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

[sofarsogood]

It's been a while since I vaped an RDA but I used to use them all the time. I mostly used contact coils and after a while I moved to slightly non-contact designs and for a long time I would have agreed totally with you. I'm finding that coil design can depend a lot on the atty used, maybe more so in tanks. One of the more challenging tanks I've worked with lately is the Ubertoot UTA2. Here are a couple of pics of the second to last coil I made for it and this is the first one that got me close to what I was looking for:

I've never built a coil that spaced or that wide before, but I was looking for more TH and was getting frustrated after a whole bunch of failed attempts. Air flow in this atty is through the hole under the coil and making the coil wide enough to get some of it out of direct air flow got me going in the right direction.

This setup has just as much flavor and vapor saturation as my previous best with a design that was much tighter spaced, and was short enough to mostly be covered by the air hole. That formula had been working for me with quite a few atties but it just didn't give me enough TH with this one. The atty is just too smooth a vape for my taste

I guess what I'm trying to say is there few hard and fast rules in this game and what works well for some or most atties might not work so well for all. So for what it's worth, keep experimenting and don't be afraid to get out of your comfort zone

I care about throat hit, texture, and a little bit about flavor. My experience so far is I get the best results by rewicking twice a week (after 25 ml) and rebuilding twice a month (after 100 ml). Even though my coils hardly gunk and the cotton is baraely tanned under the coil keeping things fresh seems to help. The way I draw also seems to matter. I do MTL and some times slowing the draw improves throat hit. I use an SV rda exclusively because there are few parts, no glass to break, they are short and they are cheap for stockpiling. Going back to the topic of the thread, I'm actively trying to reduce power and heat and daily ml's consumed just because, well, because why not?

 

[mikepetro]

OK, as promised I ran some tests using a thermocouple on a Merlin RDTA to compare measured coil temp to what Evolv says.

I threaded a .010" thermocouple through the airhole up into the chamber

I tucked just the end up underneath the center coil.

I hooked it up to a Temp Controller that accepts type-k thermocouples. This controller was checked against a Fluke 725 Process Calibrator that is traceable to the NIST, and is within calibration date expiration.

I set the DNA250 to 400F (the insulation of the therocouple is limited to 500f) and fired the mod while capturing the thermocouple and Evolv's Device Monitor at the same time.

Discovered a couple of things:

• The thermocouple data acquisition software limited me in that it only had a sample rate of 1 sec, where Evolv's DM is about 10 times as fast.
• The thermocouple had a lag as compared to Evolv's resistance derived measurements
• Nonetheless, the max temp measured by the thermocouple was about 390. Evolv claims +/- 10 degrees so that was within tolerance, barely.

At any rate, this proved to me that Evolv's DNA is accurate. This was questioned earlier in the thread.

My next test is to bury the thermocouple into the center of the wick to try and measure the temp the juice actually sees there.

 

[dwcraig1]

I'd like to see the air temp inside the drip tip of a good hit on a high wattage atty.

 

[mikepetro]

I'd like to see the air temp inside the drip tip of a good hit on a high wattage atty.

That sounds easy compared to what I am doing here. I will try it after I pull the thermocouple out of the coil. LOL, it was a pain to put in there, not moving it until I am done with it.

 

[Ryedan]

OK, as promised I ran some tests using a thermocouple on a Merlin RDTA to compare measured coil temp to what Evolv says.

I threaded a .010" thermocouple through the airhole up into the chamber

I tucked just the end up underneath the center coil.

Discovered a couple of things:

• The thermocouple data acquisition software limited me in that it only had a sample rate of 1 sec, where Evolv's DM is about 10 times as fast.
• The thermocouple had a lag as compared to Evolv's resistance derived measurements
• Nonetheless, the max temp measured by the thermocouple was about 390. Evolv claims +/- 10 degrees so that was within tolerance, barely.

At any rate, this proved to me that Evolv's DNA is accurate. This was questioned earlier in the thread.

My next test is to bury the thermocouple into the center of the wick to try and measure the temp the juice actually sees there.

