burning and/or bown discoloration of wick against coil

[P-Funk]

I have been building my own atomizers for a few years now, on and off. Recently (within the last six months) I started using rta style devices exclusively, so I have built and wicked quite a few.

Rayon has become my goto material for wicking, as for me it seems to last longer and generally give fewer problems than cotton does. I use the 100ft Sally Beauty ropes that can be found cheaply on Amazon.

Yesterday I first built on a new rta, the VandyVape Berserker, and I have so far tried two very different styles of build in it:

• a standard tootle build: 10 wrap 26 gauge kanthal, 2.5mm inner diameter, 1.2ohm, fired at 15 watts
• my kinda tootle build: 5 wrap dual-strand twisted 28 gauge kanthal, 2.0mm inner diameter, .35ohm, fired at 12 watts

With both builds, within minutes, there is some brown discoloration evident in the wick around where it contacts the coil, along with a telltale slight burning flavor. What causes this?

I am fairly certain my wicks are wicking well enough. I have been using rayon for a while now so I know the tricks: wick it tight through the coil, thin the wick ends, etc. I have constructed rayon wicks in my Innokin Ares that have lasted for up to two weeks without issue until the coil gets too gunked up, so I know it is possible to do and that I have the skill to do it properly.

Also possibly pertinent: I mix my own juice, 70/30 PG/VG, citrus and menthol flavors, no sweeteners. My juices are thin and they normally burn pretty clean, taking a long time to gunk up my coils.

I was wondering if there are other factors that might cause this. Airflow, perhaps? A certain kind of build defect?

Has anyone else had this issue in any of their devices? Were you able to identify and correct the problem?

As always, thanks for your ideas and info!

 

[Falconeer]

Two long shots...

1) Could your juice be too thin for that wick material? Would 50/50 wick or saturate the wick quicker or for longer?

2) Again for that particular material could you be using too much power? Personally for 1.2 ohm coil, me being a tootle puffer, would run that one at 8 -10 watts.

As I said just a couple of long shot thoughts; others will probably have better ideas.

 

[CagedSpam]

brown discoloration evident in the wick around where it contacts the coil, along with a telltale slight burning flavor. What causes this?

It is my understanding the brown stuff is unvaporized flavoring. After getting the burning flavor, what did the wicks looks like after pulling them? Spaced or contact coils?

Even minor discoloration/scorching would lead me to believe a wicking issue. Maybe related to coil I.D. size, tails too thin, or some other variable.

GL!

 

[P-Funk]

Two long shots...

1) Could your juice be too thin for that wick material? Would 50/50 wick or saturate the wick quicker or for longer?

2) Again for that particular material could you be using too much power? Personally for 1.2 ohm coil, me being a tootle puffer, would run that one at 8 -10 watts.

As I said just a couple of long shot thoughts; others will probably have better ideas.

As for (1), I have been using my own mix of 70/30 : PG/VG for a long time now and I have never had issues with it.

As for (2), you might be right about firing too hot on that first build. Logically, if I am firing a .35ohm coil at 12 watts I should be firing a 1.2ohm coil at less than 12 watts, right?

But, both builds produced singed wicks. As I sit here vaping on the second build (still using the singed wick) the burnt flavor has worked itself out and I think the build may have stabilized into something usable.

Still curious if people have experience with rayon wicks and initial singing issues.

 

[P-Funk]

It is my understanding the brown stuff is unvaporized flavoring. After getting the burning flavor, what did the wicks looks like after pulling them? Spaced or contact coils?

Even minor discoloration/scorching would lead me to believe a wicking issue. Maybe related to coil I.D. size, tails too thin, or some other variable.

GL!

My coils are not spaced. I squeeze the coils shut with ceramic forceps after burning them red-hot to make sure they are contacting evenly.

The first wick, when I pulled it, was black all along the inner diameter of the coil. The black didn't rinse out under the faucet, either. It was for sure burnt to a crisp.

Falconeer suggested maybe I was firing at excessive power. He might be right about that.

