Arizer Air II

[OF]

Always some solid advice OF! I just now heard about these soloII and AirII, now to sort out if it's worth upgrading my old faithful solo OG.

Tim! Yer still with us?

They said 'you was hung'.......maybe they were talking about something else......

I kinda lost track of you when you started into that work thing, but you seem to have survived it as well. Glad to hear your Solo is still giving good service. As @ataxian says, 'suckers are too tough to die'. Bad move on Arizers' part, a bit like VW making the Beetles look the same year after year after year unlike the others adding fins and stuff so old cars would look old (by design if not condition) and folks would want to buy new ones. The goal, I'm told, is to last just long enough to get out of warranty.......

I don't have an Air II (yet?) but I do have a Solo II. Perhaps we should try to meet up so you can check it out? That is if you can break away from making all that money......

And between hits I was letting the A2 heat up again (I guess? It doesn't indicate that the oven needs heating up..but I think it needs at least a second or so to kind of get back to the set temperature).

Yep, you broke the code! Of course the temperature drop is sensed (or it would never reheat.......) they just don't want you to worry about it. It's called "masking" in the trade. Watch the temperature rise on many such vapes, they get within 5 or so degrees and then jump to the setpoint being displayed (instead of the actual temperature) and the 'ready to go' light lit (although it's not ready quite yet typically).

But any 'closed loop' system runs on error, how far away from ideal is current performance? If it didn't really sense a drop in heater temperature it would never recover from the hit? This 'disagreement' is often called "Delta" or "deviation" and ability to sense it is critical......they just are kind shy about telling you 'cuz they don't want you to worry.

In vapes like Ascent, which is also masked, you can see there is a huge drop with the hit. Ascent is basically the same thing, a glass lined conduction vape, only the bowl is 'molded in'. That is the heater is ceramic (glazed of course) and the stem and MP rotate over it for use. Air comes in the floor same as Solo/Air. Here's a shot of the bowl:

The thing poking up through the bottom is my temperature sensor (small J/K thermocouple) ending in the plug taped to the outside. It measures the real temperature of the load in the center, independant of the Ascent. When loaded normally and 'fired up' the display shows a great agreement with the unit, amazing almost:

399.9 is close enough to 400 'for a small shop'. But, if I hit it real hard (and get it down and a photo taken fast enough look what happens:

That's right, the center of the load is well below 'magic temperature' even still. It was about 100F too low during the hit. I just recovered half or so of that in the 15 or 20 seconds it took to get the photo.

It has to be since conduction is a slow way to move heat. The cold air and energy taken to make vapor cools faster than conduction can heat.

Notice the unit display still shows 400? Part of that is honest (the sensor just 'doesn't know yet'), some of it is masking but the goal is met their CS department isn't flooded with anxious users worried about the temperature drop. Those with us on Solo I recall angst at 'loosing a light' in a hard hit? There part of the concern was nullified by the heater clicking back on at the same time, explaining what was going on to some extent.

The same harsh rules of Physics apply to both vapes. If the load center in Ascent gets 'heat starved' in a heavy hit, Solo/Air must as well. From a Thermodynamics POV they are basically the same deal. Solo is probably not as sever, but it has to be happening there too?

OF

Edit: BTW the sensor in Ascent is inside the bump on the right end of the bowl bottom. It's in a better position to sense load temperature and respond being further from the heater (which is in the walls and not bottom). By default it has better potential for accurate control because of it.

OF

 

[stickstones]

DISCLAIMER: I AM NO SCIENTIST OR ENGINEER, AND I'VE NEVER PLAYED ONE ON TV. IF YOU ARE, AND YOU CAN FIND FAULT IN THIS TEST, PLEASE POINT IT OUT BOLDLY SO I CAN DO IT BETTER NEXT TIME!

