ผมเล็งเทียนที่ใช้ทำน้ำมนต์ครับพี่ยุทธ ตอนลงอาคมไม่รู้ว่าจะไปที่ไหนดี 
เดี๋ยวลงให้ครับ แต่เวลาลง ต้องมานั่งล้อมวงกันด้วยนะครับ
Pitch is the black residue when heating pine rosin (=colophonium)
or from pine tar distillation.
The distinction between rosin and pitch was often not precise.
I doubt that there is any production of pitch today, because
beer kegs are not made from wood any more.
The black residue from coal tar formerly, today from crude oil
distillation is named bitumen.
It is used for streets, roofing and so on, there are different
qualities with respect to softening temerature.
Which grade of bitumen was used to fill transformers or capacitors,
I dont know. I would not do it, because it is a messy work,
and because it might come out on warming of the transformer.
All other drawbacks mentioned above are wrong, there never was
a kind of "purification" of bitumen with respect to acid or similar.
The only processing is to heat the vacuum residue of certain crudes
to 300°C for up to 3 days, while air bubbles percolate the hot bitumen.
This very brute treatment removes the last traces of volatiles
and oxidizes/hardenes the bitumen. (The acid content will rise!)
The degree of this treatment, and sometimes some natural asphalt
(e.g. from trinidad) blended to it, makes the bitumen "grades".
Wax:
Very problematic word! There is bees wax, some dozen sorts of
earth waxes, paraffin wax, and a hand full of synthetical waxes
(ethylene with some acrylic acid polymerized).
I guess here paraffin wax was meant. Again all ideas about
grades of different purity are wrong. The kind of process to isolate
it in petroleum refinerys makes it pure anyway.
Depending on the origin of the crude, the paraffin wax can be a
little bit softer or harder, that is all.
Concerning its use as a isolator, the wax from any (exept beeswax)
candle is o.k.
Due to a tendency to have crackles within the wax on solidifying,
wax is not as good as mineral oil as a high voltage isolator.
