i thought i heard somewhere that it causes the dmt to turn to dmt n-oxide is this true?

It takes quite a while for oxidation to take place.

The fan should suck the naphtha, not blow air into the naphtha, otherwise you'll get air dust in your end product.

???

The air it pulls is the air it pushes out... so unless your fan is old and dirty, either way will work. Oh, unless you have a magic dust-fabricating fan.

But there is an advantage to pushing the air over the naptha - you should already be doing this near a window, and pushing it will allow you to put the evap dish as close to the window as possible and assure that the fumes end up outdoors, instead of indoors. Drawing air across the naptha and into your home sort of defeats the purpose of a window!

Oh and to answer your original question, the fan will speed up the evaporation immensely. However a MUCH better method is to freeze prepitate the spice. That way you forego any additives that might evap onto your precious crystals, and it also allows you to reuse your naptha, saving money AND the environment (how often is being green(er) cheaper?). It is also a much faster method than evapping.

HERE: WIKI - freeze precipitation

JBArk

Evaporating is very usefull when you get too much naphta for the amount of dissolved DMT... which always happens when you try to exhaust your bark from its precious spice.
Blowing air above naphta is no problem for the DMT in it. It can even be accelerated if place the naphta inside a jar itself in hot water (but not boiling). Warning, it may evapaorate too fast that way !
So let's say that you have 100 ml of naphta but nothing crystalize in the freezer. You reduce it to 20 ml, your naphta will be pretty yellow, but freeze precip will works.
Suggestion for the fan : an old processor fan or any fan from a computer plugged on a 12V+ supply works well.

Fact: you live in the Earth, air is full of shit.

You can blow air into/over the naphtha to make the naphtha vapors mix faster with the air and accelerate evaporation. That way dust from the air can (and will) end up in your product, since you are pointing the airflow against it.

You can also place the fan so it sucks air from the naphtha. It creates a lower pressure that accelerates evaporation and also vents vapors away. Since airflow is in the opposite direction to the naphtha, no dirt from the air will (easily) end in your product.

I don't know which method is faster, but the second one is certainly cleaner.

I've always used a computer fan rig for evapping to a lower volume for freeze precip or for evapping solvent traces. As long as you live in a relatively clean environment, you shouldn't have to worry about blowing dirt or dust into your xtals. Now, if you live in a complete pig sty or use a massive, dirty box fan, then sure, I'd imagine dust could be a problem.

Blowing air out of your evap dish is significantly less efficient than blowing air onto your solvent. Honestly, if you're really that concerned with dust or living in a nasty environment, put a stocking over your evap dish and then set a fan to blow on it. That will be cleaner than blowing your potentially dirty air on it and faster than trying to use the fan as an exhaust setup.

peace
SB

????

Sorry man, not trying to start anything here, but the air that flows over the naptha and into the fan IS THE SAME AIR that comes out of the fan. You don't suck air "FROM THE NAPTHA", because naptha doesn't contain air... we are sucking air over the naptha, which is the same air you would be blowing OVER the naptha if you turned the fan around. What you are refering to is not the direction of the airflow, but its angle and proximity. If you blow Or suck air OVER the dish so that no direct pull or push is experienced, THEN you create a low pressure area and pull (the same, again) air across the naptha.

Point the fan up when blowing across, or down or straight when drawing air, and you achieve this effect. BUT - it will take longer and ultimately, given that it is the same air in the same room, you will end up with roughly the same amount of dust in your final product...

But it is faster to have direct air flow, sucking or blowing, over the liquid being evapped. All things being equal, though, the faster the evap with this method, the more chance of dust. But like snozz said, unless you live in a pig pen...

JBArk

It takes some serious time under a high fan to create a good amount of n-oxide. Unless you've got it blowing on pure crystals for 8-10hrs I wouldn't worry about it. Fans are perfect for reducing your np extract prior to freeze precip.

is it normal that naphta boiling point is more than 150°C or near it? mine started to boil when termometer reach this temperature..

In some countries "naphta" means something very different from what is usually meant on this forum. It could even mean crude oil.

yup it seems to be kerosene or diesel,so swim is searcing a way to get it out now.. -.-

Here Where I live, Naphta (Or Napht as we call it) can mean kerosene or crude oil (But the correct term for the latter is Raw Napht).

There are two flavors, light naptha and heavy naptha depending on the average length of the mixed hydrocarbon molcules. Light should boil below 90C and heavy under 200C.