Boden
Aspie polymath
No worries.
I think more heat is being picked up by the air passing over those little round cutouts in the bottom of the cup than most realize.
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Arizer portable heater tech discussion
- Thread starter stickstones
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I think more heat is being picked up by the air passing over those little round cutouts in the bottom of the cup than most realize.
Andreaerdna
If God is the answer, then the question is wrong
Boden
Aspie polymath
Air II
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TheWhisper
Well-Known Member
KeroZen
Chronic vapaholic
It's been over 9 months since my previous post... that "short while" turned into a lengthy one! I completely forgot about this thread.
A lot of interesting points were made in the mean time. Thanks to all who got the ball rolling!
I don't have any definitive answer, and this thread wouldn't be 4 pages long if it was trivial!
Upon inspection, it seems clear that the designers purposely restricted the air-flow by using very narrow channels, thus increasing metal/air contact time in the process. But most "conduction" vapes work better when you reduce the airflow. See, the Ascent for instance is way too open and you have to create the restriction yourself by drawing ridiculously slowly (so much that nobody excepted me was able to get vapor from this vape in my surroundings!)
I don't know though if the increased contact time with incoming air (and thus higher convection) is just a happy side effect of trying to leave enough time for conduction to happen (as conduction is slow through glass and inside the load, being mostly insulators as we've seen) or if it's a deliberate attempt to add some convection.
What I know for sure is that the heater design is different from the Ascent and FlowerMate(s) that I own, which are to me perfect text-book examples of conduction vapes. Hence it's expected to see it behave differently.
At a rapid glance it would seem though that the surface area is too small to heat much air. But the 550°F figure coupled with a very slow flow rate due to the tight restriction could well prove us wrong indeed.
You are right, I'm embarrassed! I had a brain fart it seems and yes ideally the heatsink/radiator should be painted black too to maximize radiation (higher emissivity), as well as the inside of the case.
What led me astray is the fact that most modern CPU coolers are shiny aluminium and/or copper. And we find a very interesting explanation in this wikipedia page (go to the "Surface color" section) that I'm sure will pour some extra oil on the fire:
https://en.wikipedia.org/wiki/Heat_sink
"Heat transfer by radiation is a function of both the heat sink temperature, and the temperature of the surroundings that the heat sink is optically coupled with. When both of these temperatures are on the order of 0 °C to 100 °C, the contribution of radiation compared to convection is generally small, and this factor is often neglected. In this case, finned heat sinks operating in either natural-convection or forced-flow will not be affected significantly by surface emissivity."
It's interesting also because it goes in the way of what you've been telling us for years about radiation and the need to have a very large gradient for it to be of significance. That being said, with that 550°F figure vs a room temperature load, I think we got such a large gradient initially. If radiation has any effect in our vapes, it appears it must actively contribute mostly only during the lower part of the heating curve, and once that difference drops, other heat transfer methods must become predominant.
Beware that both on the FlowerMate's and the Ascent for instance, the heating element is entirely around the ceramic bowl walls and there's absolutely nothing under the bottom of the bowl. Yet you sitll need to tamp the load down such that it makes contact with the bowl floor, otherwise vapor production is poor (happens when the puck rises when you draw too hard for instance, as soon as you push it back vapor production restarts)
Anyway this must be taken into account when positioning the probe in the various models under test.
That's an interesting data point. I must admit it makes me more hesitant about this whole story. I wouldn't have thought the difference between the element and the cup would be that high. And 550°F is clearly hot enough for a pure convection vape heating element.
This is where I have to disagree. Having built quite a lot of heating elements for "on demand convection" vapes where there's no doubt we're really talking about mostly convection and conduction/radiation is pretty limited, I know with certainty that the element doesn't need to be glowing to produce massive vapour.
It's a matter of wire gauge and above all surface area. RBT high surface area mesh heaters don't need to glow for instance. All coils I built with wires between 18 and 22ga didn't glow at all. The Project stock coils barely glow at high temperature, and you see if only in a dark room when not drawing.
