I just dunno any more. This is going on for like the past 2-2.5 weeks....
Whether I am using the Exocet, Insider or VapeShell, all with 3mm ID SS316L wire in TC mode 22w @ 420F...wicked as minimal as possible without leaking and also not so much to get dry hits, tight in the coil and fluffy and loose on the ends...also tried loose in the coil and fluffy on the ends...and also tried almost too loose in the coil (pulls right out) and no change to the problem no matter how I am wicking. It's like the wicking makes no difference.
Each atomizer head starts out GREAT, an amazing vape, and then about on the 6th refill of the boro, I start getting sort of burnt hits...even with a full boro of juice, and if I empty the boro and take out the atty and look at the cotton, it is still wet, and if you squeeze it, plenty of juice comes out...
With each atty, when I it take apart, there is minimal gunking or carmelization of anything on the coil, and the wicks are clean and no burn marks if I pull them out, which is expected and 'normal' since I am running just VG, nic and distilled water to make unflavored 98% VG, yes there are no sweeteners or flavors added here in my DIY juice.
I wonder if there are hot coil legs that are giving off the burnt taste. On the Insider and Exocet, there are minimal 'legs' on the coil maybe 2mm before it goes in under the screw, so not much there to overheat, and I'd think that the center of the cotton would be burnt out before the legs got hot enough.
The only atomizer head that does NOT have this problem is the Kanger-style RBA head.
I've tried different brands of SS316L that I have, Medusa Wire, and Master of Clouds, as well as different cotton, Puffs pads from Amazon, and Native Wicks Platinum Blend. I even made 2 other batches of juice. My usual has VG from Essential Depot, and the first alternate batch I used Raw & Rare VG (also from Amazon), and the second alternate batch I used the Essential Depot VG, but mixed with freebase nic, instead of the 'smooth' nic salts, both from Nicotine River.
Trying to do process of elimination here...I cannot think of anything else to try to resolve this.
I am open to ideas, no matter how far-fetched...please advise