Here we will discuss the basics of rebuildable atomizers.
There are three primary types of RBAs, the tank, dripper and dripper tank. A tank RBA is referred to as an RTA. A dripper atomizer is referred to as a rebuildable dripper atomizer (RDA). A dripping tank is called a rebuildable dripping tank atomizer (RDTA) some are called a squonk tank. There are bottom fed atomizers where a pump (manually worked by your finger) flows juice up through the bottom of the atomizer to the build area and require a squonking mod. These are called squonking APVs. Squonking RDTAs allow me to squonk without a special mod. The pump is built into the atomizer. Some RDTAs however have a juice reservoir with holes at the bottom of the tank that drip juice onto the build below without the need for squonking.
A dripper is so named because I drip juice down the drip tip from a bottle to saturate the wick. A tank is so named because I fill the tank as opposed to constantly dripping all day long. I find dripping too inconvenient for my use especially when RTAs and RDTAs have given me as good a vape experience as RDAs. I have over 60 different atomizers including RTAs, RDTAs and Glassomizers. I have one RDA.
The tank atty is so named because it has a tank that holds the eLiquid. Prior to the tank atty was a cartridge or “carto” that was packed with absorbent wicking material that was saturated with eLiquid just like a dripper. With a carto I dripped juice into the end. A “clearo” was a great improvement over cartos as the clearo was a plastic tank that held more juice and could accommodate larger coils. Then there were carto tanks and carto punch tools where I strategically punched holes in the self contained carto so the juice could flow into the carto. A “glassomizer” was an improvement to clearos in that a glassomizer used glass for the tank instead of plastic. In any atomizer there is an interface between the juice reservoir and the heating coil. This is called the wick. The wick transfers eLiquid from the reservoir to the heating coil.
The clearo and glassomizer eventually evolved from the cartridge coil into the RTA. A rebuildable tank atomizer is an improvement over all because it is cheaper than buying replacement coil cartridges and I experimented with different wicking materials and sizes of heating wire, coil diameters and lengths etc. for the particular APV capabilities and eLiquid viscosity. Even though the replacement coil cartridges are designed to be disposable, it is possible to rebuild some of those in cartomizers, clearomizers, and glassomizers, I’ve done it and I will show how below. But a true RBA can make rebuilding much easier because RBAs are designed to offer easy access to the coil/wick build deck, provide easy connection of the coil legs, and have a larger area for the coil/wick build.
At the heart of any atomizer or vaporizer today is a wick and heating element.
The genesis or “genny” style RTAs, examples shown above, had the tank of juice below the wick/coil build. RSST on the left and the Arnold on the right. These often resulted in hot vapes and you ended up having to tilt the device the correct way to get enough juice to flow to the build so you don’t get a dry vape. They were built by using SS mesh, silica rope, SS rope or ceramic rods for the wick. The SS mesh and rope had to be oxidized by burning with a crème Brule’ torch and VG so the coil wouldn’t short out when wrapped on the wick. It was common to oxidize several times and even after wrapping the coil on the wick moving the wraps up and down while firing to eliminate hot spots. The SS mesh had to be rolled up very tightly into a compact cylinder as shown above on the left on an RSST. Although not intuitive, I found that with 100% VG, 500 mesh worked better than 400 mesh. The numbers mean how many strands are in the mesh per inch. The SS rope could also be sheathed with silica as it was difficult to oxidize as shown above to the right on the Arnold. We even experimented with porous ceramic rods like the FC2000. But I always found the mesh to be far better and not as fragile. Kanthal was wrapped around the wick and the coil legs secured to the positive post and ground screws. I still have a few genny RTAs but merely as conversation pieces as they are essentially obsolete. I do not recommend these at all as they are a pain to use and give a hot vape. With the onset of clearomizers and glassomizers with coil cartridges, atty designs moved to a bottom coil design and were the next big improvement in RTAs that came with the venerable Kayfun (KF) from SvoёMesto. And in the atomizer world, the KF was the face that launched a thousand ships. Many RTAs today use a KF style build deck either single or dual coil. The KF is shown below.
Typically the heating element in an atomizer is a simple coil of wire but others include twisted wire, Clapton wire, flat ribbon wire and ceramic chips or disks called vapin donuts. Either the wire is wrapped around the wick or the wick is wrapped around the coil. The wick saturates with eLiquid from the reservoir and flows it to the coil. As shown above on a KF, the coil ends are attached to screw posts (one is ground, the other is positive) and the wick ends are sitting on juice channels. When the chimney is screwed on that seals the vaporizing chamber from the eLiquid reservoir.