Since we like discussing the heating types used in the Arizer portables, I thought I'd share some test results I got yesterday, which are similar to other tests that have been done on these vapes. Here's a chart showing the heating profile of the Air 2 during a session. The vape was set to 390 and a temp probe was installed in the glass bowl with some hemp fiber. Care was taken to make sure the temp wire wasn't touching the glass walls of the bowl so I could get readings of what is going on inside the load.

I let the vape sit with the stem in place for nearly two minutes before drawing on it, and at this starting point the temp was reading 140F on thermometer. When I started my draw the bowl temp increased dramatically, 165 degrees over the course of my 15 second draw. When I stopped drawing the bowl temp immediately started cooling off, finally stabilizing at around 205F, where it sat until I started my second draw. You can see this pattern repeat 3 times.

The temp setting used was 390, so I don't put much stock in the temp readings (peaked at 320) as much as I do the temp profiles. In other words, I trust the curves, not the numbers, and I see this in a lot of the vapes I test this way. I get good vapor from the Air 2 on 390, so I don't think it's only heating up to 320F. I found the Solo 2 to be nearly 60 degrees off doing a similar test, so this looks pretty normal to me. If you have any idea why my readings are usually lower than what I expect to be actual, please chime in!

The curves tell me there is a decent amount of convection heating going on...more than I thought. Until I see actual evidence to the contrary, I disagree with the conclusion the Arizer portables are only conduction. Instead, they are an elegant way to do a gentle hybrid that others haven't caught on to yet. When I see these curves along with Arizer's short explanation of what is going on, here is how I would best describe it...I hope this is right and if it's not, please feel free to correct:

The ceramic heating element is in direct contact with the metal bowl, which is in direct contact with the glass stem. The heat quickly transfers from the element to the metal, but glass is a poor conductor (it's actually classified as an insulator by many), so the heat transfer slows here to the point where the average user wouldn't notice since many of us are hitting it well before the two minute mark that I did. When the user inhales, air is drawn over the ceramic element, heated up more than the herbs, and sucked through the bowl.

This is different from a classic conduction-only vape like the PAX or Flowermate vapes where the oven itself is heated up and is in direct contact with the herbs. Also, there is no heated air entering the oven. In these units, vapor is generated in the oven and sucked out during a hit, while ambient, unheated air is drawn into the oven.

7th Floor vapes are classic convection-only vapes, and the user can easily overwhelm the heating element since it has a static set point that doesn't compensate for the draw. It's simply set to a certain power point and the user has to adapt to make sure he/she isn't drawing too hard and lowering the temp.

Hybrids are pretty interesting to me. For the most part, the ones I have disassembled mimic what Storz & Bickel does. They have a conduction oven with a convection heating system beneath it. Sometimes manufacturers heat both systems, sometimes just the conduction system, sometimes just the convection system. But at the end of the day they are all some sort of hybrid with different ratios of convection to conduction. Usually when a manufacturer says they are full convection, they are only heating the convection system while not referencing the ambient heat that moves to the bowl to create some conduction.

I call the Arizer system elegant because it is the only one I've seen that uses heat resistance materials (glass) to control the heat in the bowl like they do. So instead of coming up with an electronic solution, they just used the natural characteristics of the materials in the vape to accomplish their goals. Most vapes have you pack the bowl directly, making runaway conduction unavoidable. Ever notice how the only place that scorches in the Arizer portables is the surface of the herbs that touches the bowl? That's because the bowl is hotter than the glass stem. The glass gets hot, for sure, but not as hot as the metal unless it has a decent amount of time to allow the heat to transfer.

I would guess Arizer moved the temp sensor away from the bowl to make it more reactive to the convection needs by reading the heater temp instead of the temp of the heat soaked metal bowl, but this is pure speculation on my part.

I want to stress again that I am not an engineer or a scientist. This could all end up being horse shit. But it's the best I can come up with given the facts at hand. If you see flaws, please point them out! I used to think the Solo was a conduction only device until about two years ago when I ran across some tests like the one done here. At that point I started paying a little more attention to what Arizer was saying and it started to make sense when considered with these test results.

 

[KidFated.]

Damn, Sticks.

