New studies find carcinogens in vg and pg at high temps, even in tootle puffers

[Alien Traveler]

Same thing happens with my cooking oil
So we get at least some of our vapor well below the boiling point. No surprise, but interesting.

alien Traveler" data-source="post: 19527689" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch">

Not a vapor. Smoking means decomposition, almost certainly producing carcinogenic compounds... It's a bit of VG chemistry I do not really understand. A bit I am a bit afraid of.

Nah, its vapor. boil water, the water vapor starts before it boils. Quite different than burning

Oil smoke is not a vapor, it is a smoke.
Smoke point - Wikipedia

 

[David Wolf]

alien Traveler" data-source="post: 19529215" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch">

Oil smoke is not a vapor, it is a smoke.
Smoke point - Wikipedia

Ok, I'll go with that. The "smoke point" of palm oil is 455 F. VG is made from palm oil typically, and Mike had "smoke" which was likely vapor above 300F. So there's that.
Update:
I accept your fact that "smoke" is smoke, and I misused the term, but put forth that vapor is not smoke until its overheated, and that what Mike saw at a lower temperature of 300F and up to the smoke point was vapor, not smoke, based on this:
Heating glycerin or propylen glycol?
Which really gets to the point that PG and VG can produce vapor well before the boiling point (or the smoke point, and I don't know if that's the same as the smoke point for say pure VG) and Mike proved that with his tests.
This chemistry site provides the best description I have seen regarding vaporizing PG/VG vs. higher temperatures (combined with oxygen) that produce aldehydes;
How does propylene glycol/glycerin form formaldehyde/acetaldehyde when vaporized with a vaporizer?
"In a vaporizer, the idea is to get the propylene glycol, glycerine, and and "flavor" molecules into the vapor phase (or into aerosol droplets) without chemically degrading them.

However, the way this is accomplished is with very high-temperature resistor coils - the idea is that if you have a small amount of heat in a confined space, and the liquid is distributed throughout an absorbent (like cotton, for example), then the heat transfer will happen very quickly and a large amount of liquid will be vaporized.

The problem is that when you have a very high temperature heat source, and there is lots of oxygen in comparison to the liquid, there is a good chance that at least some of the liquid will reach the combustion temperature instead of just vaporizing.

What happens is that the hydrocarbons in the propylene glycol and glycerin molecules are partially oxidized - oxygen reacts with them to "steal" electrons. If the combustion was complete, you would wind up with just carbon dioxide and water. When combustion is incomplete, you can get any number of compounds, two of which happen to be formaldehyde and acetaldehyde. Carbon monoxide is another one I would be concerned about."

 

[mikepetro]

Samples are all made, need to grab some lunch then it will be time to start boiling and vaping......

 

[mikepetro]

......Mike had "smoke" which was likely vapor above 300F.

Just for clarification, I kept using the word "foggy" because I have no clue whether it was smoke or vapor. And I didnt stick my nose in the stream to find out, was kind of keeping my distance from the pot, didnt want to bump it or whatever.

Both the PG and VG started giving off smoke/vapor/fog well below their boiling points though.

 

[awsum140]

Hey Mike, maybe alert the local fire department, just in case, due to all the "smoke"

 

[David Wolf]

Just for clarification, I kept using the word "foggy" because I have no clue whether it was smoke or vapor. And I didnt stick my nose in the stream to find out, was kind of keeping my distance from the pot, didnt want to bump it or whatever.

Both the PG and VG started giving off smoke/vapor/fog well below their boiling points though.

Yeah I wasn't sure what to call it either as you can see, lol. In any case your experiments are awesome man!

 

[corn flakes]

Samples are all made, need to grab some lunch then it will be time to start boiling and vaping......

View attachment 654741

Be careful with the nic. If different liquids start boiling at different temps you could get a lot of nic in a short time.

 

[mikepetro]

Be careful with the nic. If different liquids start boiling at different temps you could get a lot of nic in a short time.

You are dead on the money!

 

[awsum140]

Hope you've got lots of fans going, Mike, both intake and exhaust.

 

[mikepetro]

Nic buzz city, even with exhaust fans and open windows.

I am not doing this for the rest of the samples, going to use "Theoretical Boiling Point" for the vape temp tests as the nic (and I use higher mg than most) didnt change the BP much, lowered it 3 degrees is all.

ETA: dropped volume measurements, something was wrong.

 

[mikepetro]

One thing for sure, I dont think there is much danger of folks going much over 500F with a 50/50 blend. The smell I got today at 500+ was the same as what I tasted in wattage mode when the thermocouple went over 500. Not a "dry hit" but a burnt hit. And smelling this, it is the same, it is burnt juice, not wick or whatever.