These coil cartridges shown below provide the same function as shown above. The coil cartridge has a body that serves as the vaporizing chamber and part of the chimney. The coil and wick are tucked away inside. A coil cartridge is used in clearos and glassomizers as a user replaceable part that is intended to be disposable and easy to replace. The head is comprised of a body, wick and coil. The body is typically made of thin wall stainless steel and will be threaded on one or both ends and contains the wick and coil. The coil cartridge is installed in the tank and serves as the center of the atomizer isolating airflow from the e-liquid reservoir. Air flow is through the insulated positive pin at the bottom. The wick can be a ceramic tube as shown on the left or can be woven silica rope shown on the right, tufts of cotton or even Rayon. The picture in the middle is a vertical coil cartridge.
The coil cartridge has holes in the side for the e-liquid to pass from the tank to the wick. The heating element wire is then wrapped around the wick or the wick wrapped around the wire and mounted inside the head.
The primary difference between a rebuildable atomizer and the coil cartridge atomizer is that in a rebuildable, only the wick and coil is disposable. In a coil cartridge atomizer, the coil, wick and cartridge body are disposable. With that said, it is possible to rebuild the coil cartridge but being so small, are not easy. Regardless, they all have this in common: black gunk builds up on all coils regardless of a coil cartridge or a rebuildable, they both use a wick and heating coil and they both have an air inlet and mixing chamber.
In fact those cig-a-like cartomizers as shown below are an atty but not easily rebuildable.
They have a drip tip, coil, wick, chimney, air flow and juice flow. The juice reservoir is extra wicking stuffed in the body that is saturated with e-Liquid. Most of them have silicone rubber end piece that I can pull out and drip more e-Liquid in if I like. And while technically they can be rebuilt, they are not designed to be rebuilt and most require a specialized miniature welder.
Attys have lots of different designs, shapes, sizes, colors, and materials as shown below.
On the left is a cig-a-like cartomizers then a group of Fogger RTAs in different colors including one in brass, then a group of clearomizers in various colors that use coil cartridges and far to the right is a dripper without drip tip. I use a dropper bottle to drip drops of juice onto the coil and wick in a dripper. Drippers are also packed with extra wicking to serve as a juice reservoir so I don’t have to drip as often. Tank atomizers require filling and then self-feed. I should note that there are also hybrid dripping tank atomizers (RDTAs) and bottom fed drippers that use a tank. The RDTA usually has a spring and drip is activated by pressing down on the drip tip. Bottom fed dripper tanks are usually built into the mod and most require pushing a button to feed juice from the tank into the atomizer. I prefer tank atomizers that require infrequent refilling and will therefore spend the rest of this chapter talking about tanks atomizers.
The drip tip is the tip of the atomizer that I put my lips on to inhale or “draw”. Some have a removable seal where I can drip e-Liquid into the carto to “recharge” it. On other atomizers, whether they are a tank or dripper, the tip is called a drip tip. Some drip tips are removable some are fixed. Of the removable variety some are threaded some are not. The drip tips that are threaded are specific to that atty. Of the non-threaded removable drip tips some are universal “510” drip tips while others are unique to a product line or unique to a particular atty. The “510” designation comes from the atty connector. Some are universal 510 / 808 / 901 series that are 9.2mm diameter. However some are larger and threaded as in the CE4 / CE6 / Vision Stardust or different size like the the LEO / RiVa-T / 801 / 302 and none of which are to be confused with the Vivi Nova CE6 which some 510s will fit. I know, it’s ridiculous. I prefer attys that take a standard removable 510 drip tip as that is the most common and offers the greatest variety. Drip tips come in many different designs, shapes, colors and materials. Some people prefer soft drip tips while others like theirs hard. Drip tips come in SS, glass, delrin, silicone, marble, PVC etc. The drip tip can also affect the vape experience. Long drip tips cool down the vapor. Drip tips that have an adjustable airflow port promote intermix for clouds but weaken the flavor density. This is called slip streaming..
By far the best materials for an atomizer are stainless steel, ceramic and glass. Plastic can deteriorate with some e-Liquids while brass and copper will corrode and can act as a catalyst for organic reactions. Aluminum has been used and should be avoided as well because it will corrode over time, even if anodized. The VG and PG itself isn’t the problem. But some flavorings especially citrus can have an unbalanced pH. With that said, glass and ceramic are fragile while plastic is not. Clearomizers use plastic for the tank and glassomizers use glass. Some glassomizers use a SS over-cover to help protect the glass. Even with that, some people prefer the plastic clearomizers due to their resiliency in accidental bumps and drops.
While we will talk design and features later in the chapter that I use to help pick an RTA, the one thing I always remember is to clean it.
I clean all attys even if there is a label that says it is RoHS compliant and there is no funky smell. Just go ahead and give it a good clean. It is also always good to do a thorough inspection after cleaning. Look for shavings, incorrect milling and etc.
On a tank atty, the vacuum created in the chamber helps draw the juice into the wick and coil. As the atty heats up, the liquid flows easier but it is the vacuum created by our draw that pulls juice into the vaporizing chamber the most. As juice is drawn into the vaporizing chamber, air is back fed into the tank. A tank atty that is flowing will produce bubbles rising in the tank during vape. This is good and is a clear sign the atty is feeding juice well. Bottom coil devices also count on gravity to help flow the juice. But even then, it is vacuum that does the most to pull in juice. The viscosity of the e-Liquid has a dramatic impact on the flow rate of e-Liquid as well as the design of the atty itself and wick used, both material and amount. The more juice that flows, the more power the atty can sustain.
It is common to encounter leaks and floods on tank attys. If the atty is leaking, that typically means it has a bad o-ring or seal at the top of the tank. If the atty is flooding only when filling, try closing the air intake when filling. There are a few ways to clear a flood. The first method is to crank the power and vape off the excess. But not all floods will clear this way. Sometimes just inverting the atty upside down will let the extra juice drip out of the tip. Then using a q-tip to swab the inside of the drip tip and chimney removes the juice. If that doesn’t work, blow into the tip and this will blow juice out the air inlet hole(s) – best to wear gloves and a paper towel ready when doing either of these methods. I have also had attys that won’t leak until they flood. Once flooded they start a siphoning process that left alone will empty the tank. Floods and leaks can be very messy and if without wearing gloves, can give a massive sudden nicotine dose so I always wear gloves and wipe down the tip as I don’t want raw e-Liquid on my lips or tongue either. And as always, if I were to get e-Liquid juice on me, I wash immediately and seek medical attention.
Atty designs that allow the coil and wick to be positioned directly over the air intake stream in the chamber vape better. This is because the air flowing over the coils increases vapor intermix with the air. Yes the airflow also cools down the coil and wick but not nearly as much as juice flow does. However once power is increased to a point, the cooling effect from air is negligent as juice flow has not increased and you are starving the coil and once again are back to a dry vape. But it is the intermix of intake air and vaporized e-Liquid that produces the vapor stream. More intermix creates a more evenly dispersed mix.
Every atty has an inherent design limitation on how much juice it can flow without leaking or flooding and therefore how much power it can safely sustain. The amount of mass heated, both liquid converted into vapor and air intake that gets heated, determines power. The amount of e-Liquid converted into vapor depends on heated surface area in contact with e-Liquid. More vaporized e-Liquid to air ratio results in a flavor packed vape. Less vaporized e-Liquid to air results in a weaker not as yummy vape. What may not be obvious is the later creates a bigger cloud. Not as dense but more volume. That is one of the keys in atty design and selection criteria. It is not something advertised but knowing what to look for and reading online reviews can help understand these and other aspects better.
There are two primary questions to ask.
Do I like airy unrestricted draws or tight?
How much vapor do I want?
There are other considerations when choosing an atty. For example does it have air flow control? Does it have juice flow control? How is it filled? Is it rebuildable? Are replacement parts available? I’ll cover that question first. It is nearly a given that I am going to break the atty. From dropping it, that cat or dog knocking it over, it will get scrunched in my pocket or sat on in a car seat. Life happens..
Other than a basic inexpensive clearomizer, air flow control is a must for tank attys. I always close off the air hole when the tank is setting for a long period of time. Closing air flow control also helps when filling, especially if the atty is a top fill. And as already mentioned, restricting air flow to create more vacuum is necessary even if just for a few primer puffs to get the wick saturated. Juice flow control is a good feature to have especially on top fill attys. Sometimes an attys chimney can be screwed down a little or all the way giving some juice flow control. Other attys were designed with juice flow control that allow adjustment through a greater range of control. Sometimes this is the chimney or another part like a set screw. I detest needing a tool to fill my atty. I prefer to do it straight from a bottle. Needle bottles are minimum acceptable with a normal tip being preferred. There is an intermediate narrow tip that is commonly used. The point is, the attys inherent design will determine what bottle is needed to refill. So that is something to consider. Also whether it is top fill or bottom fill. Top fill tanks simply require taking out a screw or twist something to give access. On a bottom fill removal from the mod is the first step and then remove a plug or screw. But if the fill port needs a tool, then I have to carry that tool along with me as I travel. And it is because of that vacuum that we never want to fill a tank all the way. We need to leave an air pocket at the top of the tank. Fill an RTA 80%.
Let us start with a couple fundamental concepts. Short lengths of wick from juice reservoir to heating device are best for juice flow, keep the coil close to the juice supply to shorten the amount of wick the juice has to travel through to get to the heat. I call this “wick length”. Shorter wick lengths are also better for chain vaping. Keep as much of the entire coil immersed in juice as possible. I use Rayon or cotton instead of woven silica. Rayon wicks better IE flows more juice than cotton from a cotton ball and cotton flows more than silica. The rule for cotton is “less is more”. This means use less cotton to wick more. That is because cotton has a tendency to expand slightly with liquid. Rayon not so much. So when wicking use less cotton than rayon. Cotton from a cotton ball has a tendency to pile up whereas Rayon strands are “aligned” better. Also use only organic non bleached cotton balls. If all I have are normal snow white cotton balls, they have been bleached and need to be boiled before use to remove the excess chlorine bleach. There is a better type of cotton called “Japanese” cotton or organic cotton (OC) that has been tested to show it wicks slightly better than Rayon shown below.
Sometimes referred to as KGD cotton which is short for Koh Gen Do. Other brands can work just as well. I use the Selena organic cotton puff. It’s cheap, organic, unbleached and readily available. You will find Muji OC pads on various sites but most of them have been bleached. I tell by the color. If the pad is white it has been bleached. If it is an off-white cream color then that is unbleached. These Japanese cottons, like rayon, have fibers that are aligned better than cotton from cotton balls. The puffs have a tougher outside layer that I peel off and discard (both sides) so I can use the softer puff inside. Simply cut strips (shown above) along the grain, not across, to thread through the coil. Threading is accomplished by taking one end of the wick and rolling it while pulling it between thumb and forefinger. This will thin out the end into a point that can be clipped off to eliminate “scragglies”, singular fibers that might hang up as I try to thread the wick through the coil. I also make a couple snips on the ends to make the rolling into a point easier. Once rolled and snipped, the point can be threaded through the center of the coil and grasped on the other side to pull the wick through.
The goal with any wicking is to ensure the entire inside of the coil is being touched by wick. If the wick isn’t touching every point inside the coil then it is not enough wick. But don’t get the wick packed so tight that when I go to thread it, the wick distorts the coil spacing. Especially with cotton as less is more because it swells when wet. If this happens, I strip a little wick off the tuft and try again.
In the picture above is a tuft of Rayon at the top, cotton ball on the right and at the bottom from the left is SS mesh, SS rope and woven Silica rope. Right in the middle is a 510 to eGo adapter. The SS mesh and rope were used on genesis style atomizers. The silica can be used on just about anything though it always frays when cut or abrades by wrapping wire around it. Which is why I no longer use it. When making a silica build, I wrap the wire around the wick. Usually a needle is placed alongside the silica rope to give it rigidity as I wrap the wire then pull the needle out when done. As I always end up poking myself with a needle I preferred to use piano wire. Silica wick has been sold with the words “eco”, “bio”, “wool” and even “ceramic”. None of those are true. Neither is calling it fiberglass even though it is literally made from fiber of glass.
Fiberglass is a type of fiber reinforced plastic where the reinforcement fiber is specifically glass fiber. The glass fiber is made primarily of SiO2 but it contains some percentage of other oxides that modify its properties for a particular application. Common fiberglass modifiers are calcium oxide (CaO), magnesium oxide (MgO), aluminum oxide (Al2O3) and boric oxide (B2O3). Applications include insulation or making a boat. Silica is SiO2 which is glass. Reputable silica wick (rope and woven tube and sheet - paper and matting and flat stock) is literally made of glass fibers. Not exactly fiberglass that we think of that has other stuff in it. I always laugh when I see terms like "ceramic", "wool", "bio", "eco", and etc used when talking about silica wick.
Below is a true ceramic wick. It is a hollow tube not fibers. When I think of ceramic I think of pottery not a woven rope.
It is truly a ceramic, made from Alumina or aluminum oxide (AL2O3)
Below is a high quality 99.9% silica wick. It is flexible. Not like a clay pot. And it has no plastics and minimal other impurities in it like fiberglass does.
Below is what I think of as fiberglass as in the pink stuff used for insulation.
I would never consider using fiberglass insulation as a wick for an atomizer that is a very bad idea. It is modified for the application of insulation meaning it has other stuff in it and is oriented differently.
But there has been speculation about high quality 99.9% pure silica wick and I have quit using it. There is no study data that I am aware of to support this theory but I will illuminate it anyways. The theory is that the little frays of silica end up being microscopic silica glass javelins that get lodged in the soft tissues of your mouth, throat and lungs. Some fear it could lead to silicosis even though silicosis is known to be caused by silica dust. I guess it depends on the difference between dust created from grinding and cutting versus javelins caused by fraying. Regardless I noticed a lot of fraying while making coils and decided to stay away from it. Some believe that the wet juice will keep the frays in place. But maybe not if you get a dry wick which does happen. I didn’t feel inhaling microscopic spears of glass was a necessarily smart risk.
With that said, there has also been discussion of the safety of using Rayon or Cotton for wick. The theory is it can cause cotton lung disease (brown lung, or byssinosis). And I would opine that if I were burning my wick then I might be concerned about that. But as I don’t burn my wick then I am not concerned. The reason I don’t is because I use temperature protect devices. But let’s say we are stupid. We put a wick in, leave it dry, set our temp limit to 410F and hit the fire button for ten seconds straight. What happens is in the pic below.
Above is the same test with pure VG only the wick is wet, but not saturated and sustained 410F for 10s. I run at 360F for margin.
So what was the point of this test other than to prove if I set out to do something stupid I will succeed? Simple don’t let the wick get dry and use TC at a lower temperature. Dry hits are bad. The taste difference is immediate and bad. Stop vaping and take care of it immediately. And if the wick gets burned, replace it immediately. In fact I assume that if I get a dry hit, the wick is burned and needs immediate replacement.
Lets talk about the build. We will start with what wrong looks like. Notice the build pictured below on a Fogger.
Spread coils are easier to build and with a little gap between the wraps, more vapor is produced than if the coils are squished tightly together in a “contact” coil. That little gap allows more vapor to pour out of the heated wick because of the space between the wraps. However this build was an abysmal failure. First, the gap is too large. Second, the coil is too long. This is not how to do it. When the mod or APV is activated, electricity flows through the atomizer coil creating heat. Heat from the coil is then transferred to the eLiquid in the wick creating vapor, just like steam is created when water is heated. As long as the temperature of the e-Liquid in contact with the heated coil wire stays above the vaporization point and below the cracking point of the eLiquid then only eLiquid vapor is produced. Notice these coils sit directly over the air holes which is good. But the ends of the coils extend past the air holes which is bad. Not only that, but the wick length, the distance juice has to wick to get to the middle of the coil is longer than the coil diameter. The ends of the coil vaporize most of the eLiquid before it has a chance to get to the middle of the coil even though the middle is being fed by both ends. A rule I have learned through trial and error is I do not want the coil length more than twice the diameter of the coil. Also, it is best if the entire coil sits within the extent of the air hole if possible and sits as close to the air hole as possible without shorting out. Sometimes compromises have to be made as this isn’t always possible but we need to think about it a little.
We also need to think about balancing the coil so that as many wraps of a coil get heated at the same time as possible. Coils have a tendency to heat from the center. And especially with multi-coil attys, we have to balance each coil. I find dual coils difficult enough though there are attys out there with 3, 4, and even six or more coils. I suggest this is not a good trend as balancing just two can be tedious.
Consider the image below.
With evenly spaced coils the center wraps are reaching higher temperatures than the outside wraps. By spacing our coils more in the middle than the ends we can even out the temperatures across all wraps. No it won't be perfect but at least the high temperature excursions will be lower.
The more juice we can get to flow without leaking or flooding the better. I will take a flood over a dry hit any day. On a flood, low vacuum inhales and a tad more power and I can vape off the extra juice that flooded into the vaporizing chamber. A flood results in a gurgling sound in the atty during inhale. Too much liquid flow and it starts leaking out the air holes. What I want is a coil and wick build that is right on the verge if not a little on the flood side but does not leak. This will give the cool, dense, flavor packed vape experience I am looking for, minimizes build-up and lessons the risk of burning or cracking the e-Liquid.
The juice channels can be made larger but at a point it will cause flooding (too much juice in vaporization chamber) and leaking (through the air inlet holes). Large juice channels can be prevented from flooding or leaking with the correct wicking approach and that is the best configuration, large juice channels wicked to the verge of flooding but well below leaking. Juice flow is a simple matter of surface area in the juice channel, resistance from wicking material (density and length of travel), viscosity of liquid (including temperature effects from ambient temperature and use of the atty) and vacuum created by draw.
Airflow control (AFC) as shown above on a Squape-R with successive sized holes can be adjusted. On a tank atty, the airflow control determines the amount of vacuum created with a typical draw to help pull juice into the wick and vaporization chamber.
Do not drill out air holes on a tank atty.
If I am getting snap, crackle and pop or dry hits, the problem is the wicking method, not airflow. Drilling out air holes will make it worse not better. In fact if I am getting dry, burnt hits consistently then drilling out air holes makes it worse. Note that reducing the air hole size at any point after the vaporization chamber either has no affect on vaporization chamber vacuum or reduces it. The vacuum is created by a small air hole on the build deck and a larger one through the drip tip.
Atty designs that allow the coil and wick to be positioned directly over the air intake holes in the chamber produce more cloud. This is because the air flowing over the coils increases vapor intermix with the air. Yes the airflow also cools down the coil and wick but not nearly as much as juice flow does. However once power is increased to a point, we start starving the coil and once again are back to a hot, dry vape.
Any given build has an inherent amount of power it can sustain before it starts starving the coil for e-Liquid. So back the power off when this happens. Yes there will be less vapor produced but it won’t be dry or burnt which is dangerous. Then we can start looking for remedies E.G. different build methods, atty modifications or a different atty.
While not as prevalent, it is possible to have too little power depending on the build and atty. In this condition the vape is too cool and doesn’t get close to the set temperature protect on a TC APV. Little vapor is produced and what is produced is too dense. The choices are to increase power, buy a more powerful mod, rebuild to reduce juice flow, or get a different atty.
