Everything You Need to Know About Coils for Vaping
Coils are central to your vaping experience. They turn your e-liquid into vapor and are one of the main running costs for any vaper. But if you’re new to vaping, it can feel like there’s a lot to learn about coils, including the different types available, what different materials are used in making coils, and how all of this affects your vaping experience. This post covers all of this, as well as the basics of building your own coils and buying pre-made coils for your tanks.
What Are Coils? The Basics
The coil in your vaping device is a section of wire wound into the shape of a coil that gets hot when an electrical current runs through it. The coil heats up because it resists the flow of current, and that resistance generates heat as a sort of “waste” energy. This is the energy that goes to your e-juice and vaporizes it. So the characteristics of the coil – most notably the resistance but also how it heats up – are absolutely crucial to the process of vaping.
Common Coil Materials
Most coils are made out of one of a few different materials, which depends on the intended use of the coil. Most coils are made from kanthal, but other materials such as nichrome, titanium, stainless steel and nickel are also common.
Kanthal is the most common material used in e-cigarette coils, and it’s solely used for variable wattage or variable voltage (VV/VW) vaping. It’s a mixture of iron, chromium and aluminum, and it can withstand really high temperatures, which makes it a fantastic choice for vaping. The resistance of kanthal doesn’t change much when the temperature increases, which means a kanthal coil will perform reliably across a wide range of wattages. This also means that it isn’t suitable for temperature control vaping.
Kanthal is easy to work with if you’re building coils, and is generally sturdy while still being easy to manipulate. Coils made from kanthal will work with any vaping device on the market.
Nichrome (technically Nichrome 80) isn’t used as frequently as kanthal, but it was common in the early days of vaping. It’s a mixture of nickel and chromium, and like kanthal it is used in VV/VW vaping. The material doesn’t change in resistance very much when the temperature increases, which again makes it very reliable for ordinary vaping but unsuitable for temperature control vaping. Nichrome doesn’t stand up to heat quite as well as kanthal, but both can support temperatures well beyond what vapers will reach. However, nichrome is a little harder to work with than kanthal and that’s why it has fallen out of favor with vapers.
Nickel wire (Ni200) is a very pure nickel blend of wire (99.6% nickel) used for temperature control (TC) vaping. The wire is used for TC vaping because it’s resistance changes more than kanthal or nichrome when heated up, so TC mods can detect these changes and use it to infer the temperature of the coil. This allows your mod to limit the maximum temperature of your coil and thereby work in TC mode. This is the most common TC wire, but it is challenging to work with because it is very flexible and brittle. Setting up wicking with nickel wire is also quite challenging.
Nickel has a very low resistance per inch, though, so coils made from it will tend to come out at a very low number of ohms. This is why you can’t use nickel wire in VV/VW mode.
Titanium wire is another option commonly used for TC vaping, preferable to Ni200 for people building their own coils because it’s much stronger than nickel wire. It has about twice as much resistance per inch than nickel, which makes it a better material for many purposes, but there are some downsides too. If you dry-fire your coil (i.e. press the fire button without a wick or coil inserted), it can get hot enough to form titanium dioxide, which is harmful to your health if inhaled regularly. The best advice is to avoid dry-firing your coil if you’re working with titanium (although this is best avoided anyway). Titanium resistance wire is also fairly expensive to buy.
Stainless steel (a chromium, nickel and carbon alloy) is the most versatile wire type on the market because it can be used in both TC and VV/VW modes. The material changes in resistance enough with temperature to register on most TC mods (although some don’t support it), but the resistance is usually high enough to be used with VV/VW devices. Stainless steel is also easier to work with than both titanium and nickel, and is more affordable too. Stainless steel 316L is the most commonly-used grade, but other grades can be used too. If your TC mod has an adjustable TCR feature (which tells the device how much the resistance changes with temperature), you’ll be able to set it up to work in TC mode with any grade of stainless steel, although 316L is still standard.
Wire Gauges Explained
After the materials, the next most important piece of information for a rebuilder is the “gauge” of the wire. This is simply a measure of how thick the wire is. A wire with a higher American Wire Gauge (AWG) number is thinner, and one with a lower AWG number is thicker. Thicker wire has less resistance per inch than thinner wire. You can understand this by thinking about a pipe with water flowing through it: the water will be able to flow much more easily in a wider diameter pipe than a thinner diameter one. This is exactly the same for electrical current through resistance wire.
To illustrate, here are the values for resistance per inch for different gauges of kanthal:
24 AWG = 0.17 ohms/inch
26 AWG = 0.28 ohms/inch
28 AWG = 0.44 ohms/inch
30 AWG = 0.70 ohms/inch
32 AWG = 1.09 ohms/inch
34 AWG = 1.76 ohms/inch
For builders looking for sub ohm coils, the highest AWG you should realistically consider is 28 AWG, but 26 or 24 are the best options.
Different Types of Coil Used in Vaping
As well as different wire materials and different gauges of wire, there are many different types of coil commonly used in vaping devices. There are so many different options for rebuilders that covering them all would require a whole post on its own, but here are the most common ones you might find in a pre-made atomizer head.
