(continued)
Stem system
As illustrated in my previous size comparison post pictures, the stem system falls between the more common 14mm and 18mm standard glassware. The recessed stem also allows for some extra length compared to the stock stems of the competiton, even if not much.
18mm vapes tend to be the most free-flowing. So much that for instance RBT had to build resistance right into the device for the Milaana 2 and Splinter. We've also seen recommendations about putting a piece of rolling paper with fine poked holes on the Zion intake to increase vapor density without putting too much burden on the user.
If the vape doesn't create the resistance itself then you have to regulate the draw speed yourself, and it's apparently not intuitive nor easy at all for some users. We had the same issue with the Ascent back then: to get any meaningful kind of clouds you needed to sip so slowly, there definitely was a technique to acquire. So much that apart from my girl, none of my friends were able to get good hits with my Ascent.
Contrast that with the OG Solo where it was so easy to get good rips but in counter-part people kept complaining about its milkshake-like draw resistance. It's always a matter of balance.
The only way to please every-one would be to have a variable geometry air-intake. This was often proposed but rarely implemented. We will be getting it in the upcoming MistVape Touch 2 though, so have a look at this thread if you are interested.
The air-flow requirements are also much different when hitting the vape dry compared to using it through water. This has to be taken into account.
A downside of 18mm systems is that when the stem is short like in the Milaana, Timber and iHeat, you get a lot of hot air right into your throat and it can feel uncomfortable quite fast. For me, the Milaana stock stem is the bare minimum I can withstand and the iHeat is a tad too short.
While I prefer the flow of 18mm systems, I find 14mm ones to be much more forgiving on the throat given the exact same stem length. My MistVape Touch and Project Pure SF both use the same stem and feel more comfortable. But there are drawbacks too: 14mm systems invite you to micro-dose. I like using between 0.08g and 0.12g per bowl, with 18mm this makes a shallow puck whereas with 14mm this makes a deeper cylinder.
The net effect is that stirring is almost optional with that load size and 18mm, but you need to flip the load at least once with 14mm (you can see a clear color gradient from the bottom of the bowl to the top near the screen, regardless of how even the "heat front" is)
So where do we stand with the Nomad? I would say we get the best of both worlds. It's super free-flowing, surely too much for some users in fact, very easy on the lungs, almost no restriction. Vapor feels cooler than 18mm systems (the extra stem length does play a little here) but at the end of a session when you try to extract at higher temperatures you can still feel some dryness, but it's nowhere like the Milaana or iHeat.
The stem size is geared towards micro-doses but less than a 14mm system. I think if your load is close to 0.12g or more, then you will need to stir once per session. If your load is close to 0.08g or less then you won't have to stir at all.
I would like to see a longer stem offered as an option / accessory. It doesn't look like much but just a couple centimeters of extra length make for a very noticeable difference in cooling, especially with glass stems. In the Zion I only use the longest stem (the uncut glass blank one) which doesn't fit in the storage compartment (that one would the medium stem)
It would make the vape aspect-ratio / proportions a bit less appealing but as I said we got plenty of room before it starts looking out of place like a silly antenna. And again, with the stock stem your face ends up almost touching your hand when you use the vape, it can feel a bit awkward to some users I imagine, so the extra length wouldn't hurt either in that regard.
Screens system
I initially pronounced some reserve about the double-screens system, thinking it would be a chore compared to a single stem screen + fixed heater screen. But now I completely changed my mind. It's better this way!
In the Milaana for instance, it's true that usually nothing falls from your stem at first. But when you stir once mid-session (if you do) then you may have a few specks falling onto the heater screen. These are quite easy to remove by just blowing on it.
Here the heater screen would be way deeper inside the device where it's harder to see. Plus there are the o-rings above so when you put the vape upside down to remove the specks they could cling to the o-rings crevices.
With the double-screen, nothing falls down ever. It's always self-contained. For sure it adds a single extra step when loading and the same when unloading, but come on, we are not that lazy! After a session the screen cools down super fast. I just use my pinky to remove it (it's super close to the edge, you don't need any tool) then I can blow the load out or use anything to stir it out. I never touch the second screen, it always stays inside the stem.
When loading I do the "suck the load from my palm using the stem as a straw" technique, like with my other stem-based vapes. Then I just push the screen in. It compacts the load into a small puck, a technique I've been recommending with nearly all vapes (especially with conduction but surprisingly also with convection ones, as long as it's not too tight it definitely helps to get good vapor density)
I didn't do A/B comparisons with or without the second screen but I'm under the impression it really contributes to get an even roasting and lower the likeliness of getting any hot spots. The screen must spread the heat somehow and contributes a tiny amount of conduction.
Hot spots
Talking about hot spots, it's a question a lot of you have since it's the bane of full convection vapes usually. I agree with
@pakalolo when he says that they are mostly a function of temperature and draw speed (plus packing and grind size), if you extract slowly and gently then you can prevent them in most of these on-demand vapes.
That being said I disagree with him when he implies those are the only parameters. The heater geometry clearly has a big impact on the "heat imprint" on the load. We demonstrated that clearly in the Project and BULLI threads, then later on when Dave tweaked the MistVape Touch coil geometry based on this feedback.
We've seen very focused center hot spots when the coil had a central tight winding and could mitigate the issue when gearing towards pancake / stove designs for instance. We've also experienced designs that led to a clear offset crescent pattern on the load etc.
Moreover, the air intake geometry also plays a crucial role here, but its effects are much less intuitive to grasp. Air-flow dynamics and turbulence is such a complex subject, especially when you know that these systems can easily become chaotic.
With the Nomad, I haven't been able to spot any clear bad tendency so far. But I've experienced different patterns as there are many parameters. I've had a few occasions where the load was packed too tightly and it created some minor tunneling (you can see a dash of brown that seems to have sunken between plant bits) I had a few occasions where there was some unevenness that I could clearly attribute to bad grinding (i.e. a large bit of flat leaf material was facing out from the bowl and it shifted the air flow around it leading to some uneven concentration)
But otherwise, when I extract at my usual pace (i.e. dry, many hits, not big rips through water) the extraction is remarkably even. Better than in my Milaana, iHeat and MVT. Comparable to the Project Pure SF (but with 14mm systems the extraction seems to always be more even as the load has a smaller surface area anyways)
When I scorched the load (using the high-power heater with just a single hit) then I could see a pattern: it was a large circle slightly offset from the center. Say 95% of the load was scorched in a perfect filled circle fashion, but this circle was slightly offset and touching the border. The rest was green.
In all cases, I won't lie to you, there is always a very thin layer at the interface with the glass that ends up lighter in color. I think it's inevitable with a round stem system, there will always be more air flow in the center and less close to the walls. But in this case it's very minimal, no worries.
This thing, regardless of it’s diminutive size, is a BEAST!
Be careful, or you too may suffer the woes of the Nomad.
). On the other hand, if Dan can accomplish the same result with stainless, I’m sure it would broaden the appeal.