Anyone try adding thermometers to log vapes?

[iScrtAznMan]

Just curious if anyone else has done or thought of doing this? I feel like it wouldn't be too hard to add a temp probe to the basket screens to get temps of outcoming vapor to add another variable to manipulate. I've been looking at thermocouples used for ovens, but those probably have too much mass to heat up quickly enough. Glass thermistors look pretty promising though. Just need to custom build or poke a hole in a stem. Probably would be easy to do on a stainless stem or if there's a safe enough wire to run on the inside of the stem.

 

[Philabrookla]

I think your best bet is going to be pointing an IR thermometer at the basket, it should penetrate the clear tube. Maybe brace it on your rig like a banger thermometer.

 

[Buildozer]

@Stu and I have tested a bunch of different vapes with thermal probes, and I can't remember for sure, but I think he also did a log, there might be temperature graphs around here somewhere.. I think we would measure the incoming air though, and also had a probe in the load, I don't think we ever measured the vapor, but I think it would be interesting to do that. He has an lab glass adapter that works great for these tests, I don't have a picture, but maybe he can post one. It was set up for tests though, not permanent use.. You can also rig up a claisen adapter too, but the adapter Stu has is perfect for these tests IMO.

 

[EverythingsHazy]

I think your best bet is going to be pointing an IR thermometer at the basket, it should penetrate the clear tube. Maybe brace it on your rig like a banger thermometer.

Unfortunately, IR thermometers don't penetrate glass. They read the surface temperature.

Just curious if anyone else has done or thought of doing this? I feel like it wouldn't be too hard to add a temp probe to the basket screens to get temps of outcoming vapor to add another variable to manipulate. I've been looking at thermocouples used for ovens, but those probably have too much mass to heat up quickly enough. Glass thermistors look pretty promising though. Just need to custom build or poke a hole in a stem. Probably would be easy to do on a stainless stem or if there's a safe enough wire to run on the inside of the stem.

@Stu and I have tested a bunch of different vapes with thermal probes, and I can't remember for sure, but I think he also did a log, there might be temperature graphs around here somewhere.. I think we would measure the incoming air though, and also had a probe in the load, I don't think we ever measured the vapor, but I think it would be interesting to do that. He has an lab glass adapter that works great for these tests, I don't have a picture, but maybe he can post one. It was set up for tests though, not permanent use.. You can also rig up a claisen adapter too, but the adapter Stu has is perfect for these tests IMO.

I'd love to stick a probe in a Nano gong. and see how hot the actual bud gets, vs the heating element, because even if the heating element is 390F, the air is certainly cooler, to some degree.

The same goes for the Volcano. Is the digital temp, the temp of the heater, or the temperature to which the bud is heated?

It's just somewhat difficult to get a probe into a Nano gong. The volcano would be far easier to test. I wish there were little beads or discs that would change color, so you could justuse those as max temp indicators.

 

[iScrtAznMan]

Unfortunately, IR thermometers don't penetrate glass. They read the surface temperature.


I'd love to stick a probe in a Nano gong. and see how hot the actual bud gets, vs the heating element, because even if the heating element is 390F, the air is certainly cooler, to some degree.

The same goes for the Volcano. Is the digital temp, the temp of the heater, or the temperature to which the bud is heated?

It's just somewhat difficult to get a probe into a Nano gong. The volcano would be far easier to test. I wish there were little beads or discs that would change color, so you could justuse those as max temp indicators.

I feel like on the volcano, the heat source has more thermal mass and surface area so measuring the heater itself may not be as big of an issue unless the air is traveling too quickly and ends up leaving the heater before it heats up or loses energy in the chamber. Someone's probably calculated how long the air needs be in contact with the heater to fully heat soak when accounting for the fluid dynamics of the airpath vs flowrate.

I'm just tired of my log having a voltage drop when I draw to hard and there's got to be a better way to deal with this. I've noticed this drop on my cheap 'VVPS' from underdog, which I believe is based on a DC motor controller. This drop is most likely caused by the change in resistance through the ceramic heater due to a temperature drop and was curious if I'm still getting consistent temps if I don't baby my draw speed. I figure if I could get an accurate temperature probe into the air path, I could account for the V drop when taking a hit and supply more power to account for the temperature drop, either with a PID or through an Arduino. Or at the very least automate the effort of recovery without trying to manually adjust voltage.

