I am being picky here, since for me
and my use the Grasshopper sets a
very high bar in actual vaporizing. It also has real drawbacks - apparently durability (though I got 2 years), hot vapor, rapidly heating mouthpiece, not very social.
(Oh, and when I talked of overshooting, I meant getting a bigger hit than I had intended, so being more baked than I wanted. Even though I use it most evenings, I operate on minimal tolerance and don't notice a difference after a few weeks abstinence. If I overuse and start to gain a tolerance, I lose the quality of the effects.)
I had to send it back in for recalibration
I'm afraid I did, and Marc says it was all functioning to spec, and I think it is. He tightened the friction zones too, though I was always getting good vacuum. I realize that I had been drawing faster than it can manage (though well within its buzz warning), but I expected it to manage more power given what the GH does with it's small battery (admittedly specially formulated for current, but my 18650s are to some extent - 25Rs).
But now I don't regret it I consider it my best vape. [...]
Each level is more like a temp range you navigate within with your draw speed.[...]
I don't know why you think tc convection efficiency isn't related too packing its all about the restriction and drawspeed ratio for a given temp. [...] I think [the GH] uses also some conduction?
It is a good vape in many ways, just lower than my probably too-high expectations for actual vapor production. Your 'navigate within your draw speed' gives me more confidence mine's working as designed, and it just has very incomplete temperature control. It's quite possible to heat air faster than it does, and if it can't manage it would be much better if it could give you feedback earlier, since it doesn't buzz until I'm fairly sucking a breeze through it. I suspect it must be just controlled to a fixed heating element temperature, rather than to an air temperature or something closer to that.
It would be possible to measure the air temp as it enters the chamber and control the heating element to that, but I think that would require a bigger unit, to avoid radiation heating the probe. More likely they all measure the temperature of the heating element (by resistance) and control that, but if you also measure current you could use that to compensate for faster or slower drawing to get some closer approximation to an air temperature control. My guess is perhaps that's what GH do, and/or do better. But I am guessing.
I've had a few conduction oven vapes but my only convection experience is the GrassHopper, which is sold as, and I believe is, pure convection. The heating element is so close that there must be some radiation and a little conduction but there is a heater in the air path in line with the bare thin walled tube about 20mm long x 8-10mm diameter that the weed is in. The air heats the walls of the tube and not vice-versa.
My ABV was even no matter how loose I packed, and the heat was, while not decoupled from air speed, at least closer, even as I drew at higher speeds. It was more constricted, so there was a limit on speed there, but I'm comparing the speed my lungs filled.
I'll be experimenting more with packing, or not. When I do a light fluffy barely-full pack I don't really see worse unevenness. It is a decent vape, but ironically I think it excels where the Grasshopper is weak and vice versa. I'd hoped for the best of each rolled into one, which ought to be very possible.