The size of the wire depends on our target resistance and how many wraps we can make. There are several calculators online that aid in this. I like http://www.steam-engine.org/coil.asp. Remember the coil rules we discussed above. If the air hole is 2mm then we want a coil that is no more than 4mm long. In general, the lower the gauge number, the less resistance for the same length or wire. But the lower the gauge number, the larger the wire diameter and therefore surface area in contact with wick and therefore the more vapor production and power the build can sustain. Also thicker wire has more mass and gets to temperature slower than thinner wire. The preheat function of the DNA-40 and powerful modes of the SX350J mitigates this somewhat but keep in mind that more mass or thicker wire also helps to reduce temperature overshoot. I find 30 gauge a good place to start and will work well on all atomizers while 28 gauge can be used on those attys that can take a slightly larger coil and 26 gauge on those few attys that can support massive coils. And when it comes to Ni200, the thicker gauge wire is easier to work with and attach to the atomizer.
There are two types of coil wraps, the contact or touching and the spaced or spread. I always use spaced, never use contact. Coils heat from the center and the tighter the wraps are, i.e. closer together, the fewer the wraps in the middle get hot and the temperature difference between those and the outer wraps gets greater. Remember that a TC mod doesn't know which wrap from another, it looks at the aggregate resistance change or average temperature of the entire coil. Coils with greater spread in the middle then the ends, have a much more even temperature wrap to wrap. I don't glow my coils red hot to even the wraps out and it is not recommended as we discussed in are eCigarettes safe and Temperature Control.
By spreading the coils more in the middle than the ends we can have more wraps of our coil getting hot and the same time and with less temperature variation between wraps. This makes TC work really well and the build more efficient.
Let us make a simple single wire coil. I’ll use washed and cleaned 30 gauge NI200 and wind 4 wraps at 3mm. Then spread it apart and push it back together. Then attach it as shown below.
When making coils, leave it on the mandrel when attaching. Try to make spaced coils where the wraps aren’t touching each other but are close together. Clip the legs off after screws are tight and remove mandrel. Make sure the coil is not touching the build deck. It should be at least 1 to 2mm away. We will also make a 3mm coil with 8 wraps on the other KF. Start with a piece of Rayon or OC pad. Twist and pinch one end into a point to start through the coil then fold the ears up and stick through the chimney and screw the chimney base on as shown below.
Next trim the wick into a bow-tie just above the chimney base as shown below. Just trim to the top of the chimney base.
Blow on the ends to fluff up the cotton as shown above right. This is not needed for Rayon. Use a small flat blade screwdriver and lightly work the wick down in the chamber between the chimney base and build deck as shown below. You want the wick ends touching the juice channels openings. Don’t press on the coil as this will short the coil out on the build deck. Don’t press on the wick near the coil as this will pull wicking away from the outer wraps.
Wet the wick with a few drops of e-liquid as shown below. Just 3 or 4 drops. Screw the atty on an APV/mod and make sure it is not shorted. On the mod just press the fire button one time. It will read the resistance ~0.15 ohm. Finally screw on the chimney top and reassemble the tank, top and drip tip, fill and vape. Repeat above for the 8 wrap version ~0.27ohm.
Both sustain 4-6W. One might think that twice as many coil wraps would sustain twice as much power. The 8 wrap version has twice the wire and surface area. However, the center wraps get hot first regardless of how many watts are applied and the juice flow remains unchanged as that is dependent on the viscosity, juice port size, wick material and wick length. Doubling power will not develop twice the power under temperature control unless twice the eliquid is delivered by the wick to the coil.
If I tried to vape the 8 wrap build at 8-12W on an APV without temperature protection, I would get dry hits. There simply isn’t enough juice flow with the small juice channels to keep the coil supplied with enough juice to double the power. Stuffing more wick into the chamber between chimney base and build block can be done to stop leaks but typically won’t help that much to deliver more juice to the coil. It will effectively raise the juice channel by providing an elevated juice reservoir and will shorten the wick length to the coil. But it still doesn’t change how much juice that juice channel actually delivers to the coil. For that, we need larger juice channels.
Note cotton can’t be packed tighter or it will not wick as well. There is a fine line with cotton. Packed too thin and it won’t make contact with the wire. Packed too tight and it won’t wick. We need just enough cotton to touch the entire inner surface area of the coil but not packed so tight that it drags on the wraps when we pull the wick through. Rayon on the other hand is easier. If we wick with Rayon I just use enough so I can pull the wick through without distorting the coils. A little drag is ok. The good thing about wicking is, if it doesn’t feel right, pull it out, pull a little off and try again. We can rewick as many times as it takes. I experimented many times by wicking and trying then repeating changing the wick density until I figured this out.
Any of these methods allows the inclusion of a top wick as shown below.
Except with the KF method the top wick just lays over the existing coil/wick and not across it. I have seen this called the “taco” wick or the “mummy” wick. Some will lay a smaller strip some will lay two leaving a gap or simply make a hole on top. I have also seen this in coil cartridges and referred to as a “flavor” wick. I can’t say that it adds much to the power capability. It does some but mostly it helps give a nice cool tasty vape.
