The 101 on Mech Mods.

How to choose and use a mechanical mod and an RDA. 

Nathan Upchurch
Jun 3, 2014 · 11 min read

You’ve watched the YouTube videos, seen the clouds, and heard people raving about the flavour you can only get with a “mech mod” and a “dripper.” It all sounds great, but it’s so complicated, right? Wrong. I’m going to tell you everything you need to know, from what a mech mod is, how to choose a setup, how a mech mod works and how to use it, and we’ll finish off with a bonus video from GrimmGreen. Ready to get started? Here we go.

What is a mech mod?

A mech mod is basically just a metal tube with a switch. All it does is connect your battery to your atomiser when you hit the switch. That’s it. The difference between a mech mod and a VV (variable voltage) device, like an iTaste, or an Ego Twist, is that it has no circuitry or electronics. The advantage to this is that you can set-up your vape to perform just how you like it with no limitations imposed by a chip. If you want a walloping throat-hit, great plumes of vapour, and top notch flavour, you can make it happen without the limitations of a VV device.

What is an RDA?

An RDA is an atomiser. Specifically, a Rebuildable Dripping Atomiser, also known as a “dripper.” The function of an RDA is to route electricity from your battery through one or more “coils” of resistance wire, that most commonly look like little springs. Fans of RDAs, like myself, will tell you that they deliver the best flavour and vapour production you’ll get out of your vape, providing you build your coils right. With an RDA, you’ll build, or “wrap” your own coils, and fill or wrap them with a wick, most commonly made out of cotton. An RDA will have no tank, meaning that you’ll need to drip your e-juice on top of the wick as you go.

What do I need to get started?

To get started, you’ll need a mod, an RDA, an ohm meter, a charger with voltage display, a battery, some resistance wire, some cotton balls, some tiny wire cutters and a pair of tweezers. If your RDA doesn't come with one, get a drip tip as well. Oh, and of course you’ll need some e-juice / e-liquid. Don’t go buying anything just yet, I'm going to walk you through this.

Choosing a mod.

When choosing a mod, look for three things: a locking mechanism, vent holes, and good reviews. A good mod should have some kind of lock in place to make sure that it doesn't fire up when you don’t want it to. For example, I have a Nemesis clone, which has a ring above the fire button that screws down making it impossible to press the button accidentally. This is important because those coils get HOT. Leave them running for a long enough time, and they’ll start fires, burn out and kill your battery, and cause all kinds of havoc. That’s one lesson you don’t want to find out the hard way. Vent holes are important because if a battery goes bad, or vents, it releases hot gas. If the gas has nowhere to go, bad things happen. It’s as simple as that. Finally, make sure that your mod gets good, genuine reviews. Watch some videos, read the comments. A mech mod will last for years, and they aren't exactly cheap, so make sure that you’re buying one that you’ll be happy to have around for some time. Besides that, it’s all aesthetics. There are all kinds of beautiful mods available, so have a good look around.

Choosing an RDA.

When choosing an RDA, there’s so much variety available that it can be daunting. When choosing an RDA, I look for three things in particular: adjustable airflow, dual-coil capability, and (again) good reviews. Adjustable air-flow just means that you’re able to choose how much air gets through the RDA, over the coils, and into your lungs. Generally, higher airflow = more vapour, and lower airflow = more flavour. The lower the resistance of your coils, the more airflow you’ll need, so if you’re going to be experimenting with different coil builds, it’s great to be able to tinker with your airflow too. Dual coil capability just means that there are three posts inside the RDA, making it easier to run two coils at once. When you run two identical coils parallel to each other, the resistance is cut in half. This allows you to get more vapour without fiddling with super tiny coils. You may never run two coils at once, and that’s totally okay. It’ll still run a single coil just fine, and with that handy adjustable airflow feature, you’ll be able to adjust the RDA to suit your build, while maintaining the option to get adventurous. Finally, look for an RDA that people like and review well. Go and watch Grimm Green and Rip Trippers on YouTube. Find out what people like and why, and you’ll be able to make a better informed decision. Personally, I use an Omega clone.

What’s a clone? Should I get one?