ETA: What I was probably tasting and smelling was higher levels of acrolein.
"Glycerol decomposes into acrolein at ~535 F (~280 C)."

 

[Alien Traveler]

Nic buzz city, even with exhaust fans and open windows.

I am not doing this for the rest of the samples, going to use "Theoretical Boiling Point" for the vape temp tests as the nic (and I use higher mg than most) didnt change the BP much, lowered it 3 degrees is all.

One thing that strikes me as odd is the low specific gravity of the end result.

View attachment 654773

View attachment 654763

View attachment 654765

ETA: CORRECTION, typo, was supposed to say "Lots of smoke at 350"

Very interesting. And as expected it became lighter after boiling (specific gravity decreases). But something wrong with your volume/weight measurements.
Specific gravity (from wikipedia):
VG = 1.26
PG = 1.04
Your measurements:
Initial = 1.09 (too light for 50/50 liquid)
After boiling = 0.89 (too light for either component)
Difference = 0.2. Too much. It's like liquid went from (almost) pure VG to pure PG.

In tank quantitative changes should be different, but qualitatively it should be the same.

 

[mikepetro]

Found good sized puddles of what felt like VG on the stove. It struck me as odd as I was being EXTREMELY careful and I knew I didnt spill any.

Come to find out, it was condensing in the exhaust hood and dripping back down onto the stove.

 

[mikepetro]

Very interesting. And as expected it became lighter after boiling (specific gravity decreases). But something wrong with your volume/weight measurements.
Specific gravity (from wikipedia):
VG = 1.26
PG = 1.04
Your measurements:
Initial = 1.09 (too light for 50/50 liquid)
After boiling = 0.89 (too light for either component)
Difference = 0.2. Too much. It's like liquid went from (almost) pure VG to pure PG.

In tank quantitative changes should be different, but qualitatively it should be the same.

Yeah, I dont think I did the stovetop volume measurements very precisely. I only used a beaker to measure the 150ml at the stove, and to measure the result after. Had to make judgement calls in between the 25ml increments. Should have used a graduated cylinder instead.

 

[mikepetro]

OK, so I really really wanted to see what the water did to the boiling point

I stopped at 450 as it was obvious it was going to keep going just like the 50/50 did.

 

[Lessifer]

I agree, I would suspect the amount of distillation will be relative to the surface area that is being heated with respect to the total volume.... and time. A pot on a stove wont reflect a coil in a tank beyond showing that the phenomena exists.

Just wanted to say that I hope you understand that my interjections like that are not necessarily meant for you, or to be snide. A lot of people are reading this thread, maybe not all of it, and I just like to bring things back from the theoretical and tangential so that people don't start jumping to conclusions. I really do appreciate the work you're putting in here and I think, even at this "amateur" (even though I don't consider you an amateur) level is expanding our knowledge as a whole.

 

[mikepetro]

As I said earlier "psuedo science" in the lack of real science......

 

[David Wolf]

I've taken for granted that a properly designed TC board would be relatively accurate. The type of topper one uses, heat flux, how long of a draw, repeated draws and temps needed to vaporize different mixes are the issues I am getting a better understanding of. I may never use a TC setup, but there is much here for me to draw on to make my preferred setup safer.

With the current dominance of high VG liquids and VG having much lower volatility than PG or water, I can see that TC is very important in that situation. For me, with 2/3 PG and 5% water, I'm thinking that as long as I am vaping at low wattage (very low by today's standards), keep my draws fairly short and not consecutive, that I am likely not reaching or exceeding 400F.

Anybody who's interested in knowing more about their vape than simply "avoid dry hits" has much to gain in this thread. Thanks for putting in the time Mike!

I'm curious as to how adding 5% water affects your vape with 2/3 pg. any increased leakage? Any effect on flavor etc? I vape 80% PG and have been thinking about adding water (and may a drop or two of citric acid 10% solution) to lower the PH.

 

[Eskie]

I'm curious as to how adding 5% water affects your vape with 2/3 pg. any increased leakage? Any effect on flavor etc? I vape 80% PG and have been thinking about adding water (and may a drop or two of citric acid 10% solution) to lower the PH.

Why do you want to drop the pH?

 

[mikepetro]

I'm curious as to how adding 5% water affects your vape with 2/3 pg. any increased leakage? Any effect on flavor etc? I vape 80% PG and have been thinking about adding water (and may a drop or two of citric acid 10% solution) to lower the PH.

I use the citric acid, it takes the bite off my high nic levels.