Thanks for the thoughts!

 

[Mordacai]

P-Funk, could you have the rayon a little bit too tight through the coil? As this would prevent the liquid wicking efficiency, so it could dry out and then end up getting toasted.

 

[IDJoel]

Still curious if people have experience with rayon wicks and initial singing issues.

Hi @P-Funk,

I would start by looking at what you are using for rayon. Graham Beauty (the manufacturer of CelluCotton Beauty Coils) makes rayon, rayon reinforced, cotton, and cotton reinforced versions of their beauty coils... all under the same CelluCotton label. What is the specific part number of the product you are using?

If you are using the 10ft. bag (I couldn't find a 100ft. package; either on Graham, or Amazon) with the part #44145; that is cotton, and not rayon. Graham does not offer a 10ft. package of rayon. If it is re-packaged; all bets are off.

I ask this, because rayon is much harder to scorch than cotton... at least at safe vaping temperatures, and any presence of moisture.

I too vape the Berserker (24mm v1) using rayon (CelluCotton #44060). Only I use stainless steel instead of kanthal (for temp control). One of the very reasons I use rayon; is for its heat resistance. I seem to chronically empty a tank to the point of taking a dry hit. Put it down. Pick it back up without thinking or looking and take another dry hit. then, repeat two or three more times, until I finally refill my tank. I am the poster child for absentmindedness. I have never had a scorched rayon wick (not even discolored); even with multiple dry hits. Cotton, on the other hand, is an entirely different story. As I remember, I was burning a wick, at least once a week.

I also agree with @Falconeer, that 8 watts seems to be a nice sweet spot for a 1.2Ω coil in the Berserker. I must say; I never thought about using 26ga. though. I just now had to wrap one, and hold it up to the build deck, just to see if it would even fit. That is one tight squeeze. It also must be one HOT vape in such a small tank with tight airflow.

I would try the following:
1. Check that you truly have rayon.
2. Lower the wattage.
3. Try using slightly less material when wicking. Rayon is used more densely packed than cotton. But, it is still possible to use too much. When I first started using rayon, I was intimidated by all the posts advising, to pack it tighter. As a result; I was forcing it in so tightly, that I was just shy of majorly distorting my coil(s). It worked, but the resulting vape was less than impressive.

Then, I tried using a little less, but still more than I would when using cotton. The resulting vape was much better.

The one other trick (if you can call it a "trick") I found helpful, when it comes time to wick; is washing my hands with soap and water immediately before wicking (rayon or cotton). My hands always seem to get a thin film of vape "stuff" on them, as I am rebuilding (handling wire, tools, and miss. vape hardware). As I size, shape, fluff, and roll my wicks; I am transferring that stuff onto the wicking material. Which resulted in poorer wicking action, shorter wick life, and reduced or off tastes to the vapor.

By simply washing my hands; all those issues went away. This may seem like a no-brainer to most people, but to me, it was an "ah-ha!" moment.

Something I read in one of the rayon threads said it is not at all uncommon to see a darkening (browning?) begin to occur on the wick, from the ends of the coils, and grow (over time) outward away from the coil. I think(?) this was attributed to the capillary action of the rayon. Fluid flows toward the coil during vaping. And, then away again, as the wick re-attains saturation. This back-and-forth action slowly draws the normal vaping residue (a.k.a. "gunk") down the wicks. As I understand it, this is normal, and should not be confused with burning. Of course, different e-liquid contents (recipes) will make this more apparent in some vs. others.

 

[Frenchfry1942]

I get some browning under the coil. I will loosen my rayon and see if it reduces.

I do DIY and lean to sweeter flavors. Not sure if that is pertinent.

Am running 70/30 PG at 1.1 and 10-11 watts. That should put me at about 3.8 volts.

 

[P-Funk]

Hi @P-Funk,

I would start by looking at what you are using for rayon. Graham Beauty (the manufacturer of CelluCotton Beauty Coils) makes rayon, rayon reinforced, cotton, and cotton reinforced versions of their beauty coils... all under the same CelluCotton label. What is the specific part number of the product you are using?