@Stu and I have tested a bunch of different vapes with thermal probes, and I can't remember for sure, but I think he also did a log, there might be temperature graphs around here somewhere.. I think we would measure the incoming air though, and also had a probe in the load, I don't think we ever measured the vapor, but I think it would be interesting to do that. He has an lab glass adapter that works great for these tests, I don't have a picture, but maybe he can post one. It was set up for tests though, not permanent use.. You can also rig up a claisen adapter too, but the adapter Stu has is perfect for these tests IMO.

Honestly, just getting the temp as it comes out of the heater is probably useful for my primary goal of improving consistency. Being able to track the vapor temp after could give insight into how much thermal mass is lost through vaporization or heat loss through the stem/basket material is mostly just a bonus for dicking around. The claisen adapter looks promising though.

 

[Buildozer]

I'd love to stick a probe in a Nano gong. and see how hot the actual bud gets, vs the heating element, because even if the heating element is 390F, the air is certainly cooler, to some degree.

The same goes for the Volcano. Is the digital temp, the temp of the heater, or the temperature to which the bud is heated?

It's just somewhat difficult to get a probe into a Nano gong. The volcano would be far easier to test. I wish there were little beads or discs that would change color, so you could justuse those as max temp indicators.

I don't remember if the Nano was ever tested like that, but with the adapter Stu has it would be easy enough.
I don't think we ever tried testing the Volcano.. it's hard to remember what vapes he hasn't tested yet, there have been a lot.
I'm sure the digital readout on the Volcano would be for the heater temperature, I don't see why it would be anything else.. the heater seems to have a lot of thermal mass though, so temps seem pretty consistent with it, like other vapes w/ a large mass heater.

Honestly, just getting the temp as it comes out of the heater is probably useful for my primary goal of improving consistency. Being able to track the vapor temp after could give insight into how much thermal mass is lost through vaporization or heat loss through the stem/basket material is mostly just a bonus for dicking around. The claisen adapter looks promising though.

Yeah the results are pretty enlightening, especially w/ a graphing thermometer w/ 2 probes, you can see how it acts during different types of draws, and see how it recovers, and how long it takes to heat up, etc.
The claisen works perfectly for these things.. the adapter Stu got is just a little nicer to use, but the same idea.

 

[badbee]

@iScrtAznMan , I've been playing around with these thermistors: https://www.digikey.com/en/products/detail/amphenol-advanced-sensors/TG310J34GBNR/5819137 and an Arduino. You could give these a try, a got the super tiny ones which will adjust to changes very rapidly. They are so small I broke out laughing when I saw them, I mean really really tiny, it's like handling a single strand of stranded wire.

They don't work for measuring the temp of a vapcap (it can't be done with a thermistor), but should work great in an airstream or near a heater coil (watch that max temp).

 

[EverythingsHazy]

I don't remember if the Nano was ever tested like that, but with the adapter Stu has it would be easy enough.
I don't think we ever tried testing the Volcano.. it's hard to remember what vapes he hasn't tested yet, there have been a lot.
I'm sure the digital readout on the Volcano would be for the heater temperature, I don't see why it would be anything else.. the heater seems to have a lot of thermal mass though, so temps seem pretty consistent with it, like other vapes w/ a large mass heater.

Yeah the results are pretty enlightening, especially w/ a graphing thermometer w/ 2 probes, you can see how it acts during different types of draws, and see how it recovers, and how long it takes to heat up, etc.
The claisen works perfectly for these things.. the adapter Stu got is just a little nicer to use, but the same idea.

That's awesome! If you guys ever test the Nano's "load temperature", please tag me! I'd love to know. Same for the Volcano.

I believe the volcano would probably have a somewhat steady air temperature, but I doubt that the bud actually reaches the digital readout temp. I'd like to hit 390F without going over, but for now, all I can go by is an IR reading of the heating elements.

