A mechanical mod's chassis, or the main body, may appear to be the most passive part of the entire device, but far from it, especially in tube-style mechanical mods. In tube mechs, the chassis is what carries electricity as it leaves the atomizer—if this pathway is impeded or throttled by unnecessary resistance, the whole circuit is slowed down, leading to a reduced maximum voltage from that mech mod.
This is why it's a generally not a good idea to have a mech mod that uses multiple materials in its chassis. The separated pieces will add extra resistance to your device, even if they're welded together. For maximum performance, it's always best to get a mechanical mod that uses only one solid type of material in its chassis and has only one set of threading connecting the chassis together.
But what kind of material will leave you the most satisfied? That depends on you! Each material has its own unique set of pros and cons that accentuate or attenuate different aspects of performance and durability, so read on to find the best type of metal for you!
Silver is the ideal mechanical mod material. Of all the commercially common metals, it has superior conductivity and superb hardness that is perfectly suited for the 510 threads and positive pins. The only reason we aren't all walking around with solid silver mech mods is because it's crazy expensive! Because of this, you'll most often find mech mods with solid silver contacts, such as shown above in the Nimbus Mech Mod—it's a great way to put silver where it counts without costing an arm and a leg.
The unreal price of silver seriously restricts the ubiquity of solid silver mech mods, but that doesn't stop some mod collector's from picking up one for some seriously flashy cash for the low, low price of $400+. You can also pick up aftermarket components for your mech mod that have been plated in silver or crafted from it entirely to boost your device's performance even further—these are available either from the original manufacturer or from other 3rd party sources, just make sure you pick up the right part for your specific mech mod!
Copper, on the other hand, is a very commonplace material for mechanical mods as well as other types of APVs. Copper is one of the most conductive natural materials in existence, lending to its use in a wide range of applications such as electrical wiring, cookware, motors, heating, and so much more. This is all in spite of copper's tendency to tarnish over time, garnering a dull green patina not unlike that found covering the Statue of Liberty. Nevertheless, copper's corrosion resistance is one of its top reason for use—second only to its excellent conductivity.
Copper is relatively soft compared to other common mech mod materials, so take extra care when carrying around your new toy—or better yet, just pick a different material for your daily beat-around device. Copper is also generally a little more expensive compared to other types of materials, so be prepared to fork over ~$20 extra for your new competition-winner. This increase in price goes up as the purity of the copper increases, but increases in purity are hardly worth the extra cost: above 99% purity and outside of cryogenic temperatures, any advantages in conductivity one copper blend has over another is negligible.
C110 Copper is the most common form of pure copper at 99.95% Cu, but because of its difficult machinability, it's rarely chosen for our vaping needs. Instead, its cousin C145 Tellurium is much harder and more durable, making it common for devices like mech mods and RDAs despite a meager 99.9% Cu purity. C101 Copper—also called Oxygen-Free Copper—is the most advanced and the most expensive, but with a purity of 99.99%, some mech modders believe it's worth the price.
Of all the possible mech mod materials, aluminum is by far the lightest as well as the cheapest. Aluminum is a marvelous material responsible for making many of your favorite things possible, such as soda cans, bikes, cars, and even aerospace tech! And now you can have a little piece of that special stuff on hand every time you vape!
Surprisingly to some, aluminum has excellent conductivity—falling just below silver and copper. It's also relatively cheap, making it a great choice for your next beat-around mech. Just be careful: aluminum is one of the softer metals. Not as soft as copper, per se, but just don't go chucking it against walls or anything.
Known best for its distinctly golden color, brass is definitely gaining popularity alongside copper as the go-to mechanical mod material. Made of a varying blend of copper, zinc, and sometimes tin, brass comes in many different alloys. 464 Naval Brass—the most common type for vaping applications—has a 60%:40% Cu:Zn blend.
Brass also tends to tarnish over time, but it's still just as manageable as copper. Brass' conductivity, however, falls below silver, copper, aluminum, and gold on the conductivity totem pole—pretty low for one of the top choices in metal. Brass offsets this lack of electrical magnetism with the fact that it's one of the hardest metals available, offering durability and longevity in place of instantaneous power.
And last but not least, stainless steel—one of the most ubiquitous metals on the face of the planet—needs no introduction. This highly durable, low maintenance, extremely tough material is a top choice for almost any application available. But this isn't enough to work around the fact that steel has terrible conductivity! In fact, it's one of the worst materials available for conducting electricity. However, this is generally unnoticeable by noobies to mechanical mods—bless their poor hearts—but advanced vapers will tell you that installing a build lower than 0.3ohm will cause a hot button, or excess electrical arcing that makes the firing switch heat up suddenly.