So I don't think the heating element has to be that high in temperature for convection vaping (and actually I think it should be avoided and it's detrimental, mostly for oxidation and heater element longevity concerns, but we're getting off-topic already)
Now it's clear that in Arizer case the surface area is super small... but again the flow is also ultra slow in comparison to on-demand convection vapes which tend to be super open.
This is why you need to tamp tightly your load with conduction vapes. It gets rid of most air pockets and increases the contact surface area, both with the bowl walls and also between plant bits. But I still think it's more important than radiation once the bowl is near vaporization temperature.
This leads me to where I thought I would end when I made my post 9 months ago! I wanted to analyze the "inverse" scenario: with arizer heaters, we are wondering whether the added convection is of any significance in a mostly conduction setup. I wanted to contrast that with for instance the Milaana and Zion, which are nearly entirely convection and examine whether the glass stem added some conduction to the mix. This is why I started the talk about materials conductivity constants etc.
So the postulate is that it appears in the Mi and Zi that there seems to be a natural temperature upward stepping happening. Without varying their heater power, you can extract higher and higher in temperature without altering significantly the trigger time.
At the end of a session the tip of the glass stem (ie the bowl) is hot, sometimes uncomfortably so, but never instant burning hot. I'm assuming it's never above 100°C (boiling water temp) It's not conducting heat to the load unless it's hotter than the load. Rather it's conducting heat out of the hot incoming air stream, and as well as the load once it's at vaporization temperature.
When the air stream stops, the load cools down quicker than the glass. I've never been burnt by ABV, it's lukewarm as soon as you remove the stem. The glass is hotter for sure. At this point the glass must be conducting some heat back to the load, but not enough to vaporize.
So is conduction happening? Yes, but conduction cooling (by convection) Is it significant? It's not enough to produce vapor but it is to the vaporization experience: progressively the stem robs less and less heat out of the system as it gets hotter. That extra heat which is now free gets to the load instead, and I think this is what creates the apparent temperature stepping up. In a way this is "heat soak" in the context of convection vaping no?
Back to the arizer case, I'm not entirely convinced that the added convection would be enough to vaporize on its own. The bulk of the energy is in the cup and moves through the glass too. But in a similar way, heating the incoming air means it will rob less heat out of the system.
To finish here's an interesting "case study" that should offer some food for thought to some (and confirm that metal stems should cool vapor more than glass ones) >> https://www.quora.com/Thermodynamic...ss-Which-of-the-cups-will-cool-faster-and-why
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Andreaerdna
If God is the answer, then the question is wrong
You seem to enjoy eating a lot, 9 months would be enough to eat a whale 
Trying to accept the mainly conduction thesis I always crash against few nonsense guard rails:
- a mainly conductive regulated oven where the heating surface (without any software/hardware detecting the hit) rise in temperature while hitting (convection) and drop back considerably as soon as there is nomore air moving by the sistem (which is almost the definition of convection heat transfer) before starting to rise again way slower
It was not a really a trivial question, it helps to know each others
For me a mainly conduction/radiation hybrid device is vapman or vapcap.. apollo and solo are on the otherside of the hybrid spectrum IMO, towards convection
taste is a very valid meter too, you have a good one IIRC.. now that i checked detail of your sig it seems you never owned-tested a solo-air, is this true? Taste is deliciously fresh and grassy first couple of hits of a solo
Trying to accept the mainly conduction thesis I always crash against few nonsense guard rails:
- a mainly conductive regulated oven where the heating surface (without any software/hardware detecting the hit) rise in temperature while hitting (convection) and drop back considerably as soon as there is nomore air moving by the sistem (which is almost the definition of convection heat transfer) before starting to rise again way slower
It was not a really a trivial question, it helps to know each others
For me a mainly conduction/radiation hybrid device is vapman or vapcap.. apollo and solo are on the otherside of the hybrid spectrum IMO, towards convection
taste is a very valid meter too, you have a good one IIRC.. now that i checked detail of your sig it seems you never owned-tested a solo-air, is this true? Taste is deliciously fresh and grassy first couple of hits of a solo
Cheesequake
Free Men Don't Ask
