I can pretty much rule out it's not my builds being faulty or loose connections, I've been building Kayfun's for over a year now and I've pretty much got it down. My Kayfun's make connecting with the pin just fine, they sit nice and flush and pick up a reading before I even screw it down completely. I've rebuilt both my Kayfun's three different times now each and I get consistently inconsistent results with my DNA40 lol. I have a feeling what RandyF says about the coils changing shape or whatever because they are so soft after constant heating cooling, and reheating over and over again. This is having an impact on the ohm's lowering as both my Kayfun's have acted identically now with three different builds on them each.
Just a side note I will say that using microcoils have never been my thing although I can build them just fine. I find after I take apart my atty there is always black burned junk on my coils, almost like burned cotton sticking to the coils, even on this DNA40. I have noticed in the past that I would lead to a bad slightly burny taste after a short time using microcoils in Kayfun's on mech's, as opposed to using spaced coils. I've always kinda preferred spaced standard coils to microcoils. I may try twisted 28awg or 30awg spaced coils and see if I can get a better result and maybe a sturdier coil perhaps.
I spent a ton of time and almost an entire 100ft spool of Ni200 trying to find the perfect Ni200 Kayfun build to suite my tastes... settled in on a 28AWG 7 wrap spaced coil on a 1/8" mandrel, comes out to .11ohm. Wicked with Koh-Gen-Do cotton. I slightly work harden the wire with a "Z-Pull" method - 10 pulls, any more and it gets too brittle for me, any less and it's too soft/pliable. (See
How to Work Harden Wire - YouTube for an example of how to do it.) I then wrap it as tightly as possible using a jig and a lot of tension - one end of the wire is clamped to something, just as in the video when I wrap the coil on the jig. It starts out as a perfect contact coil, and I then gently pull the coil apart from both sides evenly, then compress it back together with my thumbnails in order to get it sized properly.
I mount it perpendicular to the deck screws. Lift it up to about 2-3mm directly above the air hole.
I then set TP to 450F, turn the watts up to 25 or so, and dry fire it. If you have any hot turns they will glow instantly and TP will immediately stop that glow. Fix those with a micro-flathead. Dry fire again, make sure there are no glowing wraps. When you dry fire with TP on, there should be absolutely no glowing. Once this is confirmed, wick, fill, vape away.
I typically run this config around 14-18watts and TP set to taste (based on juice). This has worked very well for me (FINALLY!)
