The trick to good wicking is to have good wick with straight fibers, and knowing how thick and long you need to put in.
Note: This guide concentrate on cotton (see info on using rayon and hemp below), but even other type of wick is technically the same, except that you may need to make it tighter and use a larger thickness due that while cotton swells as it's saturated, other type of wick material such as hemp (that I'll use once in a while) or rayon(which I've yet to try) stays the same (no swelling) or even shrink a bit. More on this later.
It should be firm going in the coil, but not overly tight at all, you need it to be fluffy, touching the whole coil across. The length should provide you with a bit of fluff at the end of the coil before going down (like a tiny bit of it going up first before going down) to the liquid feed. For most tanks, you should only have the tips going in, so to create a "suction" that pulls the liquid onto the fibers.
The ends should be cut firmly and clean. The goal is to fill the liquid intake holes and block them to prevent flooding or leakage, BUT without having too much as that would clog/block the feed/wicking.
If you are using the square pads, just look up videos about "Scottish roll"... it's basically stretching out the cotton against the grain (the direction of the fibers) then rolling it (with the grain) into a "tube". This creates a "tube" where the long fibers are aligned and creates a better spacing between the long fibers for the liquid to travel easier.
To measure how much, try to go for a thickness that would be about the same size as the outside diameter to the coil while being as fluffy as possible. The goal is that you want it to fill the coil well so that once it expands once wet (as cotton swells up a bit) so that you do not have gaps, but you don't want to sticking out through the wraps. You want to get it to be in contact with the coil for the full length.
One thing I consider a mistake that I see on many videos is that the person pulls the wick down at the ends, creating such a gap and can cause the legs and tips of the coils to be warmer as they aren't cooled by the flowing liquid through the wick.
My technique consist of taking the amount (thickness), working it with the tip of my fingers to stretch it out, evening out the fibers, similar to hand rolling a cigarette and rolling the paper. I then give the whole length a twist so that it's slightly compressed and squeeze the tip to have the needle/threading thing going.... I keep twisting as I insert it through, measure how much I need, cut and continue and thread the second coil. The amount of wick, if correct, should be firm, but should fit well, aka it you tug on it and it was to rip/break off, then it's too much, if it just slides out really easily, then not enough. It needs to be able to slide out but with some fair amount of resistance (once untwisted).
Once the cotton is threaded, I untwist and work it slightly until I can see that it's firm against the inner wall of the coil.
For the length.... this completely depends on your deck. You need to judge how long you need for it to make it to the feed holes then add a bit.
The extra should be used as your "reserve" on the ends of the coil by having a bit of it going upward a tiny bit before going down towards the feed holes. This also acts as a "padding" to have between the coil and the walls of the bell.
Note: the wick needs to be such that you do not block the airflow whatsoever.
At the feed holes, you can trim the edges so that your wick is clean and straight, with a bit of an angle cut if needed.. your wick can be "cone shaped" (trimmed to be a bit pointy) at the tips if your deck so requires it. Your goal is you want to fill the feed hole, so that all liquid present will get "sucked in" by the wick's tip and none passes by it (leak out). But you don't want to clog it, so while "full", the feed isn't blocked off.
For most decks (RTAs), the best approach tends to be to get the wick into the wick feed "hole" (or such), try to have an angled or tapered tip, and to actually have a bit of empty space, so that at the very bottom of that feed hole, only a very small amount of cotton (as in a few strands) will actually touch the bottom, while the rest of the bottom is empty to allow the liquid to get it and be sucked up by the wick's tip/ends that's just above the bottom.
Here's an example (rda) that the wick has been in use for a while now. You can see that even after an extended time, the coil is "full" and the cotton looks firm in place, the outside edges are square instead of pulling down. While the cotton is darker in colour due to the liquids used, the coil itself is still clean, indicating that the flowing through the wick in working quite well.
View media item 430319
Extra notes about alternative wicking material:
For hemp: this looks like couch stuffing, and is sold usually in small packs, and isn't straightened (at least the stuff I got), so I have to take a pinch-full and work it by pull it gently so that I "comb" the fibers gently so that they get as much straight fibers as possible. Hemp doesn't swell up like cotton so I have to get similar thickness as cotton, and add a bit and hold it firmer and twisted during insertion.
Rayon: (new edit) I've started to give rayon a try a few weeks ago, and as others have state, it does need to be make fairly tight in the coil as it shrinks a bit instead of expanding like cotton does, you have to fill the coil much tighter (have a bit of a squeak when pulling it through) and then trim the tips that goes to the feed holes or bottom of an RDA so that you have as little as possible while still "blocking the holes to prevent flooding. These tips NEED to be frayed as much as you can as one thing I've notice is that rayon turns into what I'd describe as "gel-like" and simply stopped wicking as well as when new after a while. Because of this, I find that it's got a shorter lifespan than cotton, but then, cotton tends to be also worn out differently after a while. So it is better or worse? The difference tends to make them even... cotton wears out and have a slight break in, rayon starts "gelling" after several tanks, but has almost no break in time.
SS mesh: nope, I'm not touching this one ever, between the risk of metal shards, the fact that you need to oxidize the mesh to make it non conductive, and so on, I won't even bother saying more on this.
Let me know if I missed something, and please go read and enjoy all my other entries as I'm building my blog, I'm trying to cover every aspect of vaping that I know about. I'll keep adding items as I think of them and have the time to write them.