Taste from my Solo and Milaana (real full convection, or at least as close to it as possible) is night and day different. Milaana is much tastier.You seem to enjoy eating a lot, 9 months would be enough to eat a whale
Trying to accept the mainly conduction thesis I always crash against few nonsense guard rails:
- a mainly conductive regulated oven where the heating surface (without any software/hardware detecting the hit) rise in temperature while hitting (convection) and drop back considerably as soon as there is nomore air moving by the sistem (which is almost the definition of convection heat transfer) before starting to rise again way slower
It was not a really a trivial question, it helps to know each others
For me a mainly conduction/radiation hybrid device is vapman or vapcap.. apollo and solo are on the otherside of the hybrid spectrum IMO, towards convection
taste is a very valid meter too, you have a good one IIRC.. now that i checked detail of your sig it seems you never owned-tested a solo-air, is this true? Taste is deliciously fresh and grassy first couple of hits of a solo
Andreaerdna
If God is the answer, then the question is wrong
Clean stem, temperature @3-4, first hit is almost pure convection to me, later on starting on third hit i agree with you but first one and second one are almost as grassy as a log or anyother pure convection device IMO
Edit, @Cheesequake i do tamp the load against the glass screen so it is few mm away from the cup, as per arizer instructions
Edit, @Cheesequake i do tamp the load against the glass screen so it is few mm away from the cup, as per arizer instructions
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OF
Well-Known Member
Gentlemen,
Please let me suggest a couple of experiments? First, load a stem and insert it into a hot Solo/Air/ArGo and let it 'heat soak' for say 90 seconds with your thumb over the MP (zero convection). Then try a hit that is 'only conduction'.
Then insert a cold stem into the unit, but stop short of the cup (much easier to do with ArGo due to the seal). Puff away for a while, using 100% convection with no conduction.
What do you find? Why do you think that 'conduction with no convection' makes normal vapor and 'convection with no conduction' doesn't?
A couple weeks back we had a new poster on the ArGo thread that performed this experiment. That is he inserted his stem 'most of the way' and got very disappointing results with maximum temperature. So he sent the 'defective unit' back for exchange. Then exchanged the replacement for the same sin, and in true dedication did so with the third? He posted his disappointment and within minutes a fellow Member suggested the error and our new found friend became a happy camper.
I understand guys want their vape to be convection, since they 'know it's superior', but vapor is vapor how the heat gets there is not only not important but technically not possible to determine by the vapor produced. It's just calories. Or BTUs if you're British. Guys get cleanness, early evaporation of lighter fractions and a bunch of other stuff confused in there I think.
Regards to all.
OF
Please let me suggest a couple of experiments? First, load a stem and insert it into a hot Solo/Air/ArGo and let it 'heat soak' for say 90 seconds with your thumb over the MP (zero convection). Then try a hit that is 'only conduction'.
Then insert a cold stem into the unit, but stop short of the cup (much easier to do with ArGo due to the seal). Puff away for a while, using 100% convection with no conduction.
What do you find? Why do you think that 'conduction with no convection' makes normal vapor and 'convection with no conduction' doesn't?
A couple weeks back we had a new poster on the ArGo thread that performed this experiment. That is he inserted his stem 'most of the way' and got very disappointing results with maximum temperature. So he sent the 'defective unit' back for exchange. Then exchanged the replacement for the same sin, and in true dedication did so with the third? He posted his disappointment and within minutes a fellow Member suggested the error and our new found friend became a happy camper.
I understand guys want their vape to be convection, since they 'know it's superior', but vapor is vapor how the heat gets there is not only not important but technically not possible to determine by the vapor produced. It's just calories. Or BTUs if you're British. Guys get cleanness, early evaporation of lighter fractions and a bunch of other stuff confused in there I think.
Regards to all.
OF
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Used2use
Sometimes to stupid to become a fool
To quantify the radiation energy, the physical maximum would be after the Stefan-Boltzmann law:
P= A * T^4*Boltzmann constant
for the cup bottom @250C(523K):
(2*pi*0,006^2)*523K^4*5,67E-8 = 0,95 W
Arizer doesn't use black bodys as heater afaik
so in reality it's less...
With wien's displacement law the max peak emmision wavelength is ~5,5 μm at which the transmission of Borosilicate is zero, so the metal sidewalls of the heated cup don't add radiation to the load.
The hot glass bowl will also emit some radiation energy, but over the thumb it's also less then 1w...
P= A * T^4*Boltzmann constant
for the cup bottom @250C(523K):
(2*pi*0,006^2)*523K^4*5,67E-8 = 0,95 W
Arizer doesn't use black bodys as heater afaik
so in reality it's less...With wien's displacement law the max peak emmision wavelength is ~5,5 μm at which the transmission of Borosilicate is zero, so the metal sidewalls of the heated cup don't add radiation to the load.
The hot glass bowl will also emit some radiation energy, but over the thumb it's also less then 1w...
OF
Well-Known Member
All true. For practical purposes IR has no contribution here. Guys, I think, like to suggest IR since it's another route potentially. Different than the 'inferior conduction' mode. But to work (deliver useful heat energy) the source has to be much hotter than the load. IR works both ways, the load is also heating the source (hopefully at a lower rate) and 'everything else in the neighborhood'. This means in cases like Solo or Vapman, where the source is 'vaping hot' (say 390F), once the load reaches that same (working temperature) THE NET HEAT TRANSFER IS ZERO? The load heats the walls and floor as fast as the floors and walls heat the load. No net transfer.
To get net transfer into the load the source has to be much hotter. Much. The only real IR vape I own is the Bender from Delta 9. There the load is packed around the central rod (heat source) which is incandescent when working. Seriously 'glowing hot', much much hotter than the load. Much like convection needs air heated much hotter than 390F to supply useful heat energy to the load and still be above 390F as it leaves. There too, the rate of heat transfer depends on a large delta (difference in heat) to be useful.
Vapman is, in the end, a straight conduction game as has been 'worked out' on that thread. However it can lead to outstanding vapor all the same? Heat is heat. Conduction calories aren't any different than convection when it comes to providing the heat for making vapor.
Regards to all.
OF
maybe you can help me understand the heat transfer dynamics ... specifically:
what is the equation that quantifies the heat transfer from the surface of the heater to the incoming ambient airflow?
i try to find this every once in a while, but with no success. i did find a calculator that will give me the surface area of my cylindrical heater and the volume of air rubbing against the heater surface, and i know the temperature at the surface, and i know the temperature does not drop with airflow, so it should be pretty straight forward, eh?
i guess i'm looking for watts per cc of airflow per second, or something like that. i do know that a slower draw is better than a faster draw at producing vapor.
due to the small scale geometry of my heater i don't have to run the temp at 500°F to deliver 400°F to the load of herb - i run it at 400°F.
KeroZen
Chronic vapaholic
I imagine the equation on the bottom of that page would be a good start for the convective part >> https://en.wikipedia.org/wiki/Convective_heat_transfer
But since your heater is around a glass core, which itself houses a glass vial... it's probably more complicated in practice.
I'm sure @Used2use could help you further!
But since your heater is around a glass core, which itself houses a glass vial... it's probably more complicated in practice.
I'm sure @Used2use could help you further!
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OF
Well-Known Member
I imagine the equation on the bottom of that page would be a good start for the convective part >> https://en.wikipedia.org/wiki/Convective_heat_transfer
But since your heater is around a glass core, which itself houses a glass vial... it's probably more complicated in practice.
I've been thinking about this for a while now, off and on, and I think the simple answer is 'there's no simple answer'? Entirely too many important variables, as KZ suggests. Over the years I've actually been paid to investigate this sort of stuff with various products for different companies. Surface effects play a huge role, dust in one case caused a roughly 'two to one' change IIRC. That is a unit that failed again met spec when we cleaned the heatsinks. Airflow at the surface also plays a huge factor. You can find big changes as you change fan (airflow) speeds, ironically sometimes more flow means less transfer! We rented a big buck air flow meter that used a self heating thermister on the end of a 1/8 inch SS probe with slots in the tip. Ended up buying a new probe when 'one of the guys' tripped over the cable and bent the tip badly in fact. Airflow at the surface can go down 'in strong wind', sometimes.
