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Now that I have a still with an observation window I noticed that it only boils in a small number of spots. I'm hoping to create to create a more even boil. The inside of the still is polished stainless steel. I noticed that the areas that bubbled were directly over the heating elements or a couple other spots that had flaws. So as an experiment I gently sanded a small area of the still with 120 grit sandpaper. The area does not bubble during operation and is away from other areas that do. I didn't want to go too crazy with the grit as I still want it easy to clean. But if the 120 doesn't work I will try 80, then 40. With each grit I will do a different area and see how each one works. Once I find one that does a good job I will sand the entire bottom surface of the still. I may or may not do the sides.
Once I do a few runs I will report back.
Nucleation in boiling can occur in the bulk liquid if the pressure is reduced so that the liquid becomes superheated with respect to the pressure-dependent boiling point. More often, nucleation occurs on the heating surface, at nucleation sites. Typically, nucleation sites are tiny crevices where free gas-liquid surface is maintained or spots on the heating surface with lower wetting properties. Substantial superheating of a liquid can be achieved after the liquid is de-gassed and if the heating surfaