broken.english
Jedi Master
Content
May 20, 2016 - TDP2
Vegetable glycerin(vg) vs propylene glycol(pg)
Experiments
- Experiments 1 and 2 - Testing the waters
- Experiment 3 - Natural tobacco
Hardware
- Form factor
- Batteries
- Atomizers and coils
May 20, 2016 - TDP2
On May 20, 2016 the latest EU regulation on tobacco products, TPD2, Link http://ec.europa.eu/health/tobacco/products/revision/index_en.htm will come into force. It contains quite a number of restrictions for e-cigarettes and liquids. The most important one seems to be that refillable containers for nicotine liquids may have a max. content of 10 ml and a max. content of nicotine of 20mg/ml. Until now consumers can easily buy nicotine base liquids in liter bottles up to 72 mg/ml nicotine and mix their own DIY liquids as they please. Compared to cigarettes the cost of such liquids is very low. As an example one liter of nicotine base(72 mg/ml) can yield four liters of liquid(18mg/ml) at a price of roughly 100 euros. Depending from consumption this can last for more than 1000 days of vaping. Many vapers just need 2-3ml per day. Some extra cost has to be added for flavours and maintenance but this is not very high. All in all, at current price levels, it is possible to vape for 15 - 20 cents a day.
After May 20 consumers will have to buy commercial products at higher prices, of course, and may not always be happy with their ingredients and taste. In other words, everybody, who is vaguely interested in e-cigarettes should look into this matter now, before the restrictions will come. In some EU countries they are already in place and outside EU similar regulations are being considered here and there.
I have been smoking RYO cigarettes for many years and I still like them. However, with smoking restrictions left and right I gradually became more open to the idea of vaping e-cigarettes. Also I must say that the smell of smoke in my own home bothers me a bit in the winter season. A few weeks ago I met an elderly man, a former smoker, who was so happy with vaping his e-cigarette, that I decided to give it a try and invested 15 euros in my first e-cigarette.
Just to have a start I tried some commercial tobacco liquids. The taste was just so acceptable but nothing that would replace my RYO cigarettes. Not even part time. From that it was clear that I would either give this up soon or find something that would suit my taste. Maybe DIY? This idea led me deep into the DIY sections of various e-cigarette forums. A few hundred posts later I returned with the plan to extract the flavour of natural tobacco and make my own liquid.
First problem: what nicotine base should I choose, vegetable glycerin(vg) or propylene glycol(pg)?
Vegetable glycerin(vg) vs propylene glycol(pg)
- In a recent study in Poland http://ntr.oxfordjournals.org/content/early/2014/05/14/ntr.ntu078.full pure pg and vg did not produce measurable harmful substances in an e-cigarette with the exception of smaller amounts of butanal depending from the voltage of the e-cigarette. As for butanal the values for vg are substantially lower than those of pg. The study also says that in general, the highest levels of carbonyls were observed in vapors generated from PG-based solutions(solutions in this case means commercial e-liquids with added flavours). This finding suggests that PG in ECs is more susceptible to thermal decomposition than VG. VG is clearly the winner of this contest.
One remarkable detail is that liquids with a mix of pg and vg have higher values of formaldehyde and acetone compared to pg-only or vg-only liquids.(s. Figure 1) http://ntr.oxfordjournals.org/content/early/2014/05/14/ntr.ntu078/F1.expansion.html
- From another study, Toxicological evaluation of glycerin as a cigarette ingredient http://www.ncbi.nlm.nih.gov/pubmed/15967561, I learned that "glycerin is applied to cigarette tobacco at levels in the range of about 1-5% to improve moisture holding characteristics of tobacco". Also natural tobacco leaves contain a certain amount of glycerin depending from plant. The levels are from 0,07 to 0,48%. That means the tobacco I have been smoking contains 1,07 to 5,48% glycerin. If I would smoke 20 grs of tobacco per day, which I do, I would inhale from 0,214 to 1,096 gr of glycerin even without e-cigarettes involved. I will come back to this later.