 

[thx1138]

thank you @stickstones, thats the most informative work I have seen yet on these vapes - together with the comments on temp reading from @OF - we are all getting a good lesson on one of the best lines of vapes out there

I wonder - if you keep drawing past the already large sized draw you took, would the temp keep going up? I wonder where the ceiling on that is. Also, if you slow the draw, and take a really long one so that the temp spikes and your giving the load time to really heat up, is that then the best way to get the most condensed (milky) hit off these? I know that seems obvious but this chart suggests to me that the Air 2 (and probably the Solo 2?) spike the heat in a way similar to my Pax 2. Just questions generated from all that good data.

 

[OF]

Great graph! Shows what I found on Ascent I think. You can see the rapid recovery between hits ("heat soak"), something like six seconds (1/3 of the box which is 18 seconds wide). Fits with observations? Cool.

Also you can see a 'floor' for the drop where equilibrium is reached where heat input via conduction balances against heat loss by cold air? The two different 'floor values' being different draw rates?

I'm not so sure vapor production is a factor here? If that temperature scale is accurate we're too cold?

Fun data, thanks.

OF

 

[stickstones]

If that temperature scale is accurate we're too cold?

I'm not sure what I'm doing wrong here, but I'm doing it consistently! Almost every vape I do this with reads lower than expected, so I'm getting used to it, but I don't like it. I'm open to help on this one!

Also you can see a 'floor' for the drop where equilibrium is reached where heat input via conduction balances against heat loss by cold air? The two different 'floor values' being different draw rates?

I'm not sure about this, but I think you might be reading the chart wrong...I'm working a headache and a lot of work details today...sorry! But here's what I did...my draw is happening on the upclimb, and the cool down is between hits after my draw. So cool air is never drawn into the bowl, just hot air. It is heating up rapidly when I start to draw, and then starts dropping as soon as I stop my draw, stabilizing around 200ish until the next draw. Does that make sense? I hope I'm explaining it right, and I'm probably reading your post wrong!

Back to work...I'll probably make a lot more sense after my work day...

 

[OF]

I'm not sure what I'm doing wrong here, but I'm doing it consistently! Almost every vape I do this with reads lower than expected, so I'm getting used to it, but I don't like it. I'm open to help on this one!

That sounds like a classic 'instrumentation error' in such things. In such cases heat is conducted up the (metal) leads quite easily making the temperature of the metal lower than it should be. Thermodynamics again, the flow of heat up the wires impacts the heat transferring into the T/C through the load. Like leaving the spoon in your tea so it can cool faster.

Lead diameter can effect this. A classic way to detect it is to try very fine (say .003) leads rather than more normal, thicker, ones. A higher reading points to a problem, and even the thinner ones can't be trusted (you need 'zero thickness'?).

It's easy to do a useful 'two point' calibration. Stick the probe in ice water (has to have solid ice and be stable) for a couple of minutes, then boiling water for a bit. You need 32F and 212F (or 1 and 100C). BTW, it's a common misconception that the T/C signal comes from the weld, it does not. It comes from the temperature change along each lead, in this case it's not really where you might think for that reason.

I'm not sure about this, but I think you might be reading the chart wrong...I'm working a headache and a lot of work details today...sorry! But here's what I did...my draw is happening on the upclimb, and the cool down is between hits after my draw. So cool air is never drawn into the bowl, just hot air. It is heating up rapidly when I start to draw, and then starts dropping as soon as I stop my draw, stabilizing around 200ish until the next draw. Does that make sense? I hope I'm explaining it right, and I'm probably reading your post wrong!

I think I'm following you but am afraid of what that might mean? You're saying the temperature reported goes UP? That is it's idling happily along between hits and the lot suddenly gets hotter when you hit it? But that's not happening in the real world. At idle the load is at the set temperature by conduction (and turns dark over time to prove it), without hitting.........

