To begin with, we should say a few words about whether everyone should learn to prepare free vape juice on one’s own; and why do you need a self-emplacement when there are a lot of different ready-made liquids of different strengths and tastes in the market.

Self-preparation of liquids can pursue several purposes:
Reducing the cost of e-liquid brands purchasing;
Getiing cheap premium vape juice of high quality / purity;
Getting strength / properties / e-liquid flavors, which are not even in premium e-juice sale;
Stability of strength / properties / taste.

Self-mixes – more precisely, the experience and understanding of the salf-mixes allows you to prepare the optimal liquid for a specific device, or for a specific flavor: the more powerful the device is. There are rquired more fluid; non-sweet taste, the less glycerin in the mix.
So, a bit of theory:

There are 5 optional e-liquid ingredients of vape liquids:

Propylene glycol (PG);
Glycerol (GH);
Water (HP);
e-liquid nicotine;
The taste will largely determine the taste of the finished liquid, so it is important to first choose your own best e-liquid flavor concentrate.
Now consider what each of the components represents:
Propylene glycol (propaldiol) is a colorless viscous hygroscopic liquid with a sweetish taste.

Top vape flavors of liquids on pure PG are very “tough”: they give a stronger hit to the throat; better convey the flavor of the flavor, faster satisfied with the desire to vape. At the same time, the vapor is visually small. Liquids on glycerin on the contrary are more “soft”: the taste is weaker, or the percentage of flavor is required, the throat hit is minimal, they are hard to get high.

Distilled water. It is a good strongly polar solvent. Distilled water should be used for self-mix, as any other water usually contains dissolved substances (salts, gases).
Speaking about nicotine for self-mix, we mean exactly “synthetics”, nicotine from just three manufacturers: in Darmstadt, in Cincinnati and in Shanghai.