 

[iScrtAznMan]

@iScrtAznMan , I've been playing around with these thermistors: https://www.digikey.com/en/products/detail/amphenol-advanced-sensors/TG310J34GBNR/5819137 and an Arduino. You could give these a try, a got the super tiny ones which will adjust to changes very rapidly. They are so small I broke out laughing when I saw them, I mean really really tiny, it's like handling a single strand of stranded wire.

They don't work for measuring the temp of a vapcap (it can't be done with a thermistor), but should work great in an airstream or near a heater coil (watch that max temp).

That looks promising, I'll probably get one of those to compare to the thermocouple I was thinking of trying from thermoworks. Probably won't be able to use the thermistor close to the heating element, but it's hard to argue with that price. https://www.thermoworks.com/PRB-K-36X

I was planning to get one of these from Adafruit https://www.adafruit.com/product/3263, and hook up a mosfet to a GPIO PWM output to control the power to the log. Using a RasPi I could log temp and power over wifi and monitor how the log does in real time.

 

[Buildozer]

@EverythingsHazy
I haven't seen Stu in a while because of the pandemic, but he might have graphs of those vapes already I really can't remember, that was all a while ago. I think there's a thread around here somewhere where he posted a lot of the graphs for the tests he did, not sure what it's called though.. Now that I think about it, I'm pretty sure the tests were all done measuring the incoming air and another probe measuring what's going on in the load.. I'm pretty sure none were reading the heater temperatures.. still it's good info. I don't know how the volcano test would've gone, so I'm not sure that one happened, but I have a foggy memory of trying something w/ that one

 

[EverythingsHazy]

@EverythingsHazy
Now that I think about it, I'm pretty sure the tests were all done measuring the incoming air and another probe measuring what's going on in the load.. I'm pretty sure none were reading the heater temperatures.. still it's good info.=

TBH, those reading are more important to me than the heater temperature. I think I may have seen that thread, a long time ago, but I'll have to go digging, for a refresher.

 

[Morty]

Vape Temp Profile Charts

Hey guys, I’ve been doing some deeper vape testing these days and it’s really helping my understanding of vapes and vaporizing in general. You may have seen some of my posts already with the heating profile graphs and this thread is a central place for this data. I’ll also post appropriate...

fuckcombustion.com

 

[Alexis]

Vape Temp Profile Charts

Hey guys, I’ve been doing some deeper vape testing these days and it’s really helping my understanding of vapes and vaporizing in general. You may have seen some of my posts already with the heating profile graphs and this thread is a central place for this data. I’ll also post appropriate...

fuckcombustion.com

Hey Morty, unlike me,, ust a really quick hello amd hope ypu're doing alright. Always pleases me to see your name crop up on the forum board so I cpuldn't resist a pure, simple quick hi and hope you are goodd mate.

Thant's all. Too wasterd on kava plus some Bluedream vapor hits right now lol! To aadd ANY sense lol. Take care mate.

 

[iScrtAznMan]

@Morty thanks for the link, definitely some good info in there and looks like I'm repeating a lot of their steps. Interesting to see what jojo did with the MAX31856. I have to see if I can get the same thermocouple he has for a faster response time. Surprised only the IH guy wired his own pid, but I guess if you already have pid controlled vapes, no point wasting effort on a vape that doesn't have it already.

I made a very basic thermocouple with my pi and confirmed the recovery issues on my log at lower voltages. Wonder if it's just my heater core dying. Noticed first 10-20s hit could get up to 210C, but if I took another within a minute it would be around 180. At higher voltages, 240 for initial heat soak hit and 205 for second hits. I'll look into plotting the data into pretty charts eventually, but still just trying to setup the pwm output.

https://imgur.com/a/FnHhvoR

I tried to setup a simple PWM mosfet to control my log, but I think the RPi gpio isn't applying enough voltage to the gate or I underestimated the Drain to Source resistance. I'll need to do more trouble shooting. The 25W it uses shouldn't be that hard to control.

I've been thinking of setting up finned stainless tubes inside an insulated stainless tube to form an air path with dual cartridge heaters (intake driven higher and output set to target temp) to create a forced air convection heater. Like a more compact personal volcano heater.

