I'd also mention that Dr. F was basing his study on power while Mike is using temperature, a much more reliable indicator.
Ah I see, I wondered how to compare results, but mikes last graph is per puff too.Thermal degradation.
But please note that even Mike's highest values per puff at 500°F are lower than those observed by Dr. Farsalinos, and Dr. F. considered those values to be "minimal".
How are the results in comparision to Dr Farsalinos study, in which they found that only in "dry puff conditions" there were worrysome amounts of formaldehyde etc.
E‐cigarettes generate high levels of aldehydes only in ‘dry puff’ conditions
"Minimal amounts of aldehydes per 10 puffs were found at all power levels with A1 (up to 11.3 µg for formaldehyde, 4.5 µg for acetaldehyde and 1.0 µg for acrolein) and at 6.5 W and 7.5 W with A2 (up to 3.7 µg for formaldehyde, 0.8 µg for acetaldehyde and 1.3 µg for acrolein). The levels were increased by 30 to 250 times in dry puff conditions (up to 344.6 µg for formaldehyde, 206.3 µg for acetaldehyde and 210.4 µg for acrolein, P < 0.001), while acetone was detected only in dry puff conditions (up to 22.5 µg)."
Here you and the study state that emission even increase when under "wet" conditions, do you have an explanation for the differences?
Every single test was with a fully saturated wick, there no "dry hits" involved in my study.Here you and the study state that emission even increase when under "wet" conditions, do you have an explanation for the differences?
Hmmmm, dont remember, depends on what weekend it was.
Standard deviation is an statistical indication of how repeatable a set of tests are. If the SD is large it means your testing wasnt very good. The pic shows the SD for this dataset, and it didnt indicate a large deviation, indicating the tests were within a decent tolerance of each other, ie not a technique problem.
Most scientifically "published" data will show SD for all of their testing, it is a confidence indicator.
In layman's term, it an indicator of the quality of the series of testing performed under identical variables. Low SD is good, high SD is sloppy.
@Katya and @Katdarling :
Maybe you two should just stop fighting it and get into vaping with TC?
Although some gear doesn’t go that well with TC (e.g. Kayfun 4), the transition is otherwise really not that bad. I have no doubt that you both have the skills to handle it.
[Psst: TC builds in my Ego One tanks work fine.]
How much formaldehyde you choose to allow yourself to be exposed to is a personal decision.I thought F´s study is not really about watts but about emissions when a human detects a dry hit compared to those when the testsubject thinks its still ok.
Bottom line of Fs study is like "as long it doesnt taste burned, its ok"
Though that doesnt really matter as Rossum mentioned that Fs values under non dry hit conditions are like your max values.
"Minimal amounts of aldehydes per 10 puffs were found at all power levels with A1 (up to 11.3 µg for formaldehyde"
So like 1 µg per puff, which you found with 100% VG at about 490°F, right?
So, even if you found those emissions, I wonder -is it something people should worry about at all?
As in everything is toxic, it really depends on the dose.
I tried TC, used it for a month or two (found out that the best temperatures for me are at below 400F). Returned back to power mode. I feel myself reasonably safe, because I can run my builds at 25W and higher, but actually I vape only at 10-12W, so my temperatures are much lower than that of dry burn effect (500F, according to Mike).
Important thing from Mike's research:
We cannot anymore advice novices with VW setups "to go up until you feel bad taste and then go back a click or two". It will put them in a temperature range of elevated formaldehyde.
Corrected. Dry hit was replaced with "bad taste"I never said 500F was a "dry" burn, true dry hits are much hotter. My wick was not at all dry at 505F.
Just dont want to confuse a "burnt flavor" with a dry hit, two very different things. A dry hit tastes like the Devils .... and will burn your throat and lungs.
A dry hit is when the wick is not saturated enough and the temps will skyrocket well above 500f.
Yes, I have been contemplating that all day. VG acted as expected, but the 50/50 mixture did not.I recall a hundred or two pages ago that the relative boiling points of PG, VG and water were thought of as reasonable predictors of when thermal degradation may occur. The 50/50 results show a different result. Interesting!
And actually, it wasnt be thought of as an indicator of thermal degradation at all, except to get under 410 at the coil based on Wang. It was proposed that you could use BP to reduce the temp required to get a satisfying vape. It was about lowering your power/temp.I recall a hundred or two pages ago that the relative boiling points of PG, VG and water were thought of as reasonable predictors of when thermal degradation may occur. The 50/50 results show a different result. Interesting!
Its not the sensor, I just repeated three reading of pure VG, 470, 480, and 490, and all three were in the exact same range as originally recorded. So the sensor is fine.Yes, I have been contemplating that all day. VG acted as expected, but the 50/50 mixture did not.
My next step is to measure some 100% PG juice, to see if I see any clues there. Not gonna happen today though.
One thing I have been contemplating is that the 200+ tests I have done may be leaving a film on the sensor, it certainly left a film on the outside of the probe and inside of the chamber. I took it apart but did not detect anything, however there is a porous membrane on the sensor. I am afraid to apply any sort of alcohol or cleaner to it for fear of ruining it. The sensor is made by DART. I am going to contact them, although I expect to get blown off as not using the meter in a manner for which it was designed.
https://dart-sensors.com/wp/wp-content/uploads/2014/10/HCHOSensorDatasheet.pdf
Dart Sensors Ltd – Product categories – Formaldehyde Sensors
View attachment 695055
Kat, from all the reading I've done, and I'm not a researcher or physicist by any stretch, Ni, Ti and SS only emit things we might not want to inhale at temperatures in the range of 800F and higher. Since vaping at those temperatures wouldn't taste very good, or be vapeable at all, I stopped worrying about it.
I have a feeling the next generation of TC won't have the restrictions of wire types and will, probably, use a different method, thermistor, to determine temperature but that will require a completely different connector to replace the 510 we all know and "love".
Incidentally, kanthal contains iron, chromium and aluminum and relies on a layer of aluminum oxide, on its surface, to remain stable
On another note, a B flat, I just saw another "exploding e-cig" report on the early morning news here, Philly ABC station. The user says he only had it for a week, had not modified it, and it blew up in his face when he took a puff. He looked kind of "gamey" in the video and says he's done with e-cigs. No other details, as usual, so in my mind the jury is still out, but the narrative is being well supported by stuff like this.
I was surprised by the 50/50 curve as it didnt correlate as close as the VG curves did to Wangs study. I expected it to be lower than 100% VG, but this is what the data showed, and I did 5 samples at each temp and the SD was pretty good across the board.
And I daresay, will CONTINUE to do so......We've been improvising from day one.