I suggest a yard stick for better consistency.It would take a pretty accurate "ruler" to measure the oxide thickness wouldn't it? [emoji38]
Wait
What are we mixing?
Tapatyped
I suggest a yard stick for better consistency.It would take a pretty accurate "ruler" to measure the oxide thickness wouldn't it? [emoji38]
Or the inverse (such as in mech and sub ohm vaping) how higher power actually translates in to more lag time as opposed to higher surface temperatures.I agree with the scale being minuscule at best, but the number of cycles can get really high. The amount would certainly seem to be extremely limited but no one has every actually tested to see what the amount really is in real world vaping conditions, especially like what we see today with the proliferation of sub-ohm, high powered (relatively) devices currently available being used by people that have no concept at all of what power levels are involved.
I agree with the scale being minuscule at best, but the number of cycles can get really high. The amount would certainly seem to be extremely limited but no one has every actually tested to see what the amount really is in real world vaping conditions, especially like what we see today with the proliferation of sub-ohm, high powered (relatively) devices currently available being used by people that have no concept at all of what power levels are involved.
Right, that's the real question we'd all like answered: What's in the vapor we're inhaling?
Metallurgists can speculate that there's no way that metals can get into the vapor. Medical doctors can say that we don't know and shouldn't take "unnecessary risks".
So how about we actually find out? How difficult/costly can it really be to collect some samples and get them analyzed?
I'd be willing to put up every dollar I've saved by not smoking cigarettes in the past 530 days (currently over $6k) to get some actual empirical data. Unfortunately, I have no idea where/how to start.
Guys, regarding nickel and titanium, am I understanding correctly now that oxidation is actually needed to "seal" the metal so that no metals are inhaled? A reason more to dry burn?
What you always wanted to know about that thin initial layer but were too hesitant to ask ...This happens whether you dry burn or not. Dry burn (heating) does speed up the process of forming that initial thin layer.
"God does not play dice" Albert Einstein
I am not a scientist and I didn't even stay at a Holiday Inn last night. I was however raised by a PHD in chemistry and have worked in a University environment most of my working life. You have to understand that when a bunch of PHDs get together to debate/collaborate that sometimes somebody's *** might get shivved by slide ruler in the process. It ain't pretty to the outside observer, but it is what it is. Let them do their thing, at the end of the day we will all be better off for it. These guys all obviously share a passion for vaping and metallurgy and they all have good intentions. Personally I have learned quite a bit from reading this entire thread from start to finish, and I now have more actual reliable information that I can use for my benefit as does everyone else who is following this thread. Carry on Spartans...
Guys, I have a technical question regarding oxidisation layers and contact coils. It's not particularly related to safety so feel free to ignore it as OT, but it is brief and tangentially related to topics under discussion. (Apologies if it's been covered anywhere, I did read every post up to around page 22 but only sporadically since then.)
My understanding is that contact coils are possible with Kanthal because of the oxidising layer that gets formed on them during dry burning. This is why we see inconsistent heating across the coil until we tweak it and it has had a chance to form a consistent layer, which then protects it from shorts between coils.
My question is - why does this same layer not prevent shorts between the coil and anything else? For example, why do I still get shorts if my coil touches any part of the atty base or chimney? Should these not be prevented in the same way?
Or is it that even the slightest brush against any part of the atty will rub off that very thin layer of protection? But if so, I don't understand why we can tweezer/screwdriver a coil and generally pummel it about and it remains workable as a contact coil but then shorts immediately against the atty itself (or indeed against that same screwdriver if one accidentally hits fire while it's still in contact with the coil - not that I've ever done that, of course...)
TIA!
(Red and bolding is my editing)
Materials science is way out of my physics scope so I cannot answer the question, but there appear to be members here whom should be able to answer this question in some form.
Now that one is in my wheelhouse. Because the voltage potential between coil wraps is very small compared to the potential between the coil and the atty base / cap etc.