- Standard coils: Ordinary coils are horizontally oriented and made from basic kanthal wire. The simplest type of coil has wraps which don’t touch each other, but all of the wraps touch in “contact” coils and these are broadly similar. The wick is inserted through the center of the coil in most cases.
- Vertical coils: These are like standard coils but oriented vertically rather than horizontally, and the wick is often wrapped around the outside instead of inserted through the center. These are widely used in pre-built coil heads, and offer great wicking and generally improved airflow too.
- Dual/triple/quadruple coils: The simplest way to improve a setup is to use multiple coils instead of just one, so dual, triple, quadruple and so on are just terms for numerous coils in one setup. This reduces the resistance of the setup, reducing ramp-up time and making higher wattages possible.
- Parallel coils: Parallel coils are dual coils, except with two strands wrapped together in parallel rather than separately. This offers the same benefits as dual coils but one wick can be used for both and setup is easier.
- Clapton coils: These are like standard coils but made with the unique “Clapton” wire, which looks a lot like the wire on a guitar string. The wire is composed of a thicker, central core with thinner wire wrapped around it. This produces a much greater surface area, increasing vapor production and flavor, but it does have a bigger “ramp up” time (from pressing the fire button to the coil getting hot) than more simple coil types.
- Twisted coils: Like Clapton coils, these are essentially the same as standard coils but using more complicated wire. In this case, the wires are twisted together so you essentially get two strands in one. This again improves vapor production and flavor, but does increase ramp-up time too.
- Tiger coils: Tiger coils are similar to Clapton coils in that an inner core is surrounded by more wire to create a unique build. In this case, the outer wrapping uses kanthal ribbon, which is flat. This gives the coil a striped appearance and boosts surface area, providing great flavor in particular but also solid vapor production.
Really there are many other types of vaping coil, but this gives you an idea of the sort of thing you’re likely to encounter.
Pre-Made Coils in Tanks: A Brief Introduction
Most vapers use sub ohm tanks or higher-resistance clearomizers with replaceable, pre-made coils. The benefit of this is that it’s really easy to get something good, especially if you know the basics of the types of coils from the previous section. Most of the time, pre-made coils (which come in “atomizer heads”) will use kanthal and will be a fairly straightforward design, such as dual vertical coils. However, in some cases you will find Clapton coils or other different wire types.
For most vapers, the main thing to consider when you’re looking for pre-made coils is the material the coil is made of, the resistance and the suggested wattage range. The coil material is important because you need a specific type (Ni200, titanium or stainless steel) to vape in TC mode. Generally speaking, a lower resistance coil will heat up quicker and produce more vapor, but you need to ensure the resistance is above the minimum supported by your device. Finally, the wattage range will give you an idea of what type of coil it is: coils that run at lower wattages are usually higher resistance and tend to work better for mouth-to-lung inhales (preferred by smokers and recent switchers to vaping), while lower-resistance coils designed for higher wattages are likely to be better for direct-to-lung inhales.
Aside from that, all you have to do is make sure that you get a coil compatible with your tank. Often, the coils will be specific to the tank, but in some cases there is some cross-compatibility for tanks from the same manufacturer. You’ll have to check your coil is compatible with your tank before you buy though.
Building Your Own Coils: A Brief Introduction
Building your own coils is a lot more hands-on than using pre-made atomizer heads, but a lot more affordable too. Aside from a more detailed look at how to build a coil for an RDA (which we have here), you don’t need to know too much to get set up with building your own coils.
The first thing you have to do is choose a type of wire, and the common coil materials and wire gauge sections tell you everything you need to know there. If you’re building a TC coil, stainless steel is probably the best choice for a rebuilder (although titanium is easy to work with too), and otherwise kanthal is preferred because it’s more common and works well in VV/VW mode. You can also buy Clapton wire and other more complicated types in spools too. For wicks, you can use a wide range of materials, but most vapers these days use cotton and it’s really affordable.
Although you’ll save money in the long run, you’ll also need a suitable atomizer (an RDA or RTA – rebuildable drippers and tanks, respectively) and some basic tools to get started. Making your coil involves wrapping it into shape and attaching either end to a post on your atomizer, and you’ll need a compatible tool to connect it up. Normally this is a mini flat-head screwdriver, but most atomizers will come with something suitable. Some wire cutters and a screwdriver or drill bit to use as a “guide” when wrapping your coil are very useful too. When your coil is made and connected, check its resistance using a mod or any other ohm meter before trying to fire it. Never build a coil and try to fire it on a mechanical mod without checking it first.
If you have all of this equipment and know the basics of how to build, it’s much easier than you might expect. It might take a bit of practice to get your coils right at first, and this is really something for longer-term vapers than new switchers, but it is worth it in the long run for the great performance and low running cost.
The basics of coils are easy to pick up, and the information in this blog post can take you a long way. Knowing about the major wire types tells you which ones to use in which situations, and understanding the types of coil available is really useful when choosing pre-made coils for your tanks or choosing what to build. There may be plenty of areas where vapers will disagree – whether a vertical coil produces better flavor than a horizontal one, for instance – but the information you’ve picked up will set you off on your vaping journey so you can try out the options and find what works best for you.