 

[iScrtAznMan]

I wanted to post an update on my PID setup. I'm pretty sure I killed the first mosfet. After ordering some new ones and wiring it up with some LEDs just to confirm it's working, everything looks fine. I'm guessing my first attempt, I didn't include a pulldown resistor which probably led to partial gate voltage and eventually burned it out. I've torn apart my log after an O-ring failed to see if there's any potential of inserting a thermocouple. The cartridge heater only appears to be a 1" by 1/8" heater. There seems to be plenty of room to wiggle a thermocouple wire next to the heater. Just need to order a higher quality sensor and think of a way to route it neatly. I'm think maybe a hole in the base or maybe a small hole in the side.

Depending how this goes, I may just create an open air Kanthal coil enclosed in some steel tubes from McMaster. I still don't understand how cartridge heaters can be so pricy and feel like a long enough open air Kanthal coil would work just as well, since most heaters are just Kanthal inside a MgO powder with a stainless case. Although I did see Omega and McMaster have some cartridge heaters that come with a thermocouple in the tip. I'm thinking a 10mm ID to be compatible with Dynavap tips and would allow a pretty beefy 6mm coil.

https://imgur.com/a/0PfYupk

 

[Hippie Dickie]

i started with a log vape - ohm's law to set current in a nichrome wire to reach 400F. i added a BBQ thermometer to see what was happening with the heater ... after some years i switched to a PWM design after getting a PWM module on eBay to see how that worked ... which led to using a MAX6675 (predecessor to the MAX31856) with 0.010" k-type thermocouple (1/4 second response) and Microchip 12F683 for the PID control algorithm implemented in machine code (i'm a software guy) ... a kind and generous reader of my thread (see signature) schooled me on how to read the MOSFET spec sheet and i got that issue sorted.

my circuit is very simple, 23 components total, and achieves +/- 1F stability regardless of volume of air flow through the oven tube. i use LiFePO4 batteries that can deliver 70 amps continuous if needed, so the heater is a beast ... heater is 12" of 1/8" wide nichrome80 ribbon wrapped around a glass tube. a vial holds herb that is inserted into the glass tube. air flow is only through borosilicate glass.

this design is now 10+ years old. i think it is currently the 5th iteration of the pcb and this latest one was sent to a fab shop to see if components could be installed by robot assembly - and this worked just fine. i just couldn't solder the components reliably enough by hand - problem solved.

 

[iScrtAznMan]

@Hippie Dickie, I think I remember seeing your thread in the other post or when I was lurking. Definitely thing you must have influenced me at least subconsciously. What did they school you on for the MOSFET? You heat the glass right? Any issues with cracking? Being a software guy myself, PWM is much easier to work with than manipulating analog inputs. Rather offload the complexity of control to something I can understand. I don't understand why pid control vapes aren't the norm yet or why they end up so expensive. I feel like I'm missing something that makes this unrealistic or no one has bothered to show how easy it is.

 

[Hippie Dickie]

What did they school you on for the MOSFET?

my MOSFET was getting wicked hot because i did not have enough gate voltage to drive the MOSFET into the milliOhm resistance of source to drain. i thought i was being clever by using the gate control to turn on the red LED also. but that locked the gate voltage at about 2.5v. i moved the LED to a switched ground location and selected a MOSFET with a very low Rds at 4.5v ... the MOSFET stays cool to the touch.

Any issues with cracking?

no cracking with borosilicate glassware - just doesn't expand with 450°F heat - can cycle from ambient temp to vape temp and back with no problem.

I don't understand why pid control vapes aren't the norm yet or why they end up so expensive.

i totally agree. PID is the only way to vape for me. i think the mind set is race to the bottom in price. if i can bring my design to market, it will not be cheap. nobody has got my feature set (yet) for any price.

 

[iScrtAznMan]

It's been a while since I've posted to this thread. I got a Volcano over black friday and have been enjoying that. I found in one of their marketing videos, they talk about the heatercart having a thermocouple built in. I highly suspect they have a simple pid controller built in as well.

