Had my Joye 510 for 4 days now. The prefilled carts just were not working for me, always got a burning taste with them. I tried the PTB mod using my eliquid from TV. It worked great the first time, but after refilling it stopped wicking to the atty. Back to burning taste. So I've been dripping pretty much all the time, and it's been awesome, but it's a pain when driving to try and drip, so I really wanted a way to use a filled cart. Enter the ZFM mod. I followed the directions and was expecting a lot of leakage, but to my great surprise, I haven't had the slightest bit leak out yet (it's only been a few hours). No more burning taste either. It's still not as good as dripping, but it will do for those times when it's not practical.