I think some of the critical questions are: who is going to conduct the study, what sort of vaping rig are they going to investigate, and from where are they going to receive their funding? It seems as though many of the people participating in this thread are concerned with "rebuildables" in their various forms. I would suggest that we are a (growing) minority, but one of only minor concern in the larger e-cig debate. And thus we are of little concern to most researchers who must demonstrate the "relevance" of their work in order to acquire funding. Cartos and such are more complex and introduce many material variables into a study, but they address the concerns of legislators and Big Tobacco, who wish to ban vaping except with "closed" systems. Ideally, from our perspective, a health research professional with expertise in inhalation toxicology or a related field, with support from the vaping community (CASAA?), the organic chemistry community, and the high temperature oxidation/corrosion metallurgy community, would undertake a study which is properly posed. In my mind, the question is this: what "chemicals of concern" are emitted from a rebuildable vaping mod for a variety of coil materials and different thermal exposures? This would mean the correct alloy wires, appropriate wicking materials, appropriate vaping liquids (including flavor components, which can have different corrosion characteristics than a simple PG/VG mix), relevant voltage/current cycles, and the correct analytical techniques to identify all of the elements/compounds of concern and their actual chemical state (chromium is a totally different beast in its difference oxidation states).
What we are looking for is no small task. It's important to us, but I'm not sure it's important to the world at large. We may just have to figure this out for ourselves to our own personal level of comfort/satisfaction. And we need to recognize that, in doing so, we will have little or no impact on the feces-storm brewing globally which threatens to take away our right to vape.
Welcome to life on the frontier.
Maybe a little further explanation. The oxide has a dielectric breakdown voltage. When this voltage is exceeded the resistance declines in the oxide at the breakdown location causing a runaway effect down to a certain resistance. Since the metal in the coil is low resistance the voltage drop between adjacent coil wraps is smaller than the breakdown voltage, but the voltage between the coil wrap (except at maybe the ground potential end of the coil) and the atty is high enough to cause breakdown.
Wife is calling me for dinner.........
Guys, I have a technical question regarding oxidisation layers and contact coils. It's not particularly related to safety so feel free to ignore it as OT, but it is brief and tangentially related to topics under discussion. (Apologies if it's been covered anywhere, I did read every post up to around page 22 but only sporadically since then.)
My understanding is that contact coils are possible with Kanthal because of the oxidising layer that gets formed on them during dry burning. This is why we see inconsistent heating across the coil until we tweak it and it has had a chance to form a consistent layer, which then protects it from shorts between coils.
My question is - why does this same layer not prevent shorts between the coil and anything else? For example, why do I still get shorts if my coil touches any part of the atty base or chimney? Should these not be prevented in the same way?
Or is it that even the slightest brush against any part of the atty will rub off that very thin layer of protection? But if so, I don't understand why we can tweezer/screwdriver a coil and generally pummel it about and it remains workable as a contact coil but then shorts immediately against the atty itself (or indeed against that same screwdriver if one accidentally hits fire while it's still in contact with the coil - not that I've ever done that, of course...)
TIA!
Right, that's the real question we'd all like answered: What's in the vapor we're inhaling?
Metallurgists can speculate that there's no way that metals can get into the vapor. Medical doctors can say that we don't know and shouldn't take "unnecessary risks".
So how about we actually find out? How difficult/costly can it really be to collect some samples and get them analyzed?
I'd be willing to put up every dollar I've saved by not smoking cigarettes in the past 530 days (currently over $6k) to get some actual empirical data. Unfortunately, I have no idea where/how to start.
Here, here, your best and most educational post IMO. You hit on the real current issues, and thus problems. A GREAT read for all concerned. The fact that as of now we have to debate the science amongst ourselves and other vapors is truly a sad state of current affairs. I'll state the obvious, we all know, it almost always ends up being about the dam money, and so far we are holding the short end of the vaping stick.