Most coils will sizzle and or crackle. That's normal.
This depends on what you mean by "overheating." Most tanks will get at least warm if you chainvape them and some warmer than others. This isn't necessarily a problem either. There are several factors that will contribute to how warm a tank or RDA will get in use.The tank stopped overheating
Well with 3 fast hits (kinda chain vaping) and 70 watts on a pair of .25 ohm coils it doesn't necessarily mean anything is very wrong either, but it can be dialed in even more. You might try a LITTLE less cotton now. How tight it is in the coil itself and how tight it is in the ports will have a direct impact on how well it wicks under different circumstances. Experimentation is everything. You're definitely way ahead of where you were yesterdayHowever, at 70W and taking 3 fast hits one after another, I started tasting a little burned taste in the last hit. Maybe I put too much wick inside?
Like I say. Excellent progress made here. You aren't stuck with those coils either ya know1/3 of a tank gone (8ml) and not even a drop leaked so far- I just unscrewed the tank and had a look underneath. Juice I'm using is 70/30.
How much resistance did you get when pulling the cotton through the coils?
And could you still at least move the cotton around A BIT in the ports? Meaning it shouldn't be packed in hard either.
I have to be offline for a few hours, but I'm certainly not the only person who can help either.
Congrats on the great progress you're making!