The "dangers" of silica wicks

[Berylanna]

Since I don't expect to be around in 30 years this is not a big issue for me, but it still bugs me a little. Once I found out that I could rebuild ViVi Nova heads (and lots of other kinds are also rebuildable) with cotton cheesecloth wicks, and that most people review these as tasting better than the original silica wicks, I decided to learn how to do that. Still working on it, I'm getting 50%+ success and even failures can be rebuilt again.

Now I get to hope that Kanthal really is made out of what they say it is and not lead, heavy metals, etc.

(BTW, they DO taste better than the originals, and now I'm also going to try stainless steel...someday)

Please let us know what you find out.

 

[tenshi]

They are without a doubt, amorphous. I'll write more about it later today.

 

[tenshi]

The wicks are not crystalline silica dust. They are definitely amorphous silica. Amorphous silica

Do they break down to crystalline silica dust in our tanks? No, extremely unlikely...

To all those who are worried that the particles they see in their e-juice is crystalline silica dust (e.g. the disappearing wick act)... In order to transform amorphous silica to crystalline silica, it requires hydrothermal conditions 300 to 500 C and incredibly high pressures of 197.38 to 947.69 standard atmosphere pressure (our tanks have 1 atm pressure ).

What are those particles? I don't know but they aren't crystalline silica dust which causes silicosis. Although silica has not been tested in e-cigs specifically, it has been extensively researched. For example, I'm a protein purification scientist and we use silica (specifically gels and column chromatography) in many of our purification techniques (as well as qualitative and quantitative analysis). It's subjected to acids like HCL, Acetic acid, methanol, high heat...etc.

Please remember that many cartomizer/atomizers have silica components and the results of the e-cig studies up to date have proved that e-mist/vaping is safe (no PAH carcinogens nor harmful heavy metals were detected). So, if you don't want to get silicosis, then take precautions if you work around sand, rocks, minerals or in brick plants where you are more likely to come in contact with crystalline silica dust.

 

[rebar]

Good to know thanks tenshi. So the wicks manufacturers use is Amorphous silica which "dissolves in the lungs" according to NAIMA? To bad the International Agency for Research on Cancer doesnt fell the same way..

Glass fiber - Wikipedia, the free encyclopedia


The North American Insulation Manufacturers Association (NAIMA) claims that glass fiber is fundamentally different from asbestos, since it is man-made instead of naturally-occurring.[15] They claim that glass fiber "dissolves in the lungs", while asbestos remains in the body for life. Although both glass fiber and asbestos are made from silica filaments, NAIMA claims that asbestos is more dangerous because of its crystalline structure, which causes it to cleave into smaller, more dangerous pieces, citing the U.S. Department of Health and Human Services:

 

[wootze]

The wicks are not crystalline silica dust. They are definitely amorphous silica. Amorphous silica

Do they break down to crystalline silica dust in our tanks? No, extremely unlikely...

To all those who are worried that the particles they see in their e-juice is crystalline silica dust (e.g. the disappearing wick act)... In order to transform amorphous silica to crystalline silica, it requires hydrothermal conditions 300 to 500 C and incredibly high pressures of 197.38 to 947.69 standard atmosphere pressure (our tanks have 1 atm pressure ).

What are those particles? I don't know but they aren't crystalline silica dust which causes silicosis. Although silica has not been tested in e-cigs specifically, it has been extensively researched. For example, I'm a protein purification scientist and we use silica (specifically gels and column chromatography) in many of our purification techniques (as well as qualitative and quantitative analysis). It's subjected to acids like HCL, Acetic acid, methanol, high heat...etc.

Please remember that many cartomizer/atomizers have silica components and the results of the e-cig studies up to date have proved that e-mist/vaping is safe (no PAH carcinogens nor harmful heavy metals were detected). So, if you don't want to get silicosis, then take precautions if you work around sand, rocks, minerals or in brick plants where you are more likely to come in contact with crystalline silica dust.

Well. That settles that.