Kudos Mike, great experiment and the resulting data is great to have

If there is one thing I would be really interested to know it is what the temperature is under one of the outer wraps in your set up. You've kinda set up almost exactly the build I'm vaping in my UTA2 right now . I fully realize it might well be a real hassle to move the thermocouple and if that's the case don't worry about it. Just thought I would ask, just in case.

Rock on

 

[zoiDman]

OK, as promised I ran some tests using a thermocouple on a Merlin RDTA to compare measured coil temp to what Evolv says.

I threaded a .010" thermocouple through the airhole up into the chamber

I tucked just the end up underneath the center coil.

I hooked it up to a Temp Controller that accepts type-k thermocouples. This controller was checked against a Fluke 725 Process Calibrator that is traceable to the NIST, and is within calibration date expiration.

I set the DNA250 to 400F (the insulation of the therocouple is limited to 500f) and fired the mod while capturing the thermocouple and Evolv's Device Monitor at the same time.

Discovered a couple of things:

• The thermocouple data acquisition software limited me in that it only had a sample rate of 1 sec, where Evolv's DM is about 10 times as fast.
• The thermocouple had a lag as compared to Evolv's resistance derived measurements
• Nonetheless, the max temp measured by the thermocouple was about 390. Evolv claims +/- 10 degrees so that was within tolerance, barely.

At any rate, this proved to me that Evolv's DNA is accurate. This was questioned earlier in the thread.

My next test is to bury the thermocouple into the center of the wick to try and measure the temp the juice actually sees there.

Good Job Mike.

Always Nice to see some Real World Numbers.

 

[jwbnyc]

You sir, are a mensch.

 

[awsum140]

Great work, Mike! Out of curiosity what kind of wire is the coil made of, Ni, Ti, SS or one of the "exotics"?

 

[Eskie]

OK, as promised I ran some tests using a thermocouple on a Merlin RDTA to compare measured coil temp to what Evolv says.

I threaded a .010" thermocouple through the airhole up into the chamber

I tucked just the end up underneath the center coil.

I hooked it up to a Temp Controller that accepts type-k thermocouples. This controller was checked against a Fluke 725 Process Calibrator that is traceable to the NIST, and is within calibration date expiration.

I set the DNA250 to 400F (the insulation of the therocouple is limited to 500f) and fired the mod while capturing the thermocouple and Evolv's Device Monitor at the same time.

Discovered a couple of things:

• The thermocouple data acquisition software limited me in that it only had a sample rate of 1 sec, where Evolv's DM is about 10 times as fast.
• The thermocouple had a lag as compared to Evolv's resistance derived measurements
• Nonetheless, the max temp measured by the thermocouple was about 390. Evolv claims +/- 10 degrees so that was within tolerance, barely.

At any rate, this proved to me that Evolv's DNA is accurate. This was questioned earlier in the thread.

My next test is to bury the thermocouple into the center of the wick to try and measure the temp the juice actually sees there.

That's a total thank you! What a great job, and incredibly helpful to know from an objective third party. It certainly settles my incessant posting about is the temperature really legit. I'm very happy to see it is.

 

[mikepetro]

Great work, Mike! Out of curiosity what kind of wire is the coil made of, Ni, Ti, SS or one of the "exotics"?

SS430, with a TCR curve from Steam-Engine, SS430 works well in Watts mode too.

 

[sofarsogood]

If the entire surface are of the sensor was in contact with the coil wire and not any cottonit might show a temp closer to what the mod displays. The temperature of the vapor is going to be dependent on the amount of air passing the coil and the sensation of warmth should partly depend a lot on how dense the vapor is. More density should feel warmer.

Are the legs cooler than the coils? If the legs are supposed to be the same temp may be attaching to one of those, away from the cotton, will give a truer reading?

 

[mikepetro]

If the entire surface are of the sensor was in contact with the coil wire and not any cottonit might show a temp closer to what the mod displays. The temperature of the vapor is going to be dependent on the amount of air passing the coil and the sensation of warmth should partly depend a lot on how dense the vapor is. More density should feel warmer.

Are the legs cooler than the coils? If the legs are supposed to be the same temp may be attaching to one of those, away from the cotton, will give a truer reading?

The challenge is that I dont know how to attach it to a leg and hold it in place once I put the tank on.

