I made some extensive tests last evening (but again not with DMT, but I think most is also applicable for DMT).
I discovered a few things.
E.g. I thought that a very good setup would be to use a TC heating plate (my magnetic stirrer hot plate), where one can sprinkle the substance over a wide surface and so it should instantly evaporate. I added a metal tube with a diameter a bit smaller than the heating plate and a glass funnel on top, to see the vapor production. I planned, on letting everything evaporate, and then inhale the content.
But boy, was I wrong. There was very little vapor production, but most substance repeatedly just got burnt. But, e.g. when I blew on the plate surface, a crazy vapor production was the result.
It really seems this thin vapor layer above the substance is the culprit. The air there is saturated with vapor and so no more substance can evaporate. And by itself, it only moves very slowly (only due to air convection induced by heat differences).
So the most important factor is probably to consistently get rid of this surface vapor layer, as it prevents any further evaporation, although the substance is way hot enough. And exactly if the substance is that hot and cannot evaporate, it will burn (experience based on my tests).
My hypothesis would be, that if the hot substance is not exposed to the air, it's not such a big problem. If it is exposed to the air and can evaporate, the substance surface layer will immediately cool down due to this. If it is exposed to the air, and cannot evaporate it will remain hot and react with the air oxygen...
So in this relation the "ceramic sponge" on the GVG is good, as it increases drastically the surface, and by drawing in constantly fresh air, you get a high vapor production in a short amount of time.
I also realized, that with the heat and dump method on the QQ, you can draw very fast, and still vapor production keeps up (it has a big thermal mass, as well as enough power). IMHO the reason is as stated above. Actually if you do not draw fast, the substance will burn. The problem is here a bit, that the evaporation surface is very small. So to compensate this, a lot of air has to pass by this surface. The problem here is, that you only have a certain amount of breathing volume. So this limits the maximum amount you can evaporate in one draw. And if you have to wait for the second draw (keep it in your lungs for some time), substance will get burnt...
I basically found two solutions for this:
If you need to take more substance than you can draw in one rip, then split the substance in the number of rips you need, and while you exhale from your previous rip, dump the material for the next rip (while the QQ remains the whole time on the set temp). Like that almost no substance gets burnt. As said, I have a rubber hose with an attached aluminum tube on my QQ mouthpiece. The rubber hose has a big hole in the side above the mouthpiece. Like that you can easily dump more substance,and then close the hole with a finger.
The other solution I came up with, is a bit more complex and not really portable. I basically made a piston device, where on the bottom you can stick through the QQ (without the mouthpiece). Then there's an air pump installed which blows air fast (adjustable) in a narrow stream into the cup (to blow away the surface vapor layer). By doing this you can get a really crazy vapor production with the QQ, and even with bigger amounts of substance, all substance gets evaporated pretty quickly. Then when the whole device is filled with the vapor, and all has evaporated, I push one side of the cylinder (the other side than the QQ) down. In this plate that gets pushed down (which I made of transparent acryl) is the aluminum tube installed (which also serves as a handle), and so the vapor gets pressed out through this tube.On the other side of the tube I have a rubber hose attached as flexible mouthpiece. The only problem with this version of this design is that I cannot push the piston completely down, as the QQ is in the way...I would probably have to have an indent there, with the size of the QQ. But as I just used what was lying around, I ended up with this version. So when I finished pushing down the piston, I basically still had to draw, to suck in the remaining vapor. But as this was only a small remaining volume, it wasn't a big deal.
This device is still a killer. But as said, everything else but portable (or practical in its current version)...
The reason why I made a piston device was, that I realized with my bong tube like setup, that if you have such a bigger container of vapor, and you just draw the air out of it, you will need several times the volume of air of this container, until most vapor is out of it, and still then, some is still lingering around. Whereas with a piston, you really only have to inhale this amount of air. By setting the initial piston position you can also adjust the container size to your breathing volume. But always remember that if you drew in all vapor you still have to be able to draw in clean air, as otherwise all the vapor in your mouth and windpipe is wasted.
Theoretically one could also use an inert gas in the piston, to constrain any further oxidation, e.g. like it is done with the famous 5-MeO-DMT piston device.
I think it could even work on the fly (so with a portable device). For as I experienced, if one blows a narrow pressure stream of air into the cup, the vapor production explodes. So maybe one could just have an air pump blowing into the cup, and then one draws directly, without any vapor storage container. But if this really works, I would have to test. And as mentioned, none of these tests were made with DMT, so it remains uncertain what it also applicable for DMT.
Quote:hopefully also with 5-MeO-DMT
Honestly IMHO 5-MeO-DMT is really not a problem. I can already vape it fine with only my MBT. Reasons? IMHO you only need to evaporate a small amount of substance (15mg max), that it has only a small recondensation potential, and is additionally pretty heat stable and hard to burn.
BTW:
I could imagine a device, similar to the GVG, but with cold air. E.g. If one would have a metal sponge in a form, so that one could directly put current through it, it would heat the metal sponge (used like a coil). Now you could just draw cold air through it, and it should work. You would basically get a conduction heated device, with a huge surface, and by constantly drawing air through it, the problematic vapor layer should be no concern (basically like with the GVG). But you would probably need quite a lot of power, as the air cools the sponge and the sponge probably hasn't much heat capacity (thermal mass).
I claim not that this is the truth. As this is just what got manifested into my mind at the current position in time on this physical plane. So please feel not offended by anything I say.