I have tried dual coils and vertical coils on KFs. But I find the design of the KF is rather limiting for these methods. There are other attys that excel at those methods.
I have found heat dissipation is key. On a small atty with low juice capacity and a small vaporization chamber I can chain vape it for several puffs sit it down and come back and see the juice level has dropped just sitting there. The eLiquid will literally boil off through the wick as it cools down. Now I didn't see vapor coming out as it is occurs at a low level over a long period of time. Glass conducts heat a lot better than plastic. A glassomizer will dissipate more heat. A larger capacity tank does two things. First, given the same amount of heat from the coil, the temperature of the juice, tank and atty will be lower. Second, to hold more juice, the tank has to be bigger and therefore has more surface area to dissipate the heat. The downside is glass and more juice capacity equates to more weight and physical size.
What separates individual atty performance in the same type in terms of vape experience is the size of the juice channels and the size of the air holes and their position. Larger juice channels will flow more juice. But if the juice channels are spread far apart from each other the wick length can become long. Shorter wick lengths sustain longer draws and better successive chain vape draws. Larger air holes will flow more air and allow for larger coils. More air also has a cooling affect but if the juice vapor is not increased the flavor density suffers and gives a more unrestricted vape experience. So if I run a lot more power with more air flow to maintain flavor density, the amount of vapor may be more than I can handle.
If I see an atty that has large air holes but tiny juice holes, I know it is going to have muted flavor.
If I see an atty that has large juice holes but tiny air holes, I know it’s going to be a flavor machine.
If I see one that has both small air and juice holes then it will take less power and produce less vaporized e-Liquid while giving a restrictive draw.
If I see one with huge air and juice holes, then I know its performance could be awesome if all the other things are there like air flow control to change from cloud to flavor, large chimney and drip tip opening etc.
There are several great RTAs out there. As new ones come out, and they do so on a regular basis, by experimenting and figuring this stuff out, I am now better prepared to evaluate them just by looking at their design. And remember, there are tons of reviews online as well.
And always remember with cotton, less is more. There are other atty discerning factors such as heat dissipation, size of juice and air holes how much e-Liquid it holds and features like ease of filling, adjustable 510 center pin, glass or plastic etc.
And remember high VG juice is thicker and more viscous so just using a thinner e-Liquid can make any atty flow more juice. An e-Liquid with PG in it is thinner than 100%VG. Some flavorings can also thin the juice. Another way to look at it is if we want to run high VG then don’t even bother with attys that have small juice channels and/or tight clearances between chimney and tank wall.
On an atty that doesn’t use a lot of juice, in other words lower power and vapor production, then less e-Liquid capacity is needed. On an atty that has huge juice consumption and sustains a lot of power and produces gobs of vaporized e-Liquid, then a larger tank is needed. In any case, ease of refill is a always a wonderful feature.
I like an atty that holds at least 4ml of e-Liquid. That will usually get me through most of the day. But there are plenty of attys that hold around 10ml and a few that hold 19. Of course they are larger and may look awkward sitting on a small APV. If going all day is the goal, then these should be matched with a 26650, LiPo or dual 18650 APV as I will also need the extra battery capacity.
The rebuildable dripping tank atomizer (RDTA) can give a lot more vapor production and power soaking performance, akin to an RDA or “dripper” for short. The RDTA eliminates the need for constant dripping with a bottle as there is an integrated refillable tank. These are not like the “zero gravity” or Flash-E style RTAs. These are not like the convertible RTAs like the Aqua V2. There are two primary types of RDTAs, the bottom fed squonks and the top fed springers.
I am not sure where the term “squonking” came from, perhaps from the honk sound they can make when squeezing the bottle. Regardless of where it came from, squonking is vaping a bottom fed atomizer. A bottom feed atomizer has a tube running from the wick/build to a squeezable bottle. The first I heard the term was with the REO atomizer/APV where the bottle was in the mod and a tube ran through the bottom connector.
However, there are squonking atomizers that have the bottle integrated into the atty and have a normal 510 connector. These are becoming popular as they are significantly cheaper than a specialized non-TC squonking APV and atty combo. One such atty is the Fountain.
The other type of RDTA is the top fed springer like the Tsunami or Dolphin. These have the tank above the build/vapor chamber and when you press on the top of the atty, it allows juice to drip on the build below.
Just to confuse the whole squonking scene, a new type of squonking atty that uses a spring action pump has been released. This is a bottom fed spring action atty. When you press the top of the atty, it pumps juice up into the vaporization chamber. An example of this type is called the Skyfall.
EHPro released this RDTA around the same time as the Bachelor RTA.
There is a spring in the top cap so that when you press down on the top cap it squirts juice in the bottom build chamber. This is a spring action squonker or RDTA. Below is what the build deck looks like.