- Both pg and vg are alcohols and can irritate skin and respiratory pathways. There can be intolerances and allergies too. Allergologists seem to be a bit reluctant, when it comes to the allergological potential of pg as it is widely used in cosmetics, medications a.s.o and considered as useful. However, there are some clinical tests https://www.researchgate.net/profile/Klaus_Andersen2/publication/16114327_Skin_irritation_caused_by_propylene_glycols/links/09e415024c30190bdd000000.pdf
showing allergic reactions to pg for at least 1% of tested persons. On vg the German cancer research institute DKFZ speculated it could cause lipoid pneumonia only to find themselves corrected by US researcher Dr. Siegel who soberly stated that vg is an alcohol, not an oil. Link http://tobaccoanalysis.blogspot.de/2013/05/german-cancer-research-center-lies.html
In any case, people with pg or vg allergies will surely have a problem with e-cigarettes, too. For some there can be a practical solution though. I went through a whole lot of post in various e-cigarette forums related to intolerances and allergies. According to these posts the overwhelming majority of intolerance problems is caused by pg and disappeared when the users switched to vg. This will not help people with vg allergy but some others.
Based on the above I could make an easy decision. I will use vg as nicotine base.
Experiments
Experiments 1 and 2 - Testing the waters
In my first two experiments I wanted to find out, how much water I could add to my liquid, as I wanted to take a puristic approach. I found it strange that DIY recipes and related discussions never ever go beyond 10 or maybe 15% of water content. There is a liquid shop in Germany who offer distilled water with added nicotine(18 mg/ml) for DIY mixing purposes. So I took the opportunity and in my first experiment I tried to vape pure water with 18mg/ml nicotine.
Exactly as I had predicted the taste was rather watery and the exhalation cloud almost invisible. The nicotine delivered a mild throat hit similar to a cigarette. However, without any tobacco or other taste this does not really satisfy a smoker's needs. At least not mine. It may help in an emergency though.
In my second experiment I mixed distilled water with vg. Already at 30% vg the mixture produced clouds comparable to the smoke of a cigarette. The taste is still pretty much in neutral territory. This will do for me just fine and will be the basis for my future mixing recipes with tobacco.
The daily amount of vg I would inhale with this mix is relatively low: 2-3 ml x 30% = 0,6 - 0,9 ml. This is rather close to the 0,214 - 1,096 gr of vg that I inhale by smoking.
In other words, it does not matter much whether I smoke or vape as far as vg is concerned.
Experiment 3 - Natural tobacco
Natural tobacco flavour can be extracted from tobacco leaves with DIY or industrial methods. The industrial products are ultra strong concentrated extracts called tobacco absolute. As for now I will not follow this up because they are hard to get, must be diluted and finally need up to six months of aging before they develop a pleasant flavour.
For short term results it is more practical to use one of the DIY methods as per the short guide here. http://www.wikivapia.org/wiki/Naturally_Extracted_Tobacco
Basically the tobacco is soaked in either alcohol, pg or vg for some days and then filtrated. The final product is called NET(naturally extracted tobacco). It is fairly easy but can go wrong. The pros and cons and all slippery details are extensively discussed in the e-cigarette forum. https://www.e-cigarette-forum.com/forum/threads/natural-tobaccos-part-deux.519685/
Last time I looked the thread had 686 pages.
For my own experiment I opted for a 7-day alcohol extract of the tobacco I regularly smoke, which is a Kentucky dark fired halfzware shag. In short: it worked. The extract came out with a nice smell of tobacco, so I made some test mixtures from 10-25% extract, 30% vg and distilled water. Then the vaping test and comparison with my normal cigarettes. The first few draws on my e-cigarette were not very impressing but when the liquid warmed up it developed distinct tobacco flavours, smooth but rich. In one word: delicious.
I have been smoking this tobacco for several years and I always liked it. However, when smoking I was never able to taste all the rich flavours, which are delivered by the extract, even at a small dosage of 10%. This is the real surprise of this test. I feel encouraged to continue my experiments and I am curious to find out how other tobaccos will taste like.
It seems I am not the only one, who is positively surprised about tobacco extracts. Here is a short quote from the e-cigarette forum:
" I cant believe how much flavor there is with N.E.T.'s Compared to actually smoking, Smoking is very harsh but vaping Tobacco is nice and smooth.
Oh Yes!!
