Building coils - understanding coils and wire winding

A coil is a heating element wound around a wire, which is installed in a rebuildable atomiser (RDA, RTA or RDTA). The wire coil is packed with cotton, which absorbs the e-liquid from the tank or deck. When current flows from the mod through the coil, the wire heats up, the e-liquid vaporises, and you inhale the resulting vapour.

The key factor is the electrical resistance, measured in ohms (Ω). This is determined by the wire material, wire diameter, number of turns and the inner diameter of the coil. Typical values range from 0.15 Ω (sub-ohm, high power) to 1.2 Ω (mouth-to-lung, low power). A distinction must be made between self-built coils and pre-made coils: in the latter case, the coil is already housed in a replaceable head and does not need to be built yourself.

The principle is simple: electricity generates heat, heat vaporises e-liquid. The art lies in fine-tuning. Depending on your goal, you vary the material, diameter and structure of the wire coil.

Typical coil types

• Round Wire (standard coil): Simple round wire, usually Kanthal A1 or SS316L. Ideal for beginners, robust and forgiving when building coils.
• Clapton coil: A thin wire is wrapped around a thicker core wire. More surface area, more intense flavour, longer heat-up time.
• Fused Clapton: Two or more core wires in parallel, wrapped with thin wire. Even more surface area, balanced flavour.
• Alien, Staggered Fused Clapton, Framed Staple: Complex winding styles for experienced builders with a focus on flavour and aesthetics.

In everyday use, a mouth-to-lung vaper often uses a simple round-wire coil at 0.8–1.2 Ω and 12–18 watts. Direct-lung enthusiasts with sub-ohm setups tend to prefer Fused Claptons at 0.2–0.4 Ω and 45–80 watts. Nicotine salt e-liquids tend to suit the first category, whilst classic bases with low nicotine content suit the second.

A clean coil build isn’t rocket science, but it does require care. Safety comes first – incorrect resistances can overload batteries.

• Use an ohmmeter: Measure each coil with a separate ohmmeter or your mod’s built-in measurement mode before firing. This allows you to spot short circuits immediately.
• Check battery capacity: Your battery’s maximum discharge current (CDR) must match the resistance. Rule of thumb: at 0.2 Ω and 4.2 V, around 21 A flows – not every 18650 battery can handle that.
• Choose the right wire material: Kanthal and SS316L for power mode, Ni200 or titanium exclusively for temperature control. Never use Ni or Ti in pure power mode.
• Use the right amount of cotton: too much cotton slows the e-liquid flow; too little leads to a burnt taste. The cotton should slide through the coil with slight resistance.
• Wind the coils evenly: Wind the coils tightly and in parallel, then align them with ceramic tweezers whilst they are glowing. Uneven coils create hotspots.
• Pay attention to the position in the deck: The coil should be centred in relation to the airflow so that the airflow cools the wire optimally and carries the vapour.

A typical beginner’s mistake: using wire that is too thin combined with a high wattage. This results in burnt-out coils and charred cotton. It’s better to start with 0.28 mm Kanthal A1, 6–7 turns on a 3 mm inner diameter, and work your way up to the power setting.

How often do I need to change a coil?

Depending on the e-liquid and usage, a well-built coil will last 1–3 weeks. Sweet e-liquids with a high proportion of sweeteners significantly shorten the lifespan, as residues stick to the wire.

Do I need special tools for coil building?

We recommend a winding rod of the appropriate diameter, ceramic tweezers, side cutters, a small screwdriver and an ohmmeter. Complete sets containing all the parts are available for under 40 francs.

Which coil types are suitable for beginners?

Simple round-wire builds using Kanthal A1 are ideal. They are affordable, dimensionally stable and forgiving of minor mistakes when winding. Clapton or Alien coils are only worth trying once you’ve mastered the basic technique.

Is building your own coils cheaper than buying pre-made ones?

Significantly. A metre of Kanthal wire costs just a few francs and is enough for around 20 coils. Pre-made coils cost several times that per piece. With a bit of practice, each coil takes 5–10 minutes to make.

A neat build improves flavour, vapour and cost in equal measure – provided you take a structured approach and prioritise safety. With a bit of practice, you’ll master round wire, Clapton and, later, more complex build styles. If you prefer ready-made solutions or are looking for replacements for your pod system, you’ll find suitable models in our selection of coils and atomiser heads. If you want to build your own coils, you’ll find wire, cotton and tools for your next coil build in our range of accessories.