This is one of the best posts I've read on ECF.

 

[Berylanna]

Well. That settles that.

This is one of the best posts I've read on ECF.

Yes and no. The idea that glass fibre dissolves in the lungs is ludicrous to anybody that has taken high school chemistry.

And having not found carcinogenic chemicals in vapor is totally different than not finding something that causes cancer by physical means (asbestos apparently causes cancer by irritating, not by chemical action. Like sunlight, not like dioxin.)

According to that Wikipedia article, the jury is still out on what-size a piece of fibrous silica need to be to cause harm.

I take this to mean that going forward, we should still be looking to improve wick materials, and to look at whether or not pieces that break off our wicks during 'disappearing wick syndrome', which I've seen, can fall into the less than 3 micrometers in diameter and greater than 20 micrometers in length" size range.

I also think that vapers are probably pretty safe but not so sure about factory workers in wick factories.

 

[tenshi]

Don't believe everything in wiki. Everyone knows how wiki information is gathered. As a scientist, if I quoted wiki in one of my control test procedures or method development, I'd be fired hehe. They do know what causes silicosis (the topic of this thread), and it is crystalline silica dust which our ejuice before, during and after vaping does not contain.

There is such a thing as particle pollution. No matter what the size, particles can be harmful to your health. Who are the main people at risk? The ones that live where particle pollution levels are high (can look at levels in your state).

So some of these at home studies I've seen here and there in the threads (e.g. the disappearing wick) does not prove that e-cig vapor may cause silicosis. For the sake of argument, lets say they do see 'silica' fragments, they would still have to prove they are crystalline silica dust in order to cause silicosis. There are mainly 3 methods used to determine the difference between crystalline silica dust and amorphous silica since they both are SiO2, and they can not be done at home but in a well equipped lab. Specifically by X-ray defraction or Infra-red spectroscopy only (and advanced chemical bonding methods)... So looking at particles through a microscope tells us nothing.

While it's true that there maybe some possible dangers in vaping, and further studies are in definite need.... If one is so worried about it, then don't vape until valid scientific reports are released. If you feel based on the scientific evidence so far that vaping is safer than analogs as I do, then vape... But assuming something is unhealthy without the scientific proof can deter some people who seriously need to quit smoking analogs and cause them to have unreasonable apprehension to try e-cigs. Up to date, there is absolutely, without a doubt scientific proof that smoking analogs are dangerous to ones health with over 4K chemicals.

 

[Jimi D.]

Thanks tenshi ! I've never doubted silica wicks. I usually don't believe 90% of the stuff on those scare threads anyway.LOL

 

[Berylanna]

While it's true that there maybe some possible dangers in vaping, and further studies are in definite need.... If one is so worried about it, then don't vape until valid scientific reports are released. If you feel based on the scientific evidence so far that vaping is safer than analogs as I do, then vape... But assuming something is unhealthy without the scientific proof can deter some people who seriously need to quit smoking analogs and cause them to have unreasonable apprehension to try e-cigs. Up to date, there is absolutely, without a doubt scientific proof that smoking analogs are dangerous to ones health with over 4K chemicals.

I was objecting to the "we're done" comment. A totally agree with you about combustibles being drastically more dangerous, and I use silica wicks when I don't have time to make cotton ones (which I prefer mostly for taste reasons) but relying on someone saying that some silica just "dissolves in your lungs" makes no sense to me.

If "silicosis" is a name restricted to the effects of crystalline silica dust then by definition amorphous silica cannot cause it. Even if it could cause "something" it would obviously have a different name. And I agree that I have never heard of evidence that silica wicks cause problems. But I'd like to know more about where those missing pieces went. (Probably down the drain when we wash the wicks between refills, but I'd like to KNOW.)

Vaping is safer than smoking, hands down. And in the future vaping may be even safer than it is now.

 

[Boden]

Hey everyone I was just informed about this thread. I have done some reserch on this topic several months ago.

this is a copy paste of things I found.

