanks, is this right? Not sure if one of these would fit on my CF IV 18650.

I have a CF4 18650. It will take a 25 mm tank without any overhang. Choices in RTAs is extensive. Do you want to keep up with a midrange power setup for flavor or flat out want clouds? Have you any experience building vape stuff?

r77r7r said:
So, it's possible to get dry hits and burnt hits with TC? I thought it was all about preventing that from occurring in the first place?

TC is to prevent dry hits. The OP changed to it as they were getting dry hits in watt mode. The dirt gunky coil after a week of use is just that, a dirty gunky coil. Not burnt, just dirty, or the taste would have been, well, dry hit hell for the entire week of use.

Eskie · Feb 23, 2017

unixunderground said:
Not sure about quantities, I am using a watermelon/kiwi one right now (no colouring), though if to a lesser extent I remember this happening when vaping pure unflavored 80/20 VG too.

It's a bit hard to see but it definitely seems burned to me. Here are some pics, what do you think?
Imgur: The most awesome images on the Internet
Imgur: The most awesome images on the Internet
Imgur: The most awesome images on the Internet

Honestly it just looks gunky and dirty. If a coil is actually burnt, every draw off it you made would have tasted burned and sorta like a dry hit. If the vape tasted OK until you pulled that coil it wasn't burned. There are photos around here of people showing wicks/coils that were, for want of a better word, disgusting, but they swore it still tasted OK, they were just upset at the appearance.

unixunderground · Feb 23, 2017

Eskie said:
I have a CF4 18650. It will take a 25 mm tank without any overhang. Choices in RTAs is extensive. Do you want to keep up with a midrange power setup for flavor or flat out want clouds? Have you any experience building vape stuff?

Great to hear. Not too sure, this would be my first RTA. I'd like proper clouds and good flavor when using flavored juices (though I rarely do).

I don't really fancy hot vapor, so I'd most likely be running it in TC mode with a 316L wire most of the time. Also great if it can fit the CF4, I am very much enjoying its small size.

Most important to me would be having proper wicking holes, preferably large enough to allow for 100% VG vaping, easy refilling and also good seals/design making it unlikely to suffer from leakage.
Also it'd be good if it wasn't too tall as I enjoy a pocketable format.

Is there any good RTA fitting this description that you'd recommend?

I don't have any experience with building vape stuff, though I do have some electronics/soldering experience and from watching youtube videos it looks very easy to put in a pre-coiled wire, testing the resistance, pinching it and adding some cotton. Is there anything in particular I should be aware of?

Eskie · Feb 23, 2017

unixunderground said:
I don't have any experience with building vape stuff, though I do have some electronics/soldering experience and from watching youtube videos it looks very easy to put in a pre-coiled wire, testing the resistance, pinching it and adding some cotton. Is there anything in particular I should be aware of?

It's the pinching and adding some cotton part that will get you when you first start. Wrapping and mounting a coil is flat out easy. Wicking is where the art is.

I'm loving my OBS Engines right now. Top fill, top air, no leak. Major plus. I think they perform very well with excellent flavor and good cloud, but there are better cloud tanks out there. The Crius+ from the same company is also a nice choice with lots of airflow for clouds, but I still get good flavor. Other standard recommendation for a higher power cloud tank would include a Boreas (not my fave but there are lots of folks who swear by them) or an Aromamizer with a few to choose from including a 25 mm version (and a 30 mm version if you want a flat out giant tank, it will still fit the CF4, but with significant overhang). Another thought is an RDTA like a Limitless+, or even the RTA Limitless models now being released.

Understand as you get into bigger tanks with bigger coils you power demands go up. While a CF4 can get you a very good vape, it's not going to supply very high current and certainly the battery will run down quickly. It's the trade off of small size with a single battery, or a larger, bulkier multi-battery mod. There are some 2 battery mods like the Alien that are still very manageable to carry in your pocket.

zoiDman · Feb 23, 2017

Dry hits and burned coils in TC mode no matter what when vaping high VG, how can I fix this?

