One of the biggest choices you have to make when you start rebuilding atomizers is which wicking material to use, and there is a hell of a lot of speculation regarding the potential risks of different materials and the best option in terms of flavor and performance.
Additionally, most wick materials require some form of preparation prior to usage in order to maximize their effectiveness and to remove any potential contaminants. There is no actual research on the potential health effects of vaping with different wicking materials, and although that may worry some, it’s important not to be taken in by blind speculation, and to keep in mind that the alternative is still undoubtedly more of a risk.
If you’re heating anything to the point of glowing or torching your wick, exercise sensible caution around fire!
Boiling (or otherwise cleaning) your wicks is almost always necessary, and although torching and oxidizing accomplish the same tasks, it’s better to do both to prevent any contamination from manufacturing processes.
Cotton should never be dry-burned, and you shouldn’t dry-burn silica for a long time; only briefly to remove residue from manufacturing.
There are many unproven and uncertain concerns regarding wicking material, but little firm evidence on which to base any advice. It may be better to stick to Ekowool silica (or any other that is stated to be almost all amorphous silica) and to oxidize stainless steel wicks without heating to the point of glowing red.
Wick Building Safety
There is little danger when it comes to actually building your wick; the main concern is when it comes to preparation, but thankfully everything is pretty much common sense.
The most risky materials to use when it comes to building are things like stainless steel and some ceramic options which require high temperatures to oxidize or clean, respectively. The lesson here is a simple one life should have taught you a long time ago: be careful around stuff that’s hot. Many vapers torch the hell out of stainless steel wicks, often till glowing red, and this should only be done with a suitable tool to hold it over the flame. Anything thin, metallic and long is suitable; even a stretched out paperclip will do the job if you maintain as much distance as possible from the fire and glowing wick. This – at least in some form – is needed to reduce the chance of shorts, but may come with its own problems, beside the potential burns if you don’t exercise caution around extreme heat.
Cotton may need to be boiled for cleaning (it’s still advised as an extra precaution even if it’s untreated, 100 percent cotton), and you should exercise as much caution with retrieving it from boiling water as you would an egg, or a hunk of biscuit that’s just fallen into a cup of scalding coffee. Also, when testing a coil you should never dry burn cotton: it may lead to an actual fire, so only activate your coil when there’s juice soaked into the wick.
For silica, manufacturing processes can leave behind residue, so a brief torching, dry burning or cleaning in hot water (or a combination of cleaning and torching/burning) is advised to remove any unwanted remnants. Generally, you shouldn’t dry burn silica for very long, so add a little juice if you’re testing a coil at length.
It’s also worth cleaning stainless steel mesh before oxidizing, by boiling for five minutes, changing the water, then boiling for another five minutes. This is due to some oily residue which may exist from the manufacturing process, but a heavy torching could also rectify this issue.
Ceramic wicks require a similar but slightly more laborious cleaning (heat-cleaning if you’re using braided ceramic like Nextel XC), which is detailed on the Reddit RBA Wiki. The braided ceramic may also fray when cut, so it’s best to do so with something pretty sharp. The porous solid options are easy to break, so you should avoid knocking to the side it when it’s standing up in your wick-hole. In either case, be wary of any sharpened edges and shards, protecting your hands when picking any pieces up if necessary.
Stainless steel is a metallic alloy known to contain at least 11% of chromium; chromium in solid stainless steel should not be regarded as a health hazard. Hexavalent chromium can be formed when performing “hot work” such as welding on stainless steel. In these situations, high temperatures involved in the process result in oxidation that converts the chromium to a hexavalent state. Hexavalent chromium is very toxic, is found in tobacco smoke, and is known to cause lung cancer. Hexavalent chromium formation during vaping has not been investigated, but it can be generated before use, when people oxidise the stainless steel wick/mesh by torching it until it glows red-hot. The real problem is that we do not know if this previous oxidizing process results in an instability of the chromium-ion bonds with subsequent release of toxic chromium even at normal operating temperatures. In absence of clear demonstration of hexavalent chromium in the aerosol of e-cigarettes, my personal advice is to use organic unprocessed wicks (e.g. cotton). – Professor Riccardo Polosa
Wicking Materials Safety Concerns
There is a lot of general concern about the risks with regards to different wicking materials, but little actual evidence of the quantities of potentially harmful components vapers would be exposed to or the risk it would carry.