If you are using the 10ft. bag (I couldn't find a 100ft. package; either on Graham, or Amazon) with the part #44145; that is cotton, and not rayon. Graham does not offer a 10ft. package of rayon. If it is re-packaged; all bets are off.

The wick material I am using is actually Graham Beauty CelluCotton 100% Rayon #44130. It is a 40ft box, not 100ft. I must have confused 100% with 100ft. And Sally Beauty with Graham Beauty. I should pay more attention when I try to provide background information! Pretty sure it IS actually rayon, as I have had much better luck with it than I have with cotton.

For now, I have settled on using the second build I posted above: 5 wrap dual-strand twisted 28 gauge kanthal, 2.0mm inner diameter, .35ohm, fired at 12 watts. It is large for the deck, barely fits in there, but it does fit. Vapor production is very nice and the vapor is cool and tasty! Only issue is the singe factor, which hopefully will be remedied shortly.

I am going to rewick with a bit less Rayon as it really is in there quite tight. The twisted kanthal coil is nearly impossible to distort as the twisted wires are extremely stiff, so coil distortion tendency probably isn't a great measure for me when it comes to rayon tightness.

As a final musing, I wonder what it is about the Berserker or the coil builds I put in it yesterday that is causing this issue... I have been using rayon in the Ares for about 5 months with more than a dozen successful builds, no burnt wicks. Guess I'll chalk it up to growing pains and take my lumps on the chin.

Will report back. Thanks again for the suggestions!

 

[stols001]

Could be a few things. Airflow is low in the Berserker, period. So, you may have to take that into account in the Berserker.

Too tight in the coil with rayon will cause early discoloration then the wick breaks in half with the coil. You may have too much wick.

The doggy style is particularly bad about staining wick, it's kind of a known issue. Raising the coil off the deck some seems to help with that.

Good luck,

Anna

 

[DaveP]

Rayon shrinks when wet with juice, so wicking a little tighter at first is better. It should puff up on both sides of the coil when you first insert the wick. You should be able to move it back and forth without bending the legs on a 28ga coil, but there should be some resistance to movement.

My rayon wicks always look a little brown when I pull the atomizer apart to rewick, but after I wash the wick in water and re-inspect it the wick is clean except for a grey stain from contact with the SS316 coil. The brown color is from caramelized juice.

If there's a burnt flavor my guess is that the wick isn't tight enough and it's shrinking and compacting with heat applied. Try wicking a little tighter and make sure that the ends of the wick touch the deck of the atty on both sides. If it's hard to get though the coil, pull it back and forth to size it until it slides back and forth with less resistance. You don't want the wick to be choked in the coil. There's a sweet spot to find and sometimes you have to work with it.

 

[P-Funk]

I pulled out the second wick (or tried to!) It was in there so tight I had trouble removing it. When I did get it out, it was charred, with some very dark nearly black areas where it sat inside the coil that did not rinse out with running water. The stiff twisted coil provided enough lateral resistance to allow me to jam it in there very tightly. I guess this is a testament to the wicking power of rayon--I used that burnt mess for almost a full day and it worked reasonably well even though I had it packed in so tight I couldn't get it back out!

It is worth noting that I have been using this same tight wicking strategy for months on the Ares without noticeable ill effects. My coils on that deck used the same dual-strand twisted 28 gauge kanthal wire, but were larger at 3.0mm inner diameter and perhaps not so stiff as a result. I never had trouble removing a wick from those builds.

So, I burned off the residue, scrubbed the deck clean with a toothbrush, and rewicked with less rayon. I used DaveP's suggestion to slide the wick back and forth a few times to get it thinned a bit and sliding easily. The wick was very apparently more sparse when I was packing it down into the wells... it almost seemed like there wasn't going to be enough wick down in there!

Initial results seem promising. For this latest wicking the Berserker is sipping very nicely with no burnt flavors or leaking. Heavy brown discoloration is immediately apparent, but I 'm fairly certain it has not been caused by a burning wick.