As a guess, the heatsinking offset above is 'at fault' here? That is convection really is bringing more heat to the sensor than before (ironically as the load average is dropping) heating it up to a higher temperature.....BUT STILL SHORT OF 400F OR SO NEEDED TO MAKE VAPOR.... Maybe.

If it went up to 400F between hits (as we know is happening due to other observations) I think we'd see only decreases in temperatures.

Fun stuff.

Thanks.

OF

 

[stickstones]

I think we're on the same page now with the graph. Showing off my skills again here...

I think I'm following you but am afraid of what that might mean? You're saying the temperature reported goes UP? That is it's idling happily along between hits and the lot suddenly gets hotter when you hit it?

Correct.

 

[OF]

Correct.

Thanks for the confirmation. I vote Instrumentation Error here. The readings are all artificially low? Worth checking the calibration I guess, but that does seem to explain what we see?

Ironically I can see how it could lead a guy to think it was a convection vape (except the temperatures are too low to make vapor).

There was some discussion a bit ago about rearranging the heater/sensor to favor convection? I'm thinking that kind of a fun idea. If you put a heatsink with lots of surface area between the heater and sensor it should still reach the same steady state temperature as before. However, the cold air being drawn in will cool the heatsink quickly and trigger the heater on early? And the incoming air can pick up at least some heat cooling it meaning less taken from vapor production later on?

Thanks again.

OF

 

[stickstones]

I agree the temp readings are low, but they are consistently low (and I think this is due to something I am doing). The curves are good. They look a lot like this profile I got from an on-demand convection vape I'm beta testing. One might even argue they look better!

You've got the same meter I have, why not run the test for yourself?

 

[OF]

I agree the temp readings are low, but they are consistently low (and I think this is due to something I am doing). The curves are good.

You've got the same meter I have, why not run the test for yourself?

Yes, I agree, it is a problem with your experimental setup. The data is not valid for that reason.

Notice a couple of very important differences with your second graph. First off the temperature reading is very believable. 380F is realistic for vapor, 300 is not. Notice the shape of the curve. A rapid rise (say 5 seconds?) to a peak temperature which decays slowly. As you'd expect.

The first and second curves are radically different, really?

In response to your question, I have a couple of T/C meters. I did try this (although I don't recall with which, not that it matters). I couldn't get past the Instrumentation problem, although it did come out closer with fine leads. I think I reported it here somewhere. It looked like this and gave the same 'temperature reported goes up with a hit' no doubt for the same reasons?

Since I knew the T/C reading was accurate (for what it is), I knew 'something was up' and didn't trust the data. Still don't. I'd hoped you somehow got past this problem but it seems not.

Pity.

OF

 

[stickstones]

The one I'm using doesn't have the ball on the end. So I think I'm using the fine leads like you mention.

My equipment is good...got it from a good source and it worked for him (dude had technical training, unlike myself). Can you give me some tips for how you would run the experiment so I can duplicate it? I want to nail this thing so we get the same results.

 

[OF]

The one I'm using doesn't have the ball on the end. So I think I'm using the fine leads like you mention.

My equipment is good...got it from a good source and it worked for him (dude had technical training, unlike myself). Can you give me some tips for how you would run the experiment so I can duplicate it? I want to nail this thing so we get the same results.

What does your friend say? I agree, the gear is OK, it gave 'believable' temperature readings in the second case. Since the temperature (where vapor is made) is the same in both cases, we have a reporting problem? Ironically it also gets inverted in the process. Fun how that happens (or at least seems to).

