What is the gunk that builds up on wicks?

[Lastlokean]

Many of my friends come to me with their ecig related issues... I'm pretty handy with rebuilding, as I'm an electrical engineer... But lately my whole group of friends has begun to question the 'healthiness' and the 'tar-free' claims...

The particular claim is about what is building up on the wick/coils is clearly resinous / tar like soot. I have always thought it was caramelized sugar / flavoring. One of my friends has been vaping 0 nicotine and 0 flavoring. After about 30 ml of juice through a vivi nova it is quite clear that straight up 50/50 pg/vg builds up something nasty on the wicks.

My current theory is that it is acrolein polymerizing onto the metal. I have this theory because it only seems to happen where the vapor is being made directly? Another one of my friends... A chemical engineer believes that some form of electrolysis reduction is occurring when juice crosses the coils. Allowing some current to pass through the glycerin itself and producing god only knows what.

Are there any studies / analysis / information on the crud that builds up on a wick / wire I can use to put my mind at ease on the subject and refer my fellow vapors to read?

Any information would be greatly appreciated!

 

[Hoosier]

Sure, just read the chemical spec sheets. The spec for VG has a higher quantity of residue left over after being boiled away than PG, but there is residue left behind by both. Then add in that USP requires at least a 99.5% purity which means there is an additional 0.5% of other stuff to be left behind. Even if the entire 0.5% was water, I don't think that is sufficient water to cause polymerization as you're seeing it and since acrolein will polymerize in the presence of oxygen and water at concentrations above 22% into a porous hard compound, and the the gunk on my coils is anything but porous and I also doubt the presence of enough water. (Without water it is suppose to be a clear-to-yellow substance which I've never seen either.)

VG is classified as a carbohydrate. Heat any carbohydrate up and dehydrate it and you will have gunk.

While I am not aware of any studies on crud, I'm unsure why it would be a complicated subject. I evaporate distilled water every day. I use distilled water because it means I have to clean the tank less. Does not mean there is no residue left behind, just less. If residue is an issue with your vaping, use less VG in your flavorless 0nic mixes. It will be kinda' like me with the distilled water, won't eliminate it, but will make it an issue fewer times throughout the year. (Also having only air that does not have any particulates in it going into the atomizer will have to help too as I notice more residue in my water tank when the pollen count is high.)

Also reassure your friends that vaping is not healthy. Just like inhaling anything but pure air is not healthy. There is no healthiness in vaping. Is it safer than smoking, yes, but that does not mean healthy nor safe. Also tar is produced by combustion and a wet coil cannot do that, so keep the coil wet and tar should be well minimized. (Evaporation of the liquid on the coil cools it.)

 

[Kent C]

I use AG - aqueous glycerin from Decadent Vapours (VG + H20 distilled) for my nic base and blend. Vaping just that, with no flavoring, produces no gunk - in fact it tends to clean gunk off coils and wicks. The darker my ejuice from the particulates in the flavoring - the more gunk. I clean with pga 151 proof vodka and that does a good job of cleaning the gunk off the coil and wicking. I don't dry burn... Agree with Hoosier on the fact that "tar" (as defined in cigarette smoking) is produced by tobacco combustion not vaporizing ejuice.

 

[Katya]

The subject of glycerin and acrolein has been discussed many, many times on this forum. You may be interested in doing a forum search--there are some great conversations on the subject, all leading to the same conclusion: a wet atomizer coil is not hot enough to achieve high enough temperatures (280-290 C) required to decompose the VG into acrolein. Our atomizers do not usually reach temperatures above 250 C. I also suspect that we would be able to detect if acrolein was produced--acrolein is a well-known lacrimating agent and would cause massive eye-tearing and runny nose. If you're concerned, use a PG/VG blend, make sure that your atomizer is always well saturated--avoid dry hits--and don't vape at high wattages.

BTW, cigarette smoke most certainly contains acrolein--that has been well documented.

Here's an interesting experiment:

http://www.e-cigarette-forum.com/fo...rolein-vg-simple-test-results.html#post479418

http://www.e-cigarette-forum.com/fo...ing/341778-acrolein-vg-vapor.html#post7506285