A clone is a cheaper re-make of a mod of RDA. You generally get what you pay for; some clones are great and some are terrible. The key to buying a clone is to read plenty of reviews. Find out what people think of the build quality and performance. Ethically, many people take issue with buying clones in the first place, as they essentially rip off the hard work of someone else, usually an artisanal mod / RDA maker who is trying to make a living. I tend to agree, but I also can’t afford to spend $100 — $250 on a mod plus $50 — £150 on an RDA. If I could, I would; for now I opt for the clones, which sell for a fraction of the price. You should do whatever suits you.

Choosing a battery.

The battery, along with the charger, is one of two things you should never cheap out on in the world of mech-mods. The most important factor when choosing a battery is the amp limit. Get a battery with no less than a twenty-amp limit. The lower the resistance in your coils, the more amps you’re going to draw from your battery. Over-stressing a cheap battery can cause venting, which brings me to another issue: protected batteries vs non-protected (IMR) batteries. Protected batteries (Lithium Ion) have a bit of circuitry in them that is designed to shut them off if anything goes wrong. The problem here is that if something does go wrong, and the circuitry fails, protected batteries vent violently, with flames and / or explosions. Non-protected batteries (IMR / Lithium Manganese) don’t have this safeguard, but when they vent, they do little more than get awfully hot. As a result, I go with the IMR batteries, but that’s just a personal choice. Besides that, the other thing to consider in a battery is mAh (Milliamp Hours). With mAh, the bigger the number, the longer the battery lasts. Make sure that your battery will fit into your mod before buying it. For most mods, an 18650 battery will do. I use an MNKE 18650 IMR in my mod.

Choosing a charger.

When choosing a charger, make sure that it’s designed to work with the type of battery that you've bought. Also be sure that it has an LED display showing you the voltage of the battery to avoid over-charging. A good charger will be able to accommodate multiple battery sizes, have an LED display with voltage readout, and have overcharge protection. When you buy the battery, the site should tell you what the maximum / minimum voltage should be for the battery. Follow this religiously to avoid damage to the battery, reduced battery life, and venting. I use an LUC by Efest, and it seems to do the trick.

Choosing cotton, wire, and an ohm meter.

The cotton is going to function as your wick, so try and buy good stuff. Most vapers prefer organic, unbleached cotton. A bag of cotton balls is super affordable, and it’ll last forever, so don’t cheap out. When you’re first starting out, you don’t need to worry about your wire. Just pick up a spool of 28 gauge annealed Kanthal. I bought a 50 foot spool for around $6 a few months ago, and I’m not nearly finished. If you want to get fancy with your wire later, that’s cool too. Some people prefer nichrome, some like to build with ribbon wire, and some like to buy lower or higher gauge wire to affect the resistance of the coil. I can’t be bothered personally, and I have great success with plain old 28 gauge Kanthal. Choosing an ohm meter doesn’t have to be difficult either, I’ve got a plain old Sigelei ohm meter that works well. I did have to file the threaded section down ever so slightly to ensure that my RDA made a connection, but it wasn’t a big deal. While it’s not so important which ohm meter you choose, it’s very important that you do have one. In order to know if you’re going to be over-stressing your battery, you need a reliable way to test the resistance of your coils. An ohm meter is the easiest way to do this.

Choosing an e-liquid.

Remember that when you’re using a mech mod and an RDA, flavour is going to be more pronounced, and vapour is going to be hotter and more voluminous. With that in mind, avoid that tempting little “add extra flavour” button when you’re buying your juice. Stick with low-nicotine juice too. I vape six mg/ml. Maybe you can handle eight mg/ml. Maybe. Any more than that and you’d better be a masochist with a penchant for coughing fits. This device is going to hit HARD, and too much nicotine will not feel pleasant. I used to vape eighteen mg/ml in my basic tank setup, but I learned the hard way that the same amount of nicotine is way too much on a mech / RDA. I always go for 100% VG juice too, because it has less throat-hit (which you don’t need any help with on an RDA) and it produces more vapour. You’re going to go through a lot more juice on an RDA than you would with a tank, so remember that when you’re buying. If you want, you can easily make your own at home, but that’s another article.

Okay, we've got our kit. Science time!