The Omega thermocouples I ordered just came in, 5 CHAL-005-BW thermocouples which are unsheathed and extremely fine. I'm trying to figure out how to deal with grounding issues, since the MAX-31855 doesn't work very well with grounded TCs. Maybe I'll look into a custom insulation wrap? I've threaded the TC through the core but I think I have it offset to the side too much, or I missed the weld and it's measuring the outer sheath temp. I may instead just try to wrap a TC around the heater cart instead as it will be safer, or maybe get a second amplifier so that I have the air temp and heater temp for redundancy. If I knew how to weld, I'd probably just build a heater core that I could better integrate easily accessible probes.

In the future, I'll probably have to design a base to house the thermocouple circuit so that the wires don't just dangle. The 12" length of the TCs makes it hard to use the log normally. So much for an un-modded appearance. Maybe I'll ziptie it on the side and call it Cyberdog2020 and patch it later. Once I figure out how to get accurate temps I'll post some graphs. Currently the data I have is good for tracking trends but isn't actual vape temps.

 

[iScrtAznMan]

https://imgur.com/qcUGmPo

https://imgur.com/l4SLJ5W

So I gave up on the Omega thermocouple and switched back to the insulated thermocouple. It was touching the outer sheathe and measuring the temp of that instead. I have the insulated TC pressed against the cartridge so I can get accurate temps. I may get another thermocouple board and use the chal-005's to check the temp in the bowl since they have a much faster response and it's easier to prevent grounding. The graphs show how slow the response on a log is at around 8V (I upped to 10V but let it heat soak(around 24 23:15), nearly combusted, and dropped back to 8V). This could be explained by the probe being cooled by the air around it or the surface temp drooping quickly while the core of the cart maintains most of the mass. Also, the bowl is already warm so less energy is wasted. The lows are within 25C of eachother despite the 100C swings. Heat soaking could take a full 5+ minutes to reach a stable temp. It also looks like it has issues keeping up with the airflow (I blame that on using a volcano for 2 weeks)? The slow response could be that I've been using this for 3 years and the heater is giving out; but, I think it's just an issue with how much thermal mass the log has. A PID seems like an easy fix and these are pretty standard cartridge heaters that can take at least 50W if not closer to 200W but I'll probably only drive at the default 5-8W until I find a fail-safe for thermocouple failure.

 

[iScrtAznMan]

I think this is turning less into a discussion and more of a log of my attempts. I'll probably start a new thread in DIY. I already started writing this one so I'll give the last update on the PID. I probably won't update until I get new hardware because I managed to kill the RPi yesterday, but once the new boards come in I can post an update. A faster Pi or an Arduino should improve the polling rate and help increase the stability of the system. Can set timed intervals and get better I and D readings, although overshoot isn't that big of a deal and P reacts pretty quickly anyway.

Hopefully graphs show up right, tried to get them all together. This is from all the data I've collected testing. The beginning is oldest, so less tuning and less power. The last 25% is from a day or two ago. The major spikes are doing straight draws with no load (so maximum airflow).

https://imgur.com/a/rkrZOwe

I was trying to figure out why the T120 darlington pair works and the mosfet didn't and while troubleshooting I most likely sent 19V through the Pi. I was being careless and was sticking multimeter probes everywhere to check the gate voltage. I think the next step is to try with a better mosfet rated to 60v 30a, but I think more likely is my powersupply to the PI wasn't giving enough power or the mosfet was way out of spec. I'll post all the graphs I've gotten up until now. I've managed to get the system pretty stable, but even at 19v (which pulls close to 20W) I can still overwhelm the heater. At this point, the PID is only really useful for the P control to act as a limiter/thermostat when idle and pump full juice when hitting. Still the recovery is much better than before but I don't have full control over the hit without setting temp way above my actual target (250 gives me around 220 after temp drop, better than the sub 200 before).

I ordered a variable switching power supply rated for 60v 5a, but I may start going down the DIY route and build a custom dual zone core (1 for conditioning and 1 for smoothing). The idea of driving over 20W without a secured TC and no safety mechanism scares me a bit. While I only ever run it while I'm using it and shut it off after using it, for longer sessions and long term use, this isn't really ideal. I also need to setup a static discharge for the TC. If you look at some of the graphs the initial temp is stuck and after I ground the TC, it recovers. It shouldn't be hard to setup a simple check if the temp is static between iterations to quickly shutoff heat and ground the TC with a transistor driven by gpio to reset it.