All is not lost, however, you can measure this fairly accurately 'in situ'. That is with your exact configuration. Monitor power (heater current times resistance) at equilibrium with no air flow. This represents 'heat losses' (mostly conduction) at the controlled temperature. Then apply airflow (hit it) and measure the new power once it's again stable. The temperature of the heater is the same, the difference in power was transferred to the air? When I've done this in the past we 'pulsed' the airflow, allowing it to cool again to equilibrium after the temperature overshoots when the flow stops. Once power is stable again, again start the flow (again leaving time for it to reach the new equilibrium. 3 time constants is what we used, I recommend starting there.
Good luck with it.
OF
Used2use
Sometimes to stupid to become a fool
Yes, i'm afraid there is no 'simple' equation as there is no 'one' temperature, it's more about flow fields, resistances etc - Navier Stokes equations would be the analytical aproach, but even there it's only solvable numeric and not absolute (differential equations even god can't solve ).
So best way to look deeper into that is CFD simulation eg OpenFOAM is pretty decent and freeware... autodesk has a nice overview of used equations here
).So best way to look deeper into that is CFD simulation eg OpenFOAM is pretty decent and freeware... autodesk has a nice overview of used equations here
OF
Well-Known Member
Or adopt the Brit philosophy: "Suck it and see"? A bit of experimental data from the real world is often more useful than a huge pile of good ideas of what should be.......
OF
KeroZen
Chronic vapaholic
I like your subtractive approach @OF: measure power at equilibrium, with the PID working and regulating to the set temperature. Let enough time for ample heat soaking and to reach a real equilibrium, with no air flow *and* no stem nor load inserted.
Then insert a stem + load and measure the power difference. That first figure should be already of significance somehow. Maybe try to see if you reach a second equilibrium and also note down that value.
And ultimately measure with a steady draw (i.e. forced air flow)
PS: I have a gizmo from my RC hobbies called a "Watt's up" that can measure higher currents than your average DMM >> https://www.rc-electronics-usa.com/watt-meter/watts-up-meter.html that could help you also if your heater resistance is not constant (but you are using Nichrome right? so it shouldn't vary much I think)
PS2: there are Wattsup clones on Hobbyking I think...
Then insert a stem + load and measure the power difference. That first figure should be already of significance somehow. Maybe try to see if you reach a second equilibrium and also note down that value.
And ultimately measure with a steady draw (i.e. forced air flow)
PS: I have a gizmo from my RC hobbies called a "Watt's up" that can measure higher currents than your average DMM >> https://www.rc-electronics-usa.com/watt-meter/watts-up-meter.html that could help you also if your heater resistance is not constant (but you are using Nichrome right? so it shouldn't vary much I think)
PS2: there are Wattsup clones on Hobbyking I think...
OF
Well-Known Member
Can't claim the idea, pretty standard technique in a narrow bit of technology. Establish a baseline without the change then subtract that from the total. I'd do it with the stem/load in. The load makes no difference at constant temperature, but the stem will add some conductive loss I think?
Small world, I've got one of those somewhere (although I changed the cables to 5.2mm Coax). While I tend to be more 'old school', collecting and computing data 'the hard way' it should do fine. The key I think is to cycle the flow on and off and watch the time constant of the change. Use several such cycles to get your answer.
Thanks for playing along. There are only a few of us who are really concerned about such details, which is how it should be IMO.
OF
OF
Well-Known Member
While enjoying my Solo II a bit ago, I think I have an insight to part of the confusion/misunderstanding going on around the conduction/convection topic. It's a bit long winded, but if you're interested in such things please follow along? TIA
First off, to set the record straight, what we commonly call "vapor" is not, it's an aerosol (important difference as you soon see I hope). Vapor is a gas, individual molecules often in a mixture with other (gas) molecules. As is our case. You cannot see vapor since all common molecules are much smaller than the wavelength of the light your looking with. Vapor, true vapor, is invisible. Water vapor in the air ('Relative Humidity') and 'alcohol on the breath' of your favorite drunk being examples.
Aerosols, OTOH, are 'clumps' of molecules suspended in gas. Fog and clouds are examples. As is steam under some but not all conditions. "Live steam" (very hot) is not visible, but as it cools the vapor condenses and we see the 'clouds of steam'. Hold that thought for a bit, please.
