Wick darkening/burning quickly

[nicobeak]

I have noticed with my rta that the wick (I've used both cotton and rayon) is darkening/burning in just a day or two. I don't know if this is normal or not, and I can post pictures next time I take it apart to rebuild. My theory (probably wrong) is that since I am using 30g wire, it is heating up too much too quickly. Here is some pertinent information:

I run it around 15-17 watts regulated

30g about 1.5ohm 3/32 diameter in an orchid

happens with both cotton and rayon

doesn't ever taste burnt and I don't get dry hits

it happens with multiple liquids, even pretty clear ones

I think that is all my variables. Is it normal to get this darkening/burning of the wick the next day, or is it because I am doing something improperly? I may try building with 28g next time and see (I don't know if heat flux can cause this type of thing).
Any info is appreciated, thank you.

 

[MattyTny]

With 30 gauge on a 3/32 at 1.5 ohms I'm guessing you have something like 5-6 wraps. That's a lot of concentrated heat on one part of the wick with a thinner wire. But as long as you have the airflow and proper wick it shouldn't burn too badly. I would suggest 28 gauge and more wraps/smaller coil internal diameter to hit your target resistance. More surface area wick to coil contact is what a lot of people suggest.

When you take out your wick wash it with water and check for burning. Darkening will wash away and burn marks will show up as dark charred wick. I've had wicks that looked very dark, but after a wash it's white as when I put it in.

 

[Reloader45ACP]

My favorite setup so far is a Plume Veil on a mechanical, set fully open, with dual coils, 26g, 6-7 wraps for .3 Ohms with cotton wicks. I can usually do 6-8 five-second puffs before needing to add more juice. I smoke for 20 min in the morning, 10-15 min during my lunch, 20 on my way home, and about an hour at home. So I vape a good amount I would think.

My wicks will easily last for two weeks, even when I use some really thick stuff (e.g. stuff that looks like honey but isn't allowed to be discussed on these forums). If my wick gets dirty and I want to clean it up, I just flood it with clear ejuice, take 6-8 puffs, and repeat. Three cycles is usually enough to bring my wicks back to white. Just got to be careful not to get to much of a dry hit. You want to get close to getting a dry hit, so juice from the middle gets pushed out to the coils, but not so dry that it burns the cotton. Now there is a bit of a learning curve, so expect to burn your cotton wicks a couple times, but the good news is you will learn the limits of the cotton wicks pretty darn fast.

When I first got my RDA setup, the guy who built it for me told me to wait two weeks, so I didn't know any better. Of course, I burned the first wick the same day I got my RDA, but after that I learned to keep the cotton moist at all times. Now that i know how to change the wicks myself I change them out about twice a week, for no reason other then I'm bored.

 

[nicobeak]

Matt,
Thank you, I'll give the 28g w/ smaller diameter a try. I didn't think about washing them off to see if it was burnt or just gunk, that's a good idea. Next time I pull it apart I'll do that.

 

[readeuler]

With rayon, the tails darken when the wick is too thick close to the coil: the thick shoulders will pull the residue away from the coil. I've been amazed at how thin of tails you can get away with using rayon, as long as as you're not pushing too many watts (15-17 is definitely not too many).

I have found that it's harder to keep wicks from darkening in an RTA compared to a dripper, for whatever reason.

 

[nicobeak]

With rayon, the tails darken when the wick is too thick close to the coil: the thick shoulders will pull the residue away from the coil. I've been amazed at how thin of tails you can get away with using rayon, as long as as you're not pushing too many watts (15-17 is definitely not too many).

I have found that it's harder to keep wicks from darkening in an RTA compared to a dripper, for whatever reason.

That is good information too! I just started messing with rayon because someone gave me a little to try, so your experience is definitely appreciated. I am sure my shoulders are too thick, I'll try thinning them out next time. I am pretty amazed with the rayon at this point, and will have to invest in a box of it. I have noticed the darkening in RTAs is worse as well, I think it might be related to chamber size and dissipation of heat.