The lag makes sense though, the coil has to heat up first, then the mass of sensor will heat up.

I measured off the center coil in this series, about 6-7 tests, the results were very repeatable.

I plan to test it again off an end coil. My theory is the end coils are a little cooler.

 

[Ryedan]

The challenge is that I dont know how to attach it to a leg and hold it in place once I put the tank on.

The lag makes sense though, the coil has to heat up first, then the mass of sensor will heat up.

I measured off the center coil in this series, about 6-7 tests, the results were very repeatable.

I plan to test it again off an end coil. My theory is the end coils are a little cooler.

Mike, where do you buy these thin thermocouples?

 

[mikepetro]

So, to correlate this for folks running in straight watts mode without TC:

• SS 430 coil, 26 awg, a 5/6 wrap, 3mm diameter, 0.317 ohms, rayon wick
• Started out at 20w, and after 1sec dropped to 15 watts to maintain 400 degrees

So out of curiosity I set the mod to watts mode at 15 watts and chained vaped a few hits.

• First hit was 400 degrees
• Each successive chain vape got a little hotter at the same 15 watts. By the third hit I was getting 440.

Backs up the concept of TC, as TC would have reduced the wattage to keep it from going over 400.

 

[mikepetro]

Mike, where do you buy these thin thermocouples?

Thermocouple Elements, Fine Gage, Usheathed Thermocouple, Bare Thermocouple

Edit: Above link is for uninsulated, this is what I used
Insulated Thermocouples

 

[sofarsogood]

So, to correlate this for folks running in straight watts mode without TC:

• SS 430 coil, 26 awg, a 5/6 wrap, 3mm diameter, 0.317 ohms, rayon wick
• Started out at 20w, and after 1sec dropped to 15 watts to maintain 400 degrees

So out of curiosity I set the mod to watts mode at 15 watts and chained vaped a few hits.

• First hit was 400 degrees
• Each successive chain vape got a little hotter at the same 15 watts. By the third hit I was getting 440.

Backs up the concept of TC, as TC would have reduced the wattage to keep it from going over 400.


View attachment 650861

Run the TC test again with dry cotton for wicking. That will avoid the cooling effect of the liquid on the sensor so it should read closer to the actual temp of the wire.

 

[mikepetro]

Same 15 watts in watts mode:

• 1st hit was airflow control closed off to a minimal MTL setting
• 2nd hit was with airflow opened up (keep in mind that a second hit is normally hotter with all else being equal)

More airflow cooled the coil.

 

[mikepetro]

Run the TC test again with dry cotton for wicking. That will avoid the cooling effect of the liquid on the sensor so it should read closer to the actual temp of the wire.

But that doesnt prove anything to me in terms of "what is real life conditions while vaping" which is my goal here. I am satisfied that the TC of the board is accurate +/- 10 degrees.

 

[awsum140]

Thanks for the wire type, Mike. And I, of course, wonder what happens with different wire types. No, I'm not trying to get you to duplicate this test with other wires, one if more than enough. I know Evolv originally designed around Ni-200 so I'd guess that's pretty accurate. If we assume, that nasty word again, that the TCR curves are the only variable, which they would seem to be, then IF they are accurate the temperature sensing should remain accurate from wire type to wire type.

If the wire is consistent I would expect the temperature to be pretty much the same at the legs, outer wraps and inner wraps. If there are variances in the alloy of the wire that would cause temperature variances as well. There may be some variation caused by the cooling effects of air flow and liquid flow but I am guessing they would be relatively negligible. The point being that the maximum temperature SHOULD be limited by the board measuring the resistance.

I'm not too worried about the temperature of the vapor at the mouthpiece. I can sense when it's getting too hot and it has to be substantially lower than the coil temperature.

 

[Eskie]

Same 15 watts in watts mode:

• 1st hit was airflow control closed off to a minimal MTL setting
• 2nd hit was with airflow opened up (keep in mind that a second hit is normally hotter with all else being equal)

More airflow cooled the coil.

View attachment 650863

That's a little warmer than I would have expected from 15W. The role of airflow is obviously expected. The TC stuff really did make the point about real world usefulness. Of course I never expected great precision, but am impressed that it did come so close.