I'm not sure what to advise (since I failed.....or at least gave up). You must be using a welded T/C probe of some sort. Many are jacked in a SS (typically) cover. Often with a point. This can be a problem sometimes, which is why the open versions are usually preferred where possible. In a former life when we had to read the temperature of a small 'hot stage' (up to 1200C in some cases!) in a vacuum we'd weld small gauge leads to each side of the block. Block material doesn't matter, it's a short circuit. Both welds are at the same temperature. Both leads cool rapidly (first 1/2 inch or less), again to basically the same temperature and remain more or less matched all the way back to the 'cold reference junction' in the meter. The voltage difference is the measure of temperature with some number crunching. If you make the conductors much heavier you can get a lot of current at not much voltage this way, which is how the safety in your gas heater, oven or hot water heater works if it has a pilot light. The small flame heats a T/C in a SS probe providing current that runs through many turns of a coil building up a weak magnetic field. Strong enough to hold the safety valve open, but not enough to open it on it's own. If the pilot gets blown out the T/C cools and the valve drops out (closes) the gas supply to prevent surprises. Since electromagnets run on "Ampere turns" you can make up for the low levels available in current with more turns around the core. It's the product of the number of electrons running (current) times the number of times around the course (turns) that makes MMF (Magna Motive Force) thus generated becomes Gauss (or Teslas, measures of magnetic strength) when properties of the core and total 'magnetic circuit' are factored in. But the same pathetically small signals we're working with here do yeoman's duty every day in millions of applications.

Fun stuff, but I ran into what I think you're looking at. What good old Heisenberg warned us about? We become part of the experiment, our T/C gauge is altering the experiment too much. There can be no doubt that some of the load is about 380F and making vapor, same as there's no doubt the temperature seen by the herb right around the sensor sees a different reality.

Tough nut. For now defying measure by the skills I have. The technique worked very well with Ascent, not quite so well with the Devine Tribe doughnut carts, but clearly off here and with Flower Mates.

I suspect putting the probe closer to the wall would improve it since it would then get better conduction through the herb (shorter path), but by the grim rules of Thermodynamics heat flow has to be considered. If heat is flowing there are temperature drops. That part always happens to some degree or another. The 'trick' is to be sure both leads (or the bead) are 'on the other side' of such drops. That is connected to the hottest part of interest. In our case there's a drop 'across the herb interface'. And heat only flows 'downhill', from hotter to cooler. Just the metal leads alone would be pulling heat, causing temperature drops from what they should be? Put enough of them in and you'll never make vapor. Consider that the minor effect of this 'heat theft' with Ed's otherwise excellent stems calls for bumping the temperature setting up a step or two to enjoy the same as before.

Not trivial, even with the Web.......

Let me mull it around some, there should be a way to figure this out. Feel free to lose sleep over it as well if you wish.

Thanks again, more 'food for thought'.

OF

 

[stickstones]

Lose sleep, I will, brother!

I did some more things and have come to the conclusion you have in my temp readings...user error of some sort. I actually have two thermometers here, and at least six wires. So I pulled out both thermometers and three completely different wire ends (one closed, one that is split into a pair, and one with a thicker gauge probe that I used to calibrate minivaps.)

Now, when I calibrated minivaps I was provided the proper temp probe and told where to place it, and the results always came out as expected. But now I have no idea where to place the sensor, and I know that makes a big difference from fucking with minivaps.

So today I used all three wires and gave each its own turn shoved through the stem down into the mouthpiece. All three times with no herb or hemp fiber...just air. Every time I got different temp readings...by as much as 20 to 40 degrees. Then I did a test with herb in the bowl to see if that brought it up any...it didn't. It was still in the 250 to 320 range during the whole session, but I was getting vapor as expected, so I know it was working. I also got different readings when touching the bottom of the oven, even at the same time with two different thermometers, so placement is huge here.

I say all that to ask for help in where to place the sensor. Anyone can get in on this, not just me and OF. Feel free to come along for the ride, guys!

The only thing that was consistent across all tests, was that the temp rose when I hit it. Every single time, no matter which thermometer, wire, placement, or bowl contents. It always went up during the hit and went back down afterward. The first hit would see a pretty big swing, and by the end of the bowl it was only a 50 degree swing, with the low point about 10 degrees higher each time.

 

[OF]

The only thing that was consistent across all tests, was that the temp rose when I hit it. Every single time, no matter which thermometer, wire, placement, or bowl contents. It always went up during the hit and went back down afterward.

