All right, for those who are interested, plastic production in PneumaticCraft is up and running. Observations:
(1) The refinery is very slow, even with the maximum of speed upgrades allowed for a tier 1 air pressure system (which I tested but don't use - it requires one alumentum every 20 seconds, the same as my 36LP boiler which generates 200 EU/t), but the rest of the production process is fast.
(2) You get four distillation fractions, and can process heavier into lighter fractions with the thermopneumatic processing plant. The lightest is named LPG and is used to make liquid plastic in the same machine. The second-lightest is named "gasoline" and can be used in a GT diesel generator to generate power. The heaviest ist named "Diesel", but actually can't be used in a Diesel Generator. This is confusing. Since the heavier fractions can be processed into lighter ones, you can get any combination of gasoline and LPG out of your oil, only at least 1/8 is LPG (the fractions aren't distributed equally, you get more from the middle ones). I suspect that PC oil and the BC oil I am using are identical in that regard.
(3) Heat generation is more efficient if you place a block of compressed iron between the vortex tube and the machine that uses the heat.
(4) You make plastic sheets with the plastic mixer. It's extremely easy. Pump your liquid plastic in and make sure the mixer stays cool enough since the liquid plastic is considered hot and heats up the mixer (either use a vortex tube or just wait until it cools naturally - the latter is slower, but needs no power). As opposed to what the in-game wiki says, you don't make colored plastic with the mixer. At least I haven't found out how. Instead, you make white plastic, and you can craft that into the colored version with a standard crafting recipe of 8x plastic +1x dye.
(5) One nice consequence of this new system is that you don't need the pressure chamber to make plastic, which means that you need never bother with the primitive mechanics of having to break open the chamber to put something in - you can craft the chamber interface and use the chamber properly right from the start.
(6) All this uses up a ton of compressed iron. OK, maybe I wasted some because I made more machines than necessary before I knew what I was about, but I was rather glad I put eight stacks of iron into the initial explosion that made my first batch of compressed iron. The most annoying thing, on the other hand, was making the speed upgrades. Ugh. Potion making. Nether warts. Wheat, milk and eggs for cake. Sugar. I had none of that when I started. Accidentally, I found there is a glass bottle recipe for the alloy smelter that you can use in the steam age.
All in all, a really nice way of making PneumaticCraft plastic, which I like much better than the flowers. They were cool, but collecting them was a pain and farming them extremely complicated. Now for figuring out how I get to the drones.... Meanwhile, more mining. I need platinum for the vacuum freezer...
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As for a different topic: I am researching my way through Automagy, in order to see if it provides a block that can drop items into the world (and do it with more precision than a dropper - too bad we don't have Botania's open crate), In spite of having researched everything from regular TC except the staves and the as-yet unreachable stuff in the lower part of the Eldritch tab, and in spite of having researched everything I can reach except the Hungry Hand Mirror of automagy, there are five items still locked and I don't know how to unlock them (buyables don't usually unlock stuff): the item with the chest icon below the "Enchanted Paper" research, the item going off the Thirsty Tank, the item with the ring icon below that group, and two buyables in the upper right corner of the automagy tab. Can anyone help me out?