Have you tried Adding a few drops of Water to your High VG e-Liquids?

Might do a Test by adding a couple of Drops of Water to your Tank and the fill it with you e-Liquid.

daviedog · Feb 23, 2017

Zoid trumped my ace.
You also have to be diligent in keeping your wicks moist in hi-viscosity juice. Let gravity work for you.
Don't rely on a chip to do all the work.
An RTA, and hand made coil Is the way to go..

SteveS45 · Feb 23, 2017

I use High or Max VG e-Liquids and have never had a burnt hit in TC Mode using SS316L even chain vaping. But I am thinking that your tank is vapor locking and the e-Liquid is not saturating the coil. A suggestion is to maybe try loosening the top cap on your tank after a few pulls and look if you see bubble from the coil. I am not familiar with your tank so this is just me thinking out loud! Good Luck!

unixunderground · Feb 26, 2017

Eskie said:
It's the pinching and adding some cotton part that will get you when you first start. Wrapping and mounting a coil is flat out easy. Wicking is where the art is.

I'm loving my OBS Engines right now. Top fill, top air, no leak. Major plus. I think they perform very well with excellent flavor and good cloud, but there are better cloud tanks out there. The Crius+ from the same company is also a nice choice with lots of airflow for clouds, but I still get good flavor. Other standard recommendation for a higher power cloud tank would include a Boreas (not my fave but there are lots of folks who swear by them) or an Aromamizer with a few to choose from including a 25 mm version (and a 30 mm version if you want a flat out giant tank, it will still fit the CF4, but with significant overhang). Another thought is an RDTA like a Limitless+, or even the RTA Limitless models now being released.

Understand as you get into bigger tanks with bigger coils you power demands go up. While a CF4 can get you a very good vape, it's not going to supply very high current and certainly the battery will run down quickly. It's the trade off of small size with a single battery, or a larger, bulkier multi-battery mod. There are some 2 battery mods like the Alien that are still very manageable to carry in your pocket.

daviedog said:
Zoid trumped my ace.
You also have to be diligent in keeping your wicks moist in hi-viscosity juice. Let gravity work for you.
Don't rely on a chip to do all the work.
An RTA, and hand made coil Is the way to go..

Thanks guys. I bit the bullet and gave up on pre-made atomizer tanks. As convenient as they are they have never wicked properly for me.

Actually though I initially wasn't very inclined after researching it I am quite liking the thought of having just bought enough cotton and wires to last for years.

Just ordered an OBS Engine Nano, Avocado 24 and a Geekvape Medusa as well as a new 200W TC mod to handle higher power builds/get better battery life.

zoiDman said:
Dry hits and burned coils in TC mode no matter what when vaping high VG, how can I fix this?

Have you tried Adding a few drops of Water to your High VG e-Liquids?

Might do a Test by adding a couple of Drops of Water to your Tank and the fill it with you e-Liquid.

SteveS45 said:
I use High or Max VG e-Liquids and have never had a burnt hit in TC Mode using SS316L even chain vaping. But I am thinking that your tank is vapor locking and the e-Liquid is not saturating the coil. A suggestion is to maybe try loosening the top cap on your tank after a few pulls and look if you see bubble from the coil. I am not familiar with your tank so this is just me thinking out loud! Good Luck!

Thanks! I'll try out adding a few drops of water. This could be a good fix for my e-liquids being too think. As I am using pure pharmaceutical grade glycerol without water and I can see many pre-made juices using "aqueous VG".

Vapor locking also seems quite likely, the way this tank it's made it's completely sealed all over (no top cap) and no air at all gets in other than through the coil. Looking forward to my RBA tanks and drippers, they should hopefully help!

Dry hits and burned coils in TC mode no matter what when vaping high VG, how can I fix this?

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