Yep. From another perspective 'it got closer to the real temperature of the herb' explains that part? Convection (hotter air blowing by) is making that so of course, but not contributing useful energy to make more lovely vapor (not possible at 300F).

Given that, it's what I'd expect to be happening. Stick all those probes together in the same bath (sand and salt are commonly used) for a while and you should read 'exactly' the same temperatures (subject to metal purity). There thermal conduction is much better than the heat lost up the leads buried in the bath. However I don't think we can 'get there' this way. There is a technique where you compare readings with probes of two different thermal conductivity. Like comparing thin to thicker wires and extrapolating to what leads of zero cross section would read. I've never tried this personally, but think that might work??

Perhaps thermocouples are the wrong way to go. Traditional and all, but not 'right'. Perhaps thermisters? That is thermal responding resistors, like used in Solo/Air. In the sort of area we're in they can self heat some and foul things up but there are ways to deal with that. The difference being no work done (as in T/Cs)? Leads are still an issue, so we need a 'micro machine' we can embed with the herb. With a tiny battery and transmitter, of course. Like in the movie. Only microscopic. DARPA likes that kinda stuff, right?

How do you file for some of that lovely free Federal money for useless research projects? This one could answer useful questions........

OF

 

[thx1138]

I think the chart is more informative in giving the response of the unit to a draw on it; those dynamics are all I needed to see - whether you had the temp register correctly is secondary for my needs (probably alot of folks needs too) - as I am sure the amount of vape being produced and the change in terp profiles on known flowers with increased heat settings tells me plenty about the temp.

 

[Hippie Dickie]

it was only a 50 degree swing

this is exactly what i measured in my (convection) vape. i put a BBQ thermometer probe in the middle of the vial, in the middle of some herb, and during a session, the non-toke temp was 50F below the temperature during a draw. it took 5 seconds for the probe to measure the setpoint temperature, matching the BBQ thermometer touching the glass wall of the heater.

my thought: air is an insulator, so when the airflow stops, the probe cools off, by the 50F amount. geometry must dictate the drop ... my vial is 1/2" diameter and sits 0.5mm from the glass wall of the heater.

also, there is a lot of radiant heat from the walls of the heater directed into the vial by the surrounding heat shield, so heat soaking the herb takes about 60 seconds.

and, the temperature of the heater is not increasing 50F in 5 seconds ... that is physically impossible, and i'm using 70A batteries. rather, it is the delivery of the heat to the load that is increasing so fast.

Perhaps thermocouples are the wrong way to go.

i'm sticking with a K-type, since a single chip reads it and converts to temperature, which can be serial clocked into the processor chip. temperature control with 2 chips (and a MOSFET) has got to be as simple as it can get.

uh ... kind of off topic, eh?

 

[stickstones]

Thanks for chiming in, guys...this is fun!

@OF, the temp reading when I had herb in it was too low to create visible vapor, yet there it was. So I interpret that as the problem is the temp reading, not that it is too cool. It gets to 390...I use that temp on every vape I test and I have a good feel for that temp. But I’m not measuring the right point somehow. If you were able to get readings that made sense to you with your rig, let me know what you did and I’ll go at it until I can replicate it here.

@Hippie Dickie - when you say K-type, is that what I’m using or something else? If it’s what I’m already using, then I think I agree. What I’m using is used by engineers and people here like OF. That’s what gets me...if he can get a 390 reading then I should be able to get one also. Then I can run the test with accurate temps and move on in this testing.

@thx1138 - At the end of the day I am with you...it’s a killer vape no matter how much chatter we generate about it here. Most people don’t care how it heats, they just want it to do it well, and this one appears to!

 

[Hippie Dickie]

then I should be able to get one also

your last chart shows that you are getting 390F, 5 seconds into the hit ... but the resting temp will be lower, unless you are measuring the heater itself - i.e. with the thermometer probe in direct contact with the heater ... and in this case, you should see a slight drop in the heater temp during the hit - depending on how fast the PID algorithm responds, and the current output of the batteries.

now, it takes three hits to actually get up to that 390F, perhaps the evaporation of the trichomes absorbs some of the heat delivered, until after 3 hits they are mostly vaped.

and the second hit doesn't get as high as the first hit, because this is where the trichomes have finally gotten heat soaked and open up more (i.e. melt the plant wax) than on the first hit ... so second hit should be denser vapor.