--------------------

technical: Micron = µ = Micrometer = µm (different sources use these interchangeably)

To clarify

1. It is amorphous not cristalline.
2. The fibers we use are too large to inhale past the throat.
3. If you got some in your mouth you would just spit it out or swallow it.
4. Silica fiber undergo dissolution and transverse breakage due to amorphous structure.

Source: http://www.atsdr.cdc.gov/toxprofiles/tp161-c2.pdf
Different studies have used different rules for counting fibers in air samples, but in general, a fiber is a particle that has a length ≥5 µm and a length:diameter ratio (aspect ratio) of ≥3:1 or ≥5:1. The WHO counts fibers as particles with lengths >5 µm, widths <3 µm, and aspect ratios ≥3:1. The National Institute for Occupational Safety and Health (NIOSH) counts fibers as particles with lengths >5 µm and aspect ratios ≥3:1. The levels of synthetic vitreous fibers in air are measured by phase contrast microscopy (PCM), transmission electron microscopy (TEM), or scanning electron microscopy (SEM) (see Chapter 7 for more details). A human respirable fiber (a fiber that can be inhaled and reach the lower air-exchange portion of the respiratory tract) is usually defined as a fiber having a diameter <3 µm.

...key determinants of toxicity including:
• The amount of material deposited in the alveolar region of the lung (fibers with diameters >3 µm do not reach this region; they are deposited in the upper respiratory tract and lung conductive airways, cleared by mucociliary action to the pharynx, swallowed, and eliminated via the feces);
• The rate at which macrophages engulf and clear fibers deposited in the lower lung (human
macrophages cannot fully engulf fibers with lengths longer than about 15–20 µm); and
• The extent of movement of deposited fibers from the alveoli to the lung interstitium and the
pleural cavity (fibers with diameters >0.3–0.4 µm may move less freely into the interstitium and
pleural cavity).

Fibers that can dissolve in physiologic fluids (i.e., that are less durable) develop weak points that can facilitate (1) transverse breakage by physical forces into shorter fibers and (2) faster clearance by macrophages, compared with fibers that do not dissolve, like amphibole asbestos fibers.

Synthetic vitreous fibers differ from asbestos in two ways that may provide at least partial explanations for their lower toxicity. Because most synthetic vitreous fibers are not crystalline like asbestos, they do not split longitudinally to form thinner fibers. They also generally have markedly less biopersistence in biological tissues than asbestos fibers because they can undergo dissolution and transverse breakage

Note: I underlined the above.

I have never measured a silica fiber used in any ecig product that was smaller diameter than 8 µm, most were between 20 and 35 µm.

-------------------
From: 02-23-2013
There are two types of silica, amorphous and crystalline. The silica fiber used in ecig wicks and electrical sleeving are amorphous, this form does not break down into the very small bits that cause silicosis. Even if they were deeply respirable, the amount (volume) of these fibers needed to cause enough mechanical damage to the lungs to be noticeable is basically impossible in ecig use. The natural airway defenses to particles larger than (aerodynamic diameter)(F*ds) ~4μm is very good and you would just cough it up or digest it.

In the first test I did the average diameter of a ecig wick fiber was ~8μm with a aerodynamic diameter of 16μm under fast inhalation velocity ~5m/sec. edit: I miscalculated the aerodynamic diameter of the wet 8µm wick. The correct number is 24µm not 16µm.


Document Display | NSCEP | US EPA
Pathophysiology Treatment of Inhalation Injuries - Jacob Loke - Google Books
http://www.industrialventilation.ne...Impactor Data Reduction/Impactor_Park (1).pdf
What are the Effects of Dust on the Lungs? : OSH Answers
How Do Particulates Enter the Respiratory System? : OSH Answers
http://www.aeronautics.nasa.gov/pdf...ective_tile_care_and_handling_precautions.pdf
http://www.specialtygaskets.com/files/silicacloth-12.pdf
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1567293/pdf/envhper00401-0085.pdf


