Ohms getting higher?

[Reevo]

Hi All, been building for about a month ish now, but im confused about my rsst. I tried a steel rope wick with mesh top wrap on it (the same as 2 cobra clones and a Aga t 2 which all worked really well, average resist about 0.9 ohm) which didn't go to well.
Tried a few different wire gauges but not a lot of joy, in the end put it back to a steel mesh wick which works well BUT on my evic It started at 1.0 ohm then over about 2 weeks the resistance got higher, its now at 2.0 ohms?! Is this normal? Not sure if its the evic or what? Cant try the others on it as I get "atomiser short" due to low ohms. Any ideas or help?

 

[VaperCaper]

Resistance can change over time, though it's unusual for it to change that much.

Stuff expands when it gets hot, when it gets cool again it shrinks. As you use a coil this heating/cooling causes the length of the wire to grow and shrink slightly.

If you're using a rebuildable that's secured with screws it's possible for the wire to stretch a little or move around on the wick or pull through a bit and the longer the length of wire then the higher the resistance will go. Resistance also changes a tiny bit due to temperature.

If you're using a SS Mesh wick potentially the resistance can change a lot if you've not done the best job making the coil. As the wick and coil 'bed in' juice gunk coats the surface of the wire and the surface of the wick acting like an insulator. Say you have a hotspot on the bottom turn of the coil and instead of the electricity going through the resistance wire it's going through the very bottom of the wick instead. Electricity always takes the path of least resistance. Over time gunk builds up and gets rid of that hotspot and now the path of least resistance is the wire and not the wick, so that's the way the current flows. In that case the measured resistance of the coil will appear to jump up a bit.

With all that said if you can't run this coil on another device then it isn't at 2ohms. Any regulated mod will happily fire at 2 ohms if you get the low ohm warning then the coil must be below 1.3ish ohms as that's where the cutoff point usually is.

So resistance creep is normal, if you get jumps in resistance it's normally down to a poor build.