Note: This guide concentrate on cotton (see info on using rayon and hemp below), but even other type of wick is technically the same, except that you may need to make it tighter and use a larger thickness due that while cotton swells as it's saturated, other type of wick material such as hemp (that I'll use once in a while) or rayon(which I've yet to try) stays the same (no swelling) or even shrink a bit. More on this later.
It should be firm going in the coil, but not overly tight at all, you need it to be fluffy, touching the whole coil across. The length should provide you with a bit of fluff at the end of the coil before going down (like a tiny bit of it going up first before going down) to the liquid feed. For most tanks, you should only have the tips going in, so to create a "suction" that pulls the liquid onto the fibers.
The ends should be cut firmly and clean. The goal is to fill the liquid intake holes and block them to prevent flooding or leakage, BUT without having too much as that would clog/block the feed/wicking.
If you are using the square pads, just look up videos about "Scottish roll"... it's basically stretching out the cotton against the grain (the direction of the fibers) then rolling it (with the grain) into a "tube". This creates a "tube" where the long fibers are aligned and creates a better spacing between the long fibers for the liquid to travel easier.
To measure how much, try to go for a thickness that would be about the same size as the outside diameter to the coil while being as fluffy as possible. The goal is that you want it to fill the coil well so that once it expands once wet (as cotton swells up a bit) so that you do not have gaps, but you don't want to sticking out through the wraps. You want to get it to be in contact with the coil for the full length.
One thing I consider a mistake that I see on many videos is that the person pulls the wick down at the ends, creating such a gap and can cause the legs and tips of the coils to be warmer as they aren't cooled by the flowing liquid through the wick.
My technique consist of taking the amount (thickness), working it with the tip of my fingers to stretch it out, evening out the fibers, similar to hand rolling a cigarette and rolling the paper. I then give the whole length a twist so that it's slightly compressed and squeeze the tip to have the needle/threading thing going.... I keep twisting as I insert it through, measure how much I need, cut and continue and thread the second coil. The amount of wick, if correct, should be firm, but should fit well, aka it you tug on it and it was to rip/break off, then it's too much, if it just slides out really easily, then not enough. It needs to be able to slide out but with some fair amount of resistance (once untwisted).
Once the cotton is threaded, I untwist and work it slightly until I can see that it's firm against the inner wall of the coil.
For the length.... this completely depends on your deck. You need to judge how long you need for it to make it to the feed holes then add a bit.
The extra should be used as your "reserve" on the ends of the coil by having a bit of it going upward a tiny bit before going down towards the feed holes. This also acts as a "padding" to have between the coil and the walls of the bell.
Note: the wick needs to be such that you do not block the airflow whatsoever.
At the feed holes, you can trim the edges so that your wick is clean and straight, with a bit of an angle cut if needed.. your wick can be "cone shaped" (trimmed to be a bit pointy) at the tips if your deck so requires it. Your goal is you want to fill the feed hole, so that all liquid present will get "sucked in" by the wick's tip and none passes by it (leak out). But you don't want to clog it, so while "full", the feed isn't blocked off.
For most decks (RTAs), the best approach tends to be to get the wick into the wick feed "hole" (or such), try to have an angled or tapered tip, and to actually have a bit of empty space, so that at the very bottom of that feed hole, only a very small amount of cotton (as in a few strands) will actually touch the bottom, while the rest of the bottom is empty to allow the liquid to get it and be sucked up by the wick's tip/ends that's just above the bottom.
Here's an example (rda) that the wick has been in use for a while now. You can see that even after an extended time, the coil is "full" and the cotton looks firm in place, the outside edges are square instead of pulling down. While the cotton is darker in colour due to the liquids used, the coil itself is still clean, indicating that the flowing through the wick in working quite well.
View media item 430319
Extra notes about alternative wicking material:
For hemp: this looks like couch stuffing, and is sold usually in small packs, and isn't straightened (at least the stuff I got), so I have to take a pinch-full and work it by pull it gently so that I "comb" the fibers gently so that they get as much straight fibers as possible. Hemp doesn't swell up like cotton so I have to get similar thickness as cotton, and add a bit and hold it firmer and twisted during insertion.
Rayon: (new edit) I've started to give rayon a try a few weeks ago, and as others have state, it does need to be make fairly tight in the coil as it shrinks a bit instead of expanding like cotton does, you have to fill the coil much tighter (have a bit of a squeak when pulling it through) and then trim the tips that goes to the feed holes or bottom of an RDA so that you have as little as possible while still "blocking the holes to prevent flooding. These tips NEED to be frayed as much as you can as one thing I've notice is that rayon turns into what I'd describe as "gel-like" and simply stopped wicking as well as when new after a while. Because of this, I find that it's got a shorter lifespan than cotton, but then, cotton tends to be also worn out differently after a while. So it is better or worse? The difference tends to make them even... cotton wears out and have a slight break in, rayon starts "gelling" after several tanks, but has almost no break in time.
SS mesh: nope, I'm not touching this one ever, between the risk of metal shards, the fact that you need to oxidize the mesh to make it non conductive, and so on, I won't even bother saying more on this.
Let me know if I missed something, and please go read and enjoy all my other entries as I'm building my blog, I'm trying to cover every aspect of vaping that I know about. I'll keep adding items as I think of them and have the time to write them.