Next day edit: 02-24-2013
I just spent the afternoon looking at some samples of silica wicks donated from friends and vivi novas and a few venders. All were in the 20-32μm diameter range. Seems like the really small ones (~8μm) have gone out of fashion. I'll post some pics in a bit. (see pics in next post)

 

[Boden]

This is from: 11-24-2012 When I did some collection tests forcing wicks to shed.
Somewhat outdated as of 3/3/13 (I've learned a lot more about this topic since I wrote this)

I've come to my conclusion. The answer is... It depends. There are so many variables a conclusive answer is impossible. There are some guide-lines that I have found. Before I describe the commons there are some basics people should know. Synthetic Silica Fiber is not the same as Silica, it is heat treated and drawn. This changes the physical properties of the material. In it's crystalline state silica fractures into very small bits that can be easily inhaled. The accumulation of this dust is what causes Silicosis. Silicosis is not a cancerous or mutagenic effect but more like scaring. It is an accumulation over a long time of dust that clogs and damages the lungs.

Synthetic Silica Fiber does not become a powder that would be easily inhaled into the lungs. The fiber segments that were recovered from airborne accumulation were too large to make it past the pre lung filtration (Cilia). Meaning they will irritate the throat and be coughed or flushed out. This is good, if you have a fiber wick that is shedding you will know it rather quickly. I recommend tossing it out if this happens.

The test I devised was rather simple I used a compressor at 2, 3, and 5 psi to force air into a rebuildable Atty through the air-hole and collected the vapor in a balloon. After each sample was taken the balloon was clamped off to allow settling. After an hour the balloon was slowly deflated and then I took 10mL of denatured alcohol and flushed out the balloon (I washed the balloons out before starting) the alcohol was then evaporated off in a glass dish leaving a sample.

Today edit: Understand that I was forcing the wick to shed using high airflow rates that no person would likely produce. Even with this forced shedding, the amount of shed fibers was very very low.

The testing I did was interesting and a bit irritating, literally. I found that if you abuse a wick by using high temperatures (+5v at 2.7Ohms or 9.26W) the breakage was more pronounced. This is clearly because of the more energetic expansion of the liquid into vapor. More particles were ejected into the airstream the higher the voltage became. I freely admit these results are limited to the silica fiber wicks I purchased but the concept should remain constant within minor variations. The airflow pressure was not as much a factor as I thought other than the obvious more is more.

I leave it to you to decide what is right for you. Personally I've re-wicked all my stuff with cotton. Not for safety reasons but I like the sensation it provides and the cost (7$ in organic unbleached yarn = wicks until the end of time)

---------------------------
From: 02-24-2013
I got bored today and mesured the diameter of some silica wicks I gathered.

They were all between 20 and 32 micron, too large to inhale deeply.

These pics are the small versions. I scanned the fibers at 6400 PPI ie 1 pixel = 3.96875 micron. If you zoom in to pixel depth you can calculate the diameter by counting the pixels. The larger files are here: http://s963.beta.photobucket.com/user/revboden/library/silica fiber


Edit: Gahhh!!! I can't get photobucket to stop resizing the images. The originals are about 4 times the size photobucket shows [/QUOTE]

--------------------

To put it simply the aerodynamic diameter of a the (wet or dry) silica fiber we use is too large to reach deep enough into the lungs to do damage. If It does get into the upper airways it will be broken into smaller bits by the movement of the cilia and ejected from the body through the digestive tract.

To help you visualize the size difference between the largest size that is respirable and the size of the fibers we use:

 

[Litcube]

Yup. My OH&S colleagues agree, these things are very unlikely a hazard. I halted the consultation with the hygienist.

 

[DC2]

So dry burning my 510 atomizers might increase my risk then.
If so, perhaps I'll just start throwing them away instead of cleaning them.

On the other hand, if I'm dry burning and then rinsing them out before use...
Maybe there isn't any added risk factor.

Hmmmmmmmm...