A pan of water making dinner (say rice?) on the stove at a simmer is an example of what we have in our vapes. Water vapor, individuals molecules, get separated from the rest when the (heat) energy is high enough. They change from liquid to gas (real vapor), taking energy to do so. But if the pan is covered (no air flow) the vapor simply cools elsewhere and condenses back in to visibility, eventually 'raining' back into the pot. The total amount of water doesn't change since none escapes the system.
If you remove the cover, and the action is low enough to not create convection issues, you find a 'layer of steam' trapped withing the pan? It is 'boiling temperature' (212F unless you use that newer system.....) everywhere. Now blow a bit of colder air in, what happens? Yep, a big 'burst of steam'? What we see, is the effect of COOLING the vapor. The cooler air cannot hold as much vapor as when hotter (the basis of Relative Humidity). Fog happens in the morning not because heat is being added, but rather because the air is cooling off from lack of sunshine and can no longer hold as much water vapor (real vapor) and the excess condenses (combines with other vapor) to form an aerosol (fog) we can see. Cooling is necessary to form visible 'vapor' (aerosol), otherwise it 'recycles' inside the vape.
This 'cooling the vapor to condense aerosols' releases the heat that originally formed the vapor from liquid (often called 'latent heat') in the first place. This is why foggy mornings are warmer than dryer ones where no fog is formed.
This is what I believe we have happening in Solo/Air/ArGo. Vapor forms in the load over time ('heat soaks') but is trapped in being recycled by condensing again. Normally nothing escapes the system. However draw in COOLER air and the ability to hold it all as vapor disappears and aerosols (which we mistakenly call 'vapor') form for our enjoyment. Concentrate vapes like the Divine Tribe Quartz Quest (recommended, BTW) and 'nails' let you see this happen. It's more of less 'sitting there' until you draw a stream of cold air in and generate 'huge clouds' where none were before.
We all know that to 'really milk that glass' you go slow? That's why. Adding a bit of cold air makes the milk, too much flow and it 'thins out'? We can only condense the (real) vapor present into visible aerosol we'll misidentify as vapor. This is, I think, leading to the misunderstanding of the conduction/convection thing for the most part. As vapor is created slowly by conduction we draw it away thinking it's the heated incoming air doing it when in fact it's almost the opposite? The perception is 'if you give the hot air enough time to heat the load, you get vapor'? Mind tricks and not a Jedi in sight........
"Heat soak" is a symptom/characteristic of conduction, where the rate heat can be added is fixed. You don't see it in convection vapes like Vapor Genie or ThermoVapes T1/Evolution/Cera. There, since the heated (to much higher temperatures) air input is bringing more heat to the party you don't see a drop off like with Solo/Air/ArGo. The harder you hit, the heavier the vapor gets. Not the other way about. That (going up, not down) is a convection characteristic.
Anyway, that's what I think is happening, and why. Thanks for listening.
OF
First off, to set the record straight, what we commonly call "vapor" is not, it's an aerosol (important difference as you soon see I hope). Vapor is a gas, individual molecules often in a mixture with other (gas) molecules. As is our case. You cannot see vapor since all common molecules are much smaller than the wavelength of the light your looking with. Vapor, true vapor, is invisible. Water vapor in the air ('Relative Humidity') and 'alcohol on the breath' of your favorite drunk being examples.
Aerosols, OTOH, are 'clumps' of molecules suspended in gas. Fog and clouds are examples. As is steam under some but not all conditions. "Live steam" (very hot) is not visible, but as it cools the vapor condenses and we see the 'clouds of steam'. Hold that thought for a bit, please.
A pan of water making dinner (say rice?) on the stove at a simmer is an example of what we have in our vapes. Water vapor, individuals molecules, get separated from the rest when the (heat) energy is high enough. They change from liquid to gas (real vapor), taking energy to do so. But if the pan is covered (no air flow) the vapor simply cools elsewhere and condenses back in to visibility, eventually 'raining' back into the pot. The total amount of water doesn't change since none escapes the system.