The build deck looks like any RDA build deck. And top right shows a series dual coil 24gauge Ni200 build with Rayon wicks. The wick ends drop into the juice cups and get saturated with e-Liquid as it rains down from above.
Also in the top cap of the eTank F1 is the airflow control. Air flows down a tube around the chimney and inside the tank to the lower build deck then vapor comes up through the chimney. This makes for a cool vape. I really like this design and the F1 with that build is sustaining 40W 2 360F with 100VG. Very typical for an RDA but more like a tank so you don’t have to drip form a dripper bottle all the time just press the top cap down to squonk some juice into the build below.
The secret to rebuilding any cartridge coil is to figure out how to get it apart. The coils and wicks are small. But given my fat fingers and over the hill eyesight, if I can do it anybody can. A pair of magnifier glasses also helps.
Let us take apart an Aspire BVC cartridge for a Nautilus mini that I use on my Guardian II e-Pipe. I pick this one because it is difficult being small and the first I know of (others followed) to use a man-made mineral fiber (MMMF) in the wick (microscopic mulched up glass fibers). And this stuff is very crumbly. As long as it stays wet it is probably fine. But I don’t like it. It is even worse to me than silica rope.
We start by taking the end plug out by using a coil jig or small screwdriver that will fit in the airhole and pull it out like a t-wrench. That is the positive post in the atomizer and makes contact with the 510 center pin. We locate where the cartridge is joined, in this case right at the base as shown below.
We get a good grip and use an old pair of flush cutters right at the joint to clamp wobble and pull it apart as shown below.
Once apart we unravel it layer by layer and end up with what you see below. The two clam shells are the Man Made Material Fiber (MMMF). We will replace it with OC cotton.
As you can see above there is a very small screen with a hole in the center inside the cartridge casing. Many have wondered why it is there. It serves two purposes, primarily as end stop for inserting the coil and wick and to keep the wick and crumbly stuff inside on high vacuum draws. We can see what happens to the crumbly stuff when I squeeze it with my fingers below.
The coil is made of a piece of nonresistance (NR) wire welded to resistance wire (R) welded to another piece of NR wire. The NR wires are the legs and the R wire is the coil heating element. It is possible to purchase or build your own small gauge wire welder. I find it doesn’t matter much and just use whatever wire I need for my mod for the whole assembly, legs and coil, whether that is Kanthal or Ni200. So we will wrap our own coil on a 2.5mm mandrel. Sandwich the coil with KGD. Insert that into the metal sleeve with KGD ears sticking out through the slots of the metal sleeve, trim the KGD to the sides of the sleeve with flush cutters, insert insulator with one leg outside (top coil leg) and the other inside (bottom coil leg) then install pin.
Here is a comparison of this cartridge coil shown below in the middle.
To the left is a Delta II cartridge with juice control. To the right is the BVC cartridge used in the Melo/Atlantis. The larger diameter makes rebuilding a cartridge coil a lot easier.
Let us rebuild the Atlantis coil cartridge which is easier to take a part.
Simply pull the bottom pin, pull the insulator, grab the coil legs and pull both at the same time. In general we will make a coil, rewrap the coil with wick and reinsert the build, insulator and pin. As always one leg outside the wick and insulator and one leg inside. You will see how it goes when you take it apart. You make the coil on a 4mm mandrel. Alternatively you can take the metal sleeve out by putting a rod or socket of the right diameter in the top and while hold the cartridge body with a pair of pliers, tap the sleeve out with a hammer. Shown below, the long ribbed drip tip top fits perfectly for this purpose. Lightly tap the bottom of the drip tip with the hammer. The sleeve will pop out. Don’t squeeze the body with the pliers too tight as it will crush it. The bodies are thin wall brass with chrome plating. Just position the pliers so the jaws catch the top lip of the cartridge.
Now the paper sleeve can be removed and the whole assembly rebuilt with just KGD as shown below.
Wrap KGD around the coil then insert that into the sleeve with an ear hanging out, trim that ear off with flush cutters flush to the side of the sleeve, insert into the cartridge. Push the coil build down until the build is about a 1/8th inch from the bottom of the cartridge. Then reinstall insulator and pin. Although it is not needed, you can add a roll of KGD to the top of the coil assembly and/or put the screen back in as shown above right. Finally use pliers to squeeze the sleeve back into the cartridge as shown below.
Be sure not to damage the top rim of the cartridge. Use a thin piece of wood if necessary, like a tongue depressor between the plier jaw and the cartridge rim to prevent marring and crushing of the cartridge rim. The cartridge barrels or bodies are usually soft and made from chrome or nickel plated brass.
Instead of wrapping the coil sandwich it between two pieces of KGD so that four ears are sticking out the sleeve slots shown below. Then flush cut the ears to the sides.
All the information contained in these pages are only the opinions of the author and the author is not an expert at anything.