This presents a problem for safety-conscious vapers, who may be worried about things like silicosis or hexavalent chromium exposure following the torching of a stainless steel wick, but have little information to allay their fears. Professor Igor Burstyn from the Drexel University School of Public Health pointed out by email that, “My review of literature did not indicate concern with silica and chromium. I am not aware of any research focused on wicks and am aware of no evidence supporting emission of particles from e-cigs.” This illustrates the core issue for vapers; there is no evidence of risk (so no need to be too concerned) but the available data is still very limited on this issue.
Silicosis is a serious condition resulting from regular, long-term inhalation of particles of crystalline silica, and many are concerned that silica wicks may lead to this too. It’s worth noting that the primary risk groups for silicosis are construction workers, quarry workers, and those working other jobs involving silica-heavy stones like concrete, sandstone, granite and slate. Slicing through a rocky deposit of crystalline silica understandably releases a lot of it, so it’s reassuring to learn that out of all of those workers in the US, in 2002, only 148 died as a result of silicosis. Even if it was crystalline silica used in wicks, silicosis is a rare condition even with so many at-risk workers. Ekowool is 98 percent amorphous silica, but there is no evidence of the crystalline form of silica in any of the research on the components of vapor. With all things considered, silicosis is unlikely to be a concern to vapers, and even if it was, it would likely take decades to develop.
Hexavalent chromium is a carcinogen, and may be produced from the high temperatures involved when oxidizing a steel wick with fire. The concern regarding this is that it will find its way into your juice and over time could increase vapers’ risk of cancer. There is an occupational exposure limit set at five micrograms (millionths of a gram) per cubic meter of air as an eight hour average, but the level of exposure from vaping from a SS wick is uncertain. It’s argued that oxidizing by coating the wick in e-liquid and then burning it off (numerous times) would reduce the overall temperature involved (since it ordinarily glows red during torching) and reduce exposure, but this is again uncertain.
A result for the presence of silica particles is meaningless for health assessment unless the crystalline form of SiO2 is known to be present and currently there is no evidence of this in the aerosol of e-cigarettes. Silicosis is a form of occupational lung disease characterized by inflammation and scarring of the pulmonary tissue. It results from long term exposure to crystalline silica dust (NOT silica particles), usually appearing some 10-30 yrs after first exposure. Even in the event that current silica wicks would be found generating significant levels of SiO2, e-cig technology is known to innovate at such a fast pace that in a few years this hypothetical risk will be minimized as well. For these reasons, any concern with regards to the potential for silicosis in regular vapers is purely theoretical. – Professor Riccardo Polosa
Silicosis seems extremely unlikely to be a risk — there is not going to be much (or any) crystalline silica in the wicks. It would be fairly cheap and easy to test to confirm this. Chromium was not found at levels that pose any concern in the Burstyn review. However, the overheating that is associated with that concern does pose at least one known nontrivial problem: it generates a large amount of acrolein. It is reasonable to guess that very high temperatures will product other unwanted pyrolisis products and outgas some of the material from the hardware, so it is just best to avoid overheating.
Despite being able to conclude there are no apparent substantial risks, and to specifically rule out small exposures one at a time and for each particular device and usage pattern, it will be a long time before we can assess every small potential risk. As large manufacturers develop highly-controlled products, they will perform extensive tests on them and be able to rule out a lot of the small speculative risks for each unit of those standardized devices. But this cannot be done for the countless variations of mods, and so we are limited to the information that generalizes (like the problem of overheating). This is why I point out that we should not assume that e-cigarettes — in their present form — are quite as low risk as smokeless tobacco. – Carl V Phillips (Scientific Director for CASAA), in consultation with Igor Burstyn, Anti-THR Lies
Wicking materials are likely to be safe – especially compared to a cigarette – but there are some unaddressed concerns that may make vapers decide to exercise caution. If you’re concerned, a cotton wick may be the safest option (although there are similar worries from some regarding “cotton lung”), but until there is firmer evidence either way (based on actual exposure levels for vapers), taking simple precautions is a more reasonable course of action than changing your vaping habits altogether.