 

[stickstones]

@Hippie Dickie That chart was for a different vape...my apologies for the confusion. For the Air 2, only the first chart applies, or the one with the arrows.

 

[Hippie Dickie]

@Hippie Dickie That chart was for a different vape...my apologies for the confusion. For the Air 2, only the first chart applies, or the one with the arrows.

okay, sorry ... different probe type? thicker or different shroud? thicker leads?

i use a BBQ thermometer for my real world readings, which i take apart to get to the probe element ... it has a small glass covered thermocouple, with thin leads - about 30awg

 

[stickstones]

Here is a heating profile I logged from a pure conduction vape I like, the Flowermate V5.0S. I packed it medium-firm with a Chewy 2.0 grind to the top of the ceramic. I took the metal and ceramic screens out of the mouthpiece and ran a probe, the one with the ball on the end of the wire, into the mouthpiece and stuck it in the oven, aiming for dead center and touching no walls. I then screwed on the mouthpiece and turned the vape on to 395F.

Point Notes:

1 – The therm read 140F and the vape stopped blinking, so I started wiggling the wire until it got somewhere near 390F.

2 – Here it started to make sense so I stopped wiggling the wire. I think the final position of the wire was in touch with ceramic somewhere, most likely on the bottom. The vape eventually stabilized at 400F, and it took a full three minutes, although it would have been fine to hit after two minutes.

3 – Start of first hit.

4 – End of first hit.

5 – Start of second hit.

6 – End of second hit.

7 – You get the idea. Between 6 and 7 the unit timed out and I turned it back on.

8 – At this point I realized my hits were heavy, so I milked it like normal and, to my surprise, it cooled down just as quickly.

My gear appears to be working fine. Not only did the heat profile come out as expected, but the temps read well too. Now I need to figure out where to measure temp on the Air 2 so I can re-run these tests. Suggestions, anyone?

 

[metaknight]

Now I need to figure out where to measure temp on the Air 2 so I can re-run these tests. Suggestions, anyone?

Figured it would be best to check the middle of the bowl, but maybe a little bit closer to the crucible to see what's happening to the toasty bud at the top of the bowl?

 

[stickstones]

Figured it would be best to check the middle of the bowl, but maybe a little bit closer to the crucible to see what's happening to the toasty bud at the top of the bowl?

I've been thinking a lot about this lately. I think it comes down to us using a thermometer that was designed to be used in direct contact with the source being measured, and not an air flow. It reads fine on surfaces and conduction ovens. I don't think it has anything to do with the theory of the probes wicking away heat and distorting the readings...if that were true this design would be faulty in all applications and not just this one. But if that is happening, maybe we can quantify and account for it.

The leads going into the bowl were run through one of the four holes, so they weren't directly in the center. Plant matter is a shitty conductor, so it might have something to do with how long the probe and herbs are in the heat zone. With a conduction oven they are in there full time and getting up to the set temp. With Arizer portables, they hover low until you hit it, and then the bowl retains about 200F of heat. So maybe the herb isn't getting saturated enough to register a full 390, but instead a little lower as vapor is run off. Just a theory here...

As time goes by and I do more testing I am getting more sure of this being a hybrid that is mostly convection. I sent off a set of convection heat profiles from another vape to a manufacturer that said the curves look like their convection profiles, with no mention of the low temp readings. Since I get those same low temp readings on any convection stream I try to measure, I think most are getting these results and they are normal...we just need to know how to make sense of them.

I'll do some more testing, probably over the weekend, on some of my other convection vapes to see how they read. If it turns out all of them are off, hopefully by a consistent amount, we might be able to come to some realistic conclusions about the readings. As I said before though, the curves are trustworthy and the temp readings in question do not invalidate them. Even if I never register 390, it still curves out like a convection vape.

