Let me start off by saying I’m a die-hard mouth to lung vaper. I’ve tried sub-ohming, and it’s great (for what it is). However I really don’t like hitting the fire button, inhaling for all I’m worth as quickly as possible in order for my subtanks to function properly. I was missing the calm, relaxing mouth-to-lung experience that I had grown to love for the past 30 years.
Enter the Kayfun style RTA.
On a whim one day I purchased an Hcigar Kayfun 3.1 (actually a Russian Clone) and was immediately blown away by the experience and flavor. This was nirvana!! I really loved it, but was underwhelmed by the side-fill port. So I started using the tried-and-true ‘top-fill-turn-close-air-hole-recap-turn-upside-down-tighten’ fill method. While this was effective, it became tedious for simply refilling the tank and I started longing for something a bit simpler.
Enter the Kayfun v4.
I finally broke down and purchased a couple of KF4 1:1 replicas (since I can’t’ afford to drop $160 on an authentic) and I ABSOLUTELY LOVE how easy refilling this thing is. The flavor is amazingly good. I was satisfied with the KF4 but I noticed just the tiniest little bit of moisture was getting into my airflow causing a slightly annoying not-quite-gurgle with every draw. After doing a lot of research, the consensus is that the o-ring inside the base around the square-ish section is likely at fault. I’ve tried several different sizes of o-rings and can’t quite get it to stop the phlegm-like gurgle.
Enter the hybrid.
Since I had several Kayfun style tanks to scavenge parts from, I decided to see if I could come up with some sort of compromise, and I think I got lucky. I had a couple of FT Russian 91% clones laying around and discovered that the short bottom chimney section was the exact diameter of the chimney in the KF4. All I needed was a way to seal that chimney to the inside wall of the KF4 cone section. I stacked a couple of o-rings inside the cone, assembled the works and EUREKA!! The ease of filling the KF4 (still need to cover the air hole on the base) with the flavor and performance of a Russian 91%.
If you’re as finicky as I am when it comes to something working properly and can’t afford the performance and reliability of authentic top-shelf RTA’s you might get lucky by trying something like this.