chemistiller wrote:I know zinc is a hard metal but don't know much about its reactivity to the alcohols and ketones and everything produced in a run.
I know it would be an awkward inefficient use of all that heavy steel, because you could go much with thinner walls, but fence posts are everywhere people are always replacing them, and some of them are thick enough to look like reflux column to me.
Anyone see a flaw in my logic? do galvanized steel fence posts belong in the What not to Use category?
sorry, I just had to post something.
Zinc is NOT a hard metal. Also, Zinc is generally VERY reactive, particularly to salt, acids, AND bases. It even will oxidize in pure water (PH 7.0).
Zinc is used as a lead substitute in bullets due to its density and softness. It is a heavy metal, not as toxic as lead (not even close) but it is still a toxic metal. Zinc toxicity is well below the tasting point with chronic (ongoing) exposure. Also, like lead, Zinc can accumulate in the body.
Now, here is why people think Zinc is hard, non-corroding, and safe:
#1: People think Zinc is a hard metal because they usually only encounter it when it is plating something....which is usually harder than the zinc. Imagine coating a steel pipe with a .3mm layer of plastic, it would feel hard like steel, but it is just a soft substance that is so thin that it feels hard due to the substrate.
#2: Zinc corrodes, but like aluminum it is a self-protecting corrosion. A layer of oxidation forms over the zinc and as long as that layer of oxidation remains intact, the underlying metal is preserved. In a still you will run the risk of leaching the metal every time you stir a galvanized pot, or adjust a pipe fitting, or when the flow of alc is sufficient to erode the oxide.
#3: Zinc is not even safe for cold water pipes. Steel water pipe is only galvanized on the outside, another coating is put on the inside of the pipe. As a soft, heavy-metal it can be stupid toxic.
Please please please do not use the Zinc pipes. treat Zinc like it is lead.