re: Making oil from plastic (experiment)

He basically did what refineries do

I do. Most do.

He took used objects made of plastic and some car tire and heated, then cooled.
Heated, vaporized, cooled, some oily goo reflecting the objects.
Goo Burns.

Another poster suggested putting the goo through another round to get a lighter fuel. A real operation would plan for getting out the different distillates and selling or using them to make more objects.

I'm glad he wasn't killed by the pressure gauge. Others opine: "glad I'm not near him," and "he's going to gamble and lose life or limb".
Others, practical, point out how different commercial trial process is from this experiment.
Certainly a bangup beginning.
If you do this at home stay focused. And maybe use super glue at your pressure gauge.

If you missed parts, copy and paste those and ask questions.
Obviously some posters know this topic cold.
I took chemistry 60 years ago.
The op explained his doings well.
Peace. Out.