 

[Boden]

So dry burning my 510 atomizers might increase my risk then.
If so, perhaps I'll just start throwing them away instead of cleaning them.

On the other hand, if I'm dry burning and then rinsing them out before use...
Maybe there isn't any added risk factor.

Hmmmmmmmm...

No, Dry burning the wicks will not increase risk. Silica fiber has a very very high resistance to thermal shock.

 

[DC2]

No, Dry burning the wicks will not increase risk. Silica fiber has a very very high resistance to thermal shock.

What about this though?

I found that if you abuse a wick by using high temperatures (+5v at 2.7Ohms or 9.26W) the breakage was more pronounced. This is clearly because of the more energetic expansion of the liquid into vapor. More particles were ejected into the airstream the higher the voltage became.

 

[Boden]

What about this though?

"The testing I did was interesting and a bit irritating, literally. I found that if you abuse a wick by using high temperatures (+5v at 2.7Ohms or 9.26W) the breakage was more pronounced. This is clearly because of the more energetic expansion of the liquid into vapor. More particles were ejected into the airstream the higher the voltage became."

That was with saturated wicks in a very fast airstream. Dry wicks experience no thermal expansion or thermal shock at the temperatures you can create with a coil.

Aerodynamic Diameter is somewhat confusing. Think of the aerodynamics of particle flight this way. Even if some of the wick sheds, the bits of wick are too large to turn the corner at the back of your mouth. They stick to the back of your throat, and then you swallow them.

This has been very extensively reserched for about 50 years. None of the studies show a increased health risk for factory workers who work in production of this type of fiber. (except for the hamster test, which was discredited because the method of implantation caused the damage they calmed was caused by the particles.)


If you really want to understand this topic read this: http://www.atsdr.cdc.gov/toxprofiles/tp161-c2.pdf It is about dry particles of all types, focus on the silica fiber which will break down via transverse breakage.

 

[jeffsm3]

Very well written boden!

Aerodynamic Diameter is somewhat confusing. Think of the aerodynamics of particle flight this way. Even if some of the wick sheds, the bits of wick are too large to turn the corner at the back of your mouth. They stick to the back of your throat, and then you swallow them.

When you said this you are referring to inertial impaction. The larger the mass the harder it is to follow the respiratory tracts airways, along with the force of inhalation making these larger particles impact the oropharynx and lyrangopharanx. Mucosa from goblet cells and cilia project the particles that have made it further down and bring them back up by way of coughing or natural cilia movement, where it is swallowed. You also have a ridiculously crazy cough receptor right on top of your carina ( the point where your left and right bronchi take off in there own direction) when larger particles hit this receptor it will make a dead guy cough.

Anyway, another good post boden really nice to see the work you've put in to all this.

 

[pkj]

Thank you, Boden. Appreciate all the work you've put in this project and sharing your findings. Like you, I use cotton because it is what gives me the best results.

Thank you again.
Paula

 

[USDMS13]

Very informative thread! Read from beginning to end! Thanks to everyone for the information and to Litcube for raising awareness on the issue of silica wicks

 

[Plumes.91]

i came to the health forum today because I have been seriously struggling.
I've been struggling with slight nausea, severe fatigue, and chest discomfort.
I didn't know what was causing all of this and I especially wanted to know what the nausea and fatigue was from.
I was getting so sick and tired of this that every day was turning into an experiment.
Was it the nicotine? Was it the PG? Was it the VG? I was going crazy.
I tried lowering my nicotine, no relief. Increasing my dosage, no relief.
I have been through many bottles of juice, different flavors, different pg/vg ratios.
All gave me the same problems. I was starting to really get concerned.
Today is the 1st day I have not used silica for wicking. Today is the 1st day I have NONE of these symptoms.
I have strictly used stainless steel mesh today and I have not felt the foggy head, fatigue, lung pain.
I had a tiny bit of nausea with my 1st vape this morning but it went away quickly.

I'm going to continue using mesh & only mesh and see if symptoms come back.
I just don't know why silica would be the culprit after reading through this thread.