Thanks for the assistance, folks. I'll post back later after I rack up a few dozen hours on this wick (assuming it lasts that long) to let you know how it worked out.

 

[IDJoel]

The wick material I am using is actually Graham Beauty CelluCotton 100% Rayon #44130. It is a 40ft box, not 100ft. I must have confused 100% with 100ft. And Sally Beauty with Graham Beauty. I should pay more attention when I try to provide background information! Pretty sure it IS actually rayon, as I have had much better luck with it than I have with cotton.

Yep; you look to be good. Graham's website lists #44130 as one of their rayon offerings. (#42251 is the cotton 40' box)

It is worth noting that I have been using this same tight wicking strategy for months on the Ares without noticeable ill effects. My coils on that deck used the same dual-strand twisted 28 gauge kanthal wire, but were larger at 3.0mm inner diameter and perhaps not so stiff as a result. I never had trouble removing a wick from those builds.

I don't have the Ares. But, folks that have both say the Ares is bigger (larger chamber?), and has more airflow at its tightest setting; than the Berserker does at its lowest. I would expect... using the same/similar coil configuration in both, at the same power... that the Berserker would be a warmer/hotter vape. Increased airflow helps to keep the coil cooler.

Also, if you are still using a 5-wap coil, of your twisted 28ga. kanthol, with a larger 3mm dia.; you have higher resistance (compared to the 5 wrap, 2.5mm dia. coil). That should result in a cooler output at the same wattage.

The larger diameter is also using more rayon. As @DaveP mentioned, rayon collapses a bit, when wet. More rayon, I would think, would equate to more collapse. And, therefore, more forgiving to over-stuffing. At least, that's what my addle-brained logic tells me.

So, depending on how much (if any) of my half-arsed reasoning may be true; I can see how you might be getting adequate performance from the Ares, but burning in the Berserker.

At any rate, I am glad your second round of wicking is working better than the first.
Let us know what your further experience tells you.

 

[sonicbomb]

My two pence.
I think both those coils have too much mass for the power you are using on them. Juice is not being properly vaporized and is gunking the coils up.
For your first build at 15W I would use half the number of wraps.

 

[P-Funk]

So it's been 5 or 6 days and I changed out the wick this morning. Wick was easily removable. No burning has occurred. Wick rinsed clean to white except for directly under the coil, where a slight brownish discoloration remained.

Wicked again on the same coil in the same fashion and again immediately (only few puffs in) brown discoloration is visible.

I am working on testing out a whole crop of new MTL RTAs, today built on the Ehpro True alongside rewicking the Berserker. Brown discoloration was not immediately visible on the True build, though I was using the same juice.

Coil setup was different though so that could be a factor as well. More experimentation to follow...

 

[halbgott]

I noticed this happening after I started using a mtl tank with a small chamber, it also seems worse with salts vs freebase. Bottom airflow also seems to cause issues. I use a 50/50 unflavored liquid also. So every two days I'm cleaning gunk and replacing cotton using .99@12.7 watts. I wish I could fit a high resistance SS coil for tc to test it out on my kayfun clone but there's not enough room.

 

[Gentle Smoke]

I will not profess to know how to diagnose P-Funk's problem as I'm new to rebuilding myself. However, I'd like to share a few comments with the novices listening in. I have a new Dead Rabbit RTA. I originally started wicking it with 2.5mm ID coils. I subsequently moved on to 3mm and had a miraculous improvement in vape density. I was inclined to believe that the increase in size was the reason for the improvement until I read this ECF article. Rayon Wick - Better Flow, Flavor, Longevity, and Nic Hit!! - Pt.2 It appears that my rayon wicking ability may be the main reason. Although the article doesn't state this, it appears that cotton moves juice by osmosis and rayon by surface tension. Hence with rayon the area with greatest mass will pull the most fluid. So it would appear that moving your rayon wick back and forth in the coil is inadvisable and greatly thinning your tails is.