 

[OF]

this is exactly what i measured in my (convection) vape.

also, there is a lot of radiant heat from the walls of the heater directed into the vial by the surrounding heat shield, so heat soaking the herb takes about 60 seconds.

I'd forgotten about this unit. IIRC it's true (and obvious) convection for the most part, like say the ESV is? That is you sense with a T/C the heater temperature and hold it to some controlled value? Any idea in degrees F what that temperature is? If it's really using a lot of Radiation (IR) to transfer heat through the glass (entirely possible, that's the only mode for Bender after all.....which has an incandescent heater) it must be quite a bit warmer than 400F? IR is just not a realistic heating mode unless the temperature difference is quite large and the distances small?

TIA. FWIW I like K types T/Cs as well, as long as they're appropriate to the job of course. Simple, proven technique

I've been thinking a lot about this lately. I think it comes down to us using a thermometer that was designed to be used in direct contact with the source being measured, and not an air flow. It reads fine on surfaces and conduction ovens. I don't think it has anything to do with the theory of the probes wicking away heat and distorting the readings...if that were true this design would be faulty in all applications and not just this one. But if that is happening, maybe we can quantify and account for it.

I get it (I think), that logic is OK for steady states (no heat flow, equilibrium) perhaps but in real world situations like this heat conduction up the leads is a known issue. If you stuck a piece of copper wire in the load it would have the same effects. The wire would get hot but not as hot as the herb, which would not be as hot as the cup. And it would draw heat away at a predictable rate that didn't get removed before it was inserted.

Poor contact with the heat source and heat loss through the leads are known issues with this technology. Notice how how our learned Brother HD suggests a different shroud or thicker leads could be a factor? That's cuz he's 'been there and seen that' I suspect.

Like I said before, a standard test is to try the same measurement with a probe of much smaller cross section (heat loss), if the reading differ you have an instrumentation problem and neither reading is 'right'.

Firm thermal contact usually eliminates this error in cases where the T/C is bolted or otherwise held firmly to the source. "Contact Probes" work well 'in their element' which is where heat transfer into the T/C is fast and easy compared to loss up the leads so the T/C reflects an accurate temperature.

I get it that folks want their favorite vapes to be convection but the reality is that conduction can produce vapor with much lower source temperatures (like 400F) while practical convection takes much higher source temperatures (like 1200C) to heat the air enough so it can contribute enough heat to be useful and still be over 400F. Convection mean temperatures that would cause combustion in a 'hybrid' potentially, should convection stop (like between hits) and conduction take over? Radiation takes even higher temperature differences to transfer enough energy to overcome losses and make vapor.

Lots of good reference stuff on this sort of thing, Omega Engineering is considered a top source.

okay, sorry ... different probe type? thicker or different shroud? thicker leads?

i use a BBQ thermometer for my real world readings, which i take apart to get to the probe element ... it has a small glass covered thermocouple, with thin leads - about 30awg

And lastly I'd like to point to PIU and their teardown of the new Air:

The Arizer Air was widely believed to be a convection / conduction hybrid vape but after fully taking apart the upper chamber and heater we can safely conclude the Air and Air 2 and most likely the Solo and Solo 2 are purely conduction vapes without any convection heating. Conduction is known for providing much better battery life than convection or even hybrid heating so the Arizer portable’s unusually long run time per charge makes a lot of sense.
http://blog.puffitup.com/2017/11/arizer-air-2-teardown-and-disassembly/

Just looking at it it doesn't seem likely. Look at how big the ports are and how thin the metal is the air must contact and be heated by as it rushes past. Only a tiny fraction of the air makes contact, then only for an instant and with metal not hot enough to heat it enough to be useful?

I'll hold that it can't be convection for a number of reasons and there is no such thing as a 'conduction/convection hybrid vape' no matter how much we wish? Physics is against it.

OF