@VaporSipper, The only way I was able to achieve the small size with this design was to go unregulated. A module add-on, that adds a second battery + regulation, is possible for the future.
I also really liked the fully mechanical nature of unregulated.
I just meant a simple potentiometer on the voltage line to "regulate" the power going to the heater. Is that too far off the mechanical nature of the unit? Something you would adjust once, with a screwdriver, to your liking and leave it alone from then on. No electronics.
@GreenHopper,
It's a combination of many factors, current applied, air speed, starting air temp, geometry of airway, heater material..etc..
If your heater wattage is too low, you'll be removing heat faster than you can make it. To a point where you reach an equilibrium, somewhere in a low temperature range... too low.
If your wattage is too high, you are making more heat than you can remove, even with the hardest of inhales. Eventually the heater will overpower you and reach combustion temperatures. You need to feather the fire button on and off to control the heat.
A heater module that is just right, IMO, is one that reaches equilibrium at your desired inhale rate, at your desired temperature. This will be different for everyone, hence the need for different heaters.
Of course...with an unregulated heater.. you'll always have to bleed through into over or under powered territory as your battery voltage changes. So it's better to start overpowered, and settle into the sweet spot.
An XL version, with larger heater diameter, larger diameter glass stem..beefed up everything, would definitely be possible..and probably give some insane performance.. but it would definitely be more expensive. I would love to make it though, haha.
You would need a trimmer able to dissipate a lot of power. The one listed above can only do 0.75W for instance. So you would need something way larger with a proper heatsink.
With the heater resistance values that Dan hinted (between 0.5 and 0.6ohm) we'll be closer to 7-8A in practice on a fully charged cell.
If say the heater was 0.5ohm and you wanted to drop 0.1ohm with your trimmer, the current through the circuit would be 7A on a fully charged cell at 4.2V. Being in series the trimmer would have 7A through it. It would drop the voltage by only 0.7V but that's already close to 5W to dissipate.
It is possible but basically you would end up with two heaters. One heating your load and the other heating your hand and the vape, and basically just wasting energy. As @ZC said this is not the proper way to do.
14mm is totally cool with me. I have a milaana and supposedly a zion coming to meet my 18mm "needs". For 14mm, I have held off on the very intriguing tubo evic so as to better prepare ($) for this one.
@VaporSipper Regulation is more complicated than that though. Those little pot boxes can't handle 10A being run through them without other circuitry. If it could be that simple we'd see the ecig community using this kind of thing all the time.
I'm still firmly in the 18650 camp, because capacity can always be increased by carrying more batteries but the size can never be decreased if the battery standard is bigger. If a single 18650 isn't enough for a day, then I'll swap it. If I'm burning through many batteries a day I'm carrying around a stash/stir tools etc with me anyways so I don't see carrying more batteries as an issue.
That said, I'm totally into more options so I'm eager to see what results we see from the bigger units when you end up making them.
As for heater tuning, I prefer a hotter tuned heater. It's easy to lay off the button or feather it to get your desired temp if the heater is too hot to hold down the button, but if holding down the button doesn't get you enough heat, you're out of luck. So while a hotter tuned heater may take more finesse for lower temps, it also provides a much wider range of temps and is much more versatile. But again, more options are better, so I'm really excited to see all the differently tuned heater modules you come up with.
I'm not a fan of NiChr wire for our purposes. I recently got to do a true side-by-side test of NiChr/Kanthal/SS in some concentrate pens and the taste differences were quite pronounced. NiChr tasted bad, Kanthal tasted weird, and SS tasted pure after the first hit. The weakness in the test is that it was a single temp pen, so I can only assume that the temp used was higher than what we are doing with dry herbs, but everything else was identical except the wire composition. The NiChr might not taste bad at our lower temps. I am expecting to be able to compare SS and NiChr side-by-side for dry herb purposes within the next month and will let you know how it goes when I get it.
But all things considered equal, I will always choose SS and won't get excited about NiChr.
I tried some flat SS ribbon once but it was a pain to work with, way too much springiness. Apart from coils I wasn't able to make it hold any other form.
To answer @marduk, one advantage of NiChrome is that you can roll it tight without shorting. If Dan were to make the same heater geometry we saw out of SS, it would be really hard to prevent shorts.