Stainless steel is available in a number of grades, such as 304, 316, and 316L. 304—also known as A2 stainless—is the most commonly chosen chassis material for stainless steel tubes mods as well as smaller vape devices like RDAs and sub-ohm clearomizers. 316 and 316L—also called A4 stainless—is another popular choice chosen specifically for its increased resistance to corrosion; 316L is especially popular as a coil heating element, thanks to the low-carbon content endowing it with improved resistance degradation under high temperature.
While it can be expensive to make a mechanical mod component entirely out of a costly material like gold or silver, metal plating is an easy way to add an extra dose of protection- and/or performance-boosting coverage.
Gold, Nickel, & Rhodium
Gold, rhodium, and nickel plating are some of the top choices for protective finishes over crucial components like positive pins, threads, and battery contacts. These are all remarkably resistant to corrosion damage, so they're often placed in a thin layer over electrically active parts made from a material that's prone to tarnish, such as solid copper or brass. A tarnish-resistant plating provides a clean, polished metal surface for electricity to flow as freely as possible.
Silver plating is used in a similar manner, but as opposed to providing protection, silver provides supreme conductivity to any material, making it an easy way to completely break your opponents' will to compete without having to break the bank.
Cerakote is often chosen by manufacturers as a final protective finish in addition to adding a splash of color to mechanical mods as well as other heavy-duty equipment such as firearms and EDC accessories. Much more resilient than mere paint or anodizing, Cerakote is a high quality colored polymer-ceramic coating that adds significant protection against corrosion, abrasions, skips, chips, bumps, bruises, and anything else life may throw at you.
Single- vs Dual-Wall
Almost always, the chassis of a tube mod will have a single wall—super simple. Just one layer of metal between your hand and your battery cell. There are some mech mods, though, that utilize a double-walled chassis. A classic that comes to mind is any one of the
Hagermann mechs from Purge Mods. These mods use a sleeve-like outer tube that slides over the inner tube while leaving stylish cutouts in the etched design that show the colored wall underneath.
In double-walled mech mods, the venting holes are inherently present, as the inner chassis doesn't raise up high enough to completely close off the battery chamber. In addition, thanks to the space between the outer and inner chassis, heat transfer from the battery cell is greatly reduced, eliminating sweaty mod hands nearly once and for all.
There are a wide number of factors that contribute to the boosted or diminished performance of your mech mod—one of the most important is the state of your threads.
Unfortunately, I don't mean your sense of fashion. I mean, what are your mech mod's threads like? There's two types of threads found in a mech mod: the chassis threads and the 510 threads. The imperfect connection inherent to threading can contribute to unnecessary voltage drop, so it's a good idea to get a mech with only one set of chassis threads, if possible.
Threads are one of the neediest components in your mech mod. Patina and tarnish tends to build up in the fine-toothed threads of your mod, reducing overall conductivty, so you'll need to clean these threads often if you want ideal performance from your device at all times. Similarly, when treating your mech mod with a protective sealant, it's important to avoid getting it on the threading of your mech—this can increase the mech mod's resistance even further, which drastically reduces your mech's potent kick.
Vent holes are a crucial part of a mech mod's chassis—in an emergency situation where your battery is venting, those gases need to be able to escape the device. Otherwise, the gas will continue to build up until the chassis gives way violently and explosively.
Vent holes may be an obvious part of the outer body, or may be integrated into the top cap or firing switch. Some vapers are opposed to having the vent holes facing the vaper during use, though the relevance is up for debate.
Tubes vs Boxes
Tube-shaped mechanical mods and box mech mods behave in very similar ways with only a few differences. For starters, mechanical box mods are likely to accept more than one battery cell wired in series, parallel, or both! Box mechs are also more likely to be "unregulated", which is very similar to a mechanical device, but includes circuit-based safety protections such as MOSFETs and fuses that prevent mishaps like short circuits.
Mechanical vs Unregulated
IMO, mech mods are still entirely mechanical even if they have non-circuit-based protections such as a raised plastic rim around the battery contact for reverse polarity protection, a plastic inner sleeve as a safeguard against wrap shorts, or wires connecting the components together. When things like MOSFETs and fuses—components that cut the circuit when excess power is detected—are added, the mech mod is still unregulated, but no longer fully mechanical.
It's when the power supplied by the battery(s) is purposefully altered each time the circuit is completed by a buck/boost module that the device is no longer unregulated. So even in the case of semi-regulated devices that put out a constant voltage, it's not unregulated unless it's powered by an unaltered
direct voltage from the battery.
But that's just my mere opinion—different vapers have different opinions, so you may find devices being called "mechanical" or "unregulated" when they're only roughly one or the other, but what the device is officially called is entirely up to the manufacturer's discretion.