 

[iScrtAznMan]

So I lied about continuing this thread. I learned more about how mosfets work and want to share incase anyone tries to repeat. I think I have a better understanding of why I was blowing them up. Anyone that wants to use mosfets for power delivery should watch this GreatScott video

on what mosfet drivers do and how much current is needed to prevent the mosfet from failing to properly do its job. This video also does a great job explaining parasitic capacitance and oscillation if a gate resistor is omitted:

. I underestimated the Pi Zero, as it can barely provide 3v at 50 mA of current and without a resistor to limit current to the gate to slow the switching speed and reduce the capacitive load to the pi, a lot of power was leaking and amplifying the issues. I just wanted to put this info as a caveat to anyone else looking into DIY pwm.

 

[tokenknifeguy]

Unfortunately, IR thermometers don't penetrate glass. They read the surface temperature.


I'd love to stick a probe in a Nano gong. and see how hot the actual bud gets, vs the heating element, because even if the heating element is 390F, the air is certainly cooler, to some degree.

The same goes for the Volcano. Is the digital temp, the temp of the heater, or the temperature to which the bud is heated?

It's just somewhat difficult to get a probe into a Nano gong. The volcano would be far easier to test. I wish there were little beads or discs that would change color, so you could justuse those as max temp indicators.

Seems to me like one could sacrifice a basket screen and poke a hole in the center, just a cunt hair smaller than the diameter of the temp probe. Then stick the probe through the hole and stick it enough through the screen to have it at the proper length to measure the temp of air at the bowl level. Also seems like one could even then pack the bowl up with weed while the probe in there and hit it all and see whats up. My only problem with log vapes is that the bowl is way too small. Wish log vapes and all vapes in general had a larger diameter bowl that what is currently the standard. I actually like the design of the firefly bowl, and wish that was the standard bowl size, but just a tad deeper.

 

[iScrtAznMan]

Seems to me like one could sacrifice a basket screen and poke a hole in the center, just a cunt hair smaller than the diameter of the temp probe. Then stick the probe through the hole and stick it enough through the screen to have it at the proper length to measure the temp of air at the bowl level. Also seems like one could even then pack the bowl up with weed while the probe in there and hit it all and see whats up. My only problem with log vapes is that the bowl is way too small. Wish log vapes and all vapes in general had a larger diameter bowl that what is currently the standard. I actually like the design of the firefly bowl, and wish that was the standard bowl size, but just a tad deeper.

If someone made an insulated stem, I feel like you could pack the whole stem and get a joint effect going. I wouldn't do it with a non temp controlled log or it might combust. Probably have to preheat the stem before loading. I forget which vape that has the skinny stems with a wire to pull out the pack, but I feel like that would be amazing.

 

[hunter548]

Hi all. I used a meat thermometer (the kind where you insert the probe into the meat) inserted into my Volcano Classic filling chamber (empty) and resting on the upper screen to measure actual air temperature reaching the weed.

Elapsed Time	5	5.5	6	6.5	7	7.5	8	8.5	9
Orange Light Out (time)	n/a	3:11	4:06	n/a	3:52	4:27	3:18	4:35	6:00
Orange Light Out (temp)	84	100	97	108	107	99	122	111	107
30sec	268	285	269	290	279	295	303	317	301
45sec	288	303	293	309	313	325	338	344	338
60sec	300	312	305	319	324	338	351	355	349
1:40 min:sec	315	332	325	338	345	356	371	369	365
2:00 min:sec	320	340	333	345	353	363	378	375	371
2:20 min:sec	316	336	341	354	363	372	386	382	379
3:00 min:sec	320	340	336	348	370	381	394	392	387
4:00 min:sec	316	349	349	361	367	374	386	404	398

It takes about 30-35 sec to fill a bag, so it looks to me that I need to run the air pump for at least 30 sec or more to get the weed exposed to temps 315 or above before filling a bag. The main conclusion is that at least my Volcano Classic needs to run for a period of time before installing a vape bag because the dial setting does not instantaneously produce and maintain a fixed temperature. Rather, the temperature builds up over a period of operation time.

Anyone have any other data to share? Verification of the temps shown on a Hybrid?