Even when I was smoking, the smell of the fresh tobacco was always SO much better than the taste of the ciggy....it's only taken Me 35 years to realise that the taste of tobacco is ruined by setting light to it! "
Now let me get back to the sobering world of science. I wanted to know, how tobacco extracts are faring in comparison with tobacco regarding any potentially harmful substances. Thankfully there is a study http://www.mdpi.com/1660-4601/12/4/3439/htm which covers the subject. They examined TSNAs(tobacco specific nitrosamines)*, nitrates, phenols, formaldehyde and acetaldehyde.
The results are shown on tables 1-3(link not possible). All values are much lower than in tobacco smoke or even below limit of detection:
TSNAs*: in total 218 times lower
Nitrates: 313 times lower
Phenols: 160 times lower
Formaldehyde/acetaldehyde: no significant increase in NET liquids compared to commercial liquids.
All these are very good results for NET liquids. They would be even better, if the following would be considered:
- The study compares 1 gr of tobacco (1 cigarette) with 1 ml liquid. However, 1 ml liquid rather corresponds to about 5 cigarettes.
- Most liquids tested are a mix of pg and vg, which is not ideal concerning formaldehyde and acetone values even though they are low.
* On TSNAs there are very dissenting opinions. The research goes back to Stephen S. Hecht http://www.cancer.gov/research/nci-role/spotlight/merit/hecht who declared them as carcinogens but was later heavily criticized in a review titled An Analysis of the Role of Tobacco-Specific Nitrosamines in the Carcinogenicity of Tobacco Smoke http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2651603/#.
In the review, citing lots of other studies, it says that
- the amounts of TSNAs, namely NNK, injected into rats were so high that they equal 22 to 83 million cigarettes for a 70 kg human.
- nicotine, cotinine and aqueous cigarette tar extract inhibit the mutagenicity of NNK
- that based on the published literature there is no convincing evidence that NNK or TSNA in toto play a significant role in the increased risk of lung cancer associated with cigarette smoking.
So be it.
Hardware
So far my experience is limited but I already learned some things the hard way and would like to make a few proposals.
Form factor
Long e-cigarettes have a nasty tendency to topple over and are not practical to transport. The shorter versions with a diameter of 22 mm and length around 12-13 cm are much more ergonomic to handle. They are available with fixed or exchangeable battery, with or without electronic regulation.
Batteries
Exchangeable lithium ion batteries for 22 mm tubes are available in sizes 18350(18 x 350 mm), 18500 and 18650. Their safety characteristics vary with chemistry. As lithium is highly reactive it is recommendable to choose batteries which contain manganese such as LMnO batteries. This is considered the safest chemistry currently available and it is unlikely that such a battery will burst into flames.
There have been reports about exploding e-cigarettes. According to a FEMA survey https://www.usfa.fema.gov/downloads/pdf/publications/electronic_cigarettes.pdf 25 cases were reported between 2009 and August 2014. In 20 cases or 80% the incident was caused during charging with incompatible battery chargers. In the remaining cases the cause is unclear. It could be short circuits caused by an improper connection between battery and atomizer. This can happen, as another youtuber explains, https://www.youtube.com/watch?v=nJKtJ00jSiQ when the plus pole does not sufficiently protrude from the atomizer and the battery gets in contact with the atomizer body.
Atomizers and coils
There is a rich choice of atomizers made of stainless steel and glass so there is no real need for consumers to heat plastic and inhale the fumes. What I found really nasty though, is the subject of prefabricated heating coil heads. They must be exchanged every week or two, so I purchased a few sets. From these at least 20% did not work at all. The technical term for this is DOA, dead on arrival. A few more just worked for two or three days. Very, very nasty. It is possible to rebuild them, there are tutorials on youtube, but they are fiddly to work on. A more comfortable solution, which I chose, is to buy rebuildable atomizers. They have larger building decks and it is relatively easy to exchange the cotton or wire mesh which transports the liquid. As always, youtube has tutorials on this such as this one. https://www.youtube.com/watch?v=TAGukab4PYA
As for heating wires for the coils my personal choice is stainless steel 316 L. It has molybdenum in it and is the most stable material I could find aside from platinum-iridium wire for users with unlimited budget. What I would avoid at all cost is the increasingly popular nickel wire. A short look into a material safety data sheet http://www.durhamtech.edu/faculty/safety/MSDS%20Files/MSDS%20-%20Chemistry/Nickel.htm
should make this very clear.