Ever heard of ohms law? Well you’re going to need to know it in a minute. Basically, using ohms law, we can use the resistance of our coil(s) (which we can read from our trusty ohm meter) and the voltage of our battery (generally 4.2 when freshly charged) to calculate the amps drawn from the battery. It takes ten seconds to work out onm a piece of paper, and two seconds to type into an ohms law calculator, which you can find online or as an app on your phone. Divide your battery voltage by the resistance of your coils, and you’ll get your amps. If your amps aren’t at least slightly below the amp limit of your battery, you’re risking ruining your battery and causing bad things to happen. If you bought a good battery like I told you to, this shouldn’t be a problem unless your coils are ridiculous. I’m running a .4 ohm dual-coil set-up on a freshly charged 4.2 volt battery. That brings my amps to a perfectly safe 10.5, as I have a 25 amp limit on my battery. Hence, I can vape all day with no fear of losing my lower jaw.

Let’s get set-up.

Okay, now that you have everything and know a little safety info, let’s start building. Find something small and round, like a tiny screw-driver, and wrap your resistance wire into a neat little spring. I use a blunt-needle syringe, and I do eight wraps around it. Be as tidy as possible when you’re wrapping. After that’s done, make an identical coil if you’re building a dual coil set-up (like I do), and put the coil into your RDA. This will usually either involve unscrewing the little screws on top of your RDA posts and inserting the leads into two little holes, one in the positive lead, and another in the negative, or wrapping the wire-leads around the screws before tightening them back up again. When you’re tightening your screws, take care not to be too zealous, snapping your wire-leads with the pressure of over-tightened screws. The coils should not touch the posts, well, cap, or any part of anything. That’s in bold for a reason; you don’t want a short, do you? Nope. Put the coils just next to the air-holes as well, for maximum vaping pleasure. Once the coils are installed, (ensuring lead-length is identical for dual-coil builds) clip off the leads, and screw your RDA onto your ohm meter. Do the math. Good? Sweet. Screw the RDA onto the top of your mod, making sure that the connecting pin makes good contact with the bottom connector of the RDA. Check your battery (oh, and charge it too). Is it clean, with the wrapper free of scratches, etc? If so, go ahead and slap it in your mech mod, positive side up, making sure not to over-tighten anything, and ensure that the battery makes good contact with the top pin, and the bottom pin, when the button is depressed. Screw the RDA on top of your mech mod and fire it up for a second. If everything is making a connection, the coils should glow. Both coils should glow at the same time in a dual-coil build. If they don’t, something is uneven. Fix it. Your coil(s) should glow evenly, from the inside out. If they don’t, pulse the fire button once and squeeze them together with a pair of tweezers. Never fire the mod while you’re touching the coils with anything. Keep at it until they glow evenly, from the centre out. Got it? Nice one. Tear off a tiny bit of cotton, and roll (not twist) it into a little wick. pull it through the coil, and make sure that at least one end dips down onto the floor of the RDA. Don’t overload the coils with cotton, a tiny amount will do. Load the wick up with juice (enough to soak the wick, not fill the well at the bottom of the RDA. You don’t want it flooded), and fire. It should sputter and steam. Success. Put the top cap and drip tip onto your RDA.

Vape away!

Alright, that’s you. Some advice: Don’t let the battery get too low. When performance starts to die down, charge it up as soon as possible. Keeping your batteries under-full for a long time, or letting them get too low can damage them. Always lock your mod when it’s not in use. If you don’t, you might just wind up winning a Darwin Award. Please be considerate when vaping around others. “Vapeholes” ruin it for the rest of us. Make sure that your wick is always nice and wet. Cotton burns when it’s dry… a dry hit on a cotton wick is not pleasant. Take lung-hits on your RDA for max vapour. I know all of this sounds very complicated, but really, the bulk of what you’re doing is making tiny little springs. It’s a little bit of a learning curve, but it’s not difficult and it’s definitely worth it. Watch some YouTube videos of experienced vapers building on their RDAs. This is hard to take in via text, I know, but it all makes sense when you see it in action. Hop onto and ask some questions. The community will be delighted to help; they’ve helped me plenty. Have fun, blow clouds, and be safe!

Bonus video.

Watch GrimmGreen’s video on moving to mods.

    Nathan Upchurch

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