But Dan already has some SS heaters options in his sleeve, don't worry!
I cannot fathom why a high resistance titanium wire would be preferred over a low resistance wire. A higher resistance wire requires more power from the battery and will undergo a greater voltage drop across the load compared to a lower resistance wire (which consequently requires more amperage to sustain power output).I don't know much/have no experience with concentrates/atomizers, but I researched the dr. dabber ghost and aurora vape pens yesterday by reading a couple of reviews about them so I'm an expert now
Seriously, I hope this makes sense to the experts out there (please feel free to correct any wrongs), as I didn't know any of this stuff yesterday. So maybe there's others out there as clueless as I was
According to the vape critic, "high resistance titanium wire, wrapped evenly around a high-quality wick" is one of the best/safest ways to go. Conversely, in the aurora review by the cannabist, they pointed out that one of the included atomizers was decidedly not the way to go, as the broken edges around their low-quality ceramic wicks* can cause silicosis which sounds quite unpleasant. The aurora also includes what appears to be the best of all atomizers, quartz rods. The consensus seems to be that ti is the best heating wire while quartz is best for wicking, with ss and the glass(?) fibers coming in as pretty acceptable alternatives.
I ordered a ghost because it came with two ti/fiber atomizers, but the quartz setup on the aurora does seem very nice. And of course another reason is again to save the duckets toward whatever's going on here.
According to "dr. dabber":
- Dual Quartz Rod with Quartz Dish: Suitable for lower viscosity oils
- Dual Ceramic Rod with Quartz Dish: Suitable for waxier oils
*But again with the warning regarding the dual-ceramic rod setup:
- Ceramic Halo Heater with Quart Dish: Suitable for higher viscosity oils
The "worst":
Here’s an extreme close-up of the ceramic wicks. "If you’re worried about silicosis, broken edges don’t inspire confidence." (Chris Thomas, The Cannabist)
Now for the "best":
"At the bottom of the chamber there are 2 quartz rods wrapped in a titanium wire coil, and honestly I think this style is the sexiest looking of them all." It’s [vape critic's] "favorite one to use":
Finally here's what I ended up with for now, two of these which seem to be "second best":
That opinion is factually incorrect. Some metals may react with some substances. Other materials are inert and have no interaction. Titanium is such an inert metal, it is so benign that it may be implanted inside the human body without issue. I have the same opinion as @stickstones that nichrome wire doesn't ever taste good in an oil vaporizer - its metallurgical composition makes it impossible to 'temperature control' based off a measured increase in resistance, its hard to control with fixed voltage output pens which is why most nichrome heating elements glow red hot in just a few seconds in standard 'wax pens'. Stainless steel are composed of alloys- various types indicated by the number following- and these alloys may be perfectly safe at lower temperatures, but at higher temperatures they may degrade. When used in a temperature controlled device there should be no concerns, but in an unregulated device it might be possible for the SS to be heated to a dangerous level.. Grades 1-4 of titanium degrade into titanium dioxide when overheated. TiO2 has in the past been recognized as safe, but recent study on nanoparticle inhalation is shining some focus on different ways that TiO2 can enter the human body and whether high levels of these nanoparticles can lead to cancer. the IARC has classed Ti)2 dust as a Group 2B carcinogen meaning it has not been proven to cause cancer, but "may be partially carcinogenic to humans" I for one and looking forward to further study about this topic: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3423755/ Luckily in the same way that SS can be temperature controlled and kept far below a level at which this worry would crop up, titanium (at least grades 1-4) can be temp controlled for safetys sake (and fantastic flavor too)I'm not into concentrates, but in the Divine Tribe thread they are raving about their ceramic donuts. AFAIK in these designs the material is only in contact with glazed ceramic and never touches the coils.
I wouldn't want my material touching metal. It's chemically active and likely to react one way or another, especially at high temperature.
That opinion is factually incorrect. Some metals may react with some substances. Other materials are inert and have no interaction.
The ceramic donuts are a great way to heat oils, but the same "run away" heating effect occurs (...) and as the remainder of the oil sits in contact with a heated surface, it undergoes thermal degradation.