If you remove the cover, and the action is low enough to not create convection issues, you find a 'layer of steam' trapped withing the pan? It is 'boiling temperature' (212F unless you use that newer system.....) everywhere. Now blow a bit of colder air in, what happens? Yep, a big 'burst of steam'? What we see, is the effect of COOLING the vapor. The cooler air cannot hold as much vapor as when hotter (the basis of Relative Humidity). Fog happens in the morning not because heat is being added, but rather because the air is cooling off from lack of sunshine and can no longer hold as much water vapor (real vapor) and the excess condenses (combines with other vapor) to form an aerosol (fog) we can see. Cooling is necessary to form visible 'vapor' (aerosol), otherwise it 'recycles' inside the vape.
This 'cooling the vapor to condense aerosols' releases the heat that originally formed the vapor from liquid (often called 'latent heat') in the first place. This is why foggy mornings are warmer than dryer ones where no fog is formed.
This is what I believe we have happening in Solo/Air/ArGo. Vapor forms in the load over time ('heat soaks') but is trapped in being recycled by condensing again. Normally nothing escapes the system. However draw in COOLER air and the ability to hold it all as vapor disappears and aerosols (which we mistakenly call 'vapor') form for our enjoyment. Concentrate vapes like the Divine Tribe Quartz Quest (recommended, BTW) and 'nails' let you see this happen. It's more of less 'sitting there' until you draw a stream of cold air in and generate 'huge clouds' where none were before.
We all know that to 'really milk that glass' you go slow? That's why. Adding a bit of cold air makes the milk, too much flow and it 'thins out'? We can only condense the (real) vapor present into visible aerosol we'll misidentify as vapor. This is, I think, leading to the misunderstanding of the conduction/convection thing for the most part. As vapor is created slowly by conduction we draw it away thinking it's the heated incoming air doing it when in fact it's almost the opposite? The perception is 'if you give the hot air enough time to heat the load, you get vapor'? Mind tricks and not a Jedi in sight........
"Heat soak" is a symptom/characteristic of conduction, where the rate heat can be added is fixed. You don't see it in convection vapes like Vapor Genie or ThermoVapes T1/Evolution/Cera. There, since the heated (to much higher temperatures) air input is bringing more heat to the party you don't see a drop off like with Solo/Air/ArGo. The harder you hit, the heavier the vapor gets. Not the other way about. That (going up, not down) is a convection characteristic.
Anyway, that's what I think is happening, and why. Thanks for listening.
OF
but is it conduction if there is no physical contact between the herb and the heater? except, maybe, a couple of points of contact, rather than the "mash it down against the heater plate" in the PAX.
OF
Well-Known Member
Good question in general, specific to PAX I've no idea how to start since I've never used one?
The general answer, which includes the subject vapes, is yes. Even a very loose load is heated by conduction. Conduction from the cup to the walls for the most part. That's how heat enters the system, the key point. Eventually everything in the oven gets to the same temperature since there are no losses to drain heat as more and more comes in. As the delta (temperature difference) gets smaller and smaller, the transfer (in calories per second say) goes down lower. Eventually becoming zero at equilibrium. Tight packs move the heat through the load faster (but mean more mass to heat.....) otherwise heated air inside does a lot of the work (just like happens in your oven roasting the holiday turkey?
For convection to work, the air entering the load has to be hotter than the load going in, by a lot if we want lots of energy to make vapor for our enjoyment. Or so the textbooks of my youth preached. Then again, this was pre vape, combustion only, and all good herb came complete with stems and seeds.
Fun stuff.
OF
i suppose radiation is going to function like the contact with the heater surface ... there is very definitely a heat soak required ... i have virtually no contact between the vial and the heater surface - only at the top and bottom circumferences of the vial - really a point contact at top, but the entire rim at the bottom, so at the two ends of the heater - which i have measured to be much less than the middle of the heater coil, which is only 1/2" away.
i do get wisps of "vapor" rising from the vial about 60 seconds after power on - which is 45 seconds after the heater reaches the target vape temperature.
i don't know why i try to make getting high so complicated ... some sort of validation perhaps?
i do get wisps of "vapor" rising from the vial about 60 seconds after power on - which is 45 seconds after the heater reaches the target vape temperature.
i don't know why i try to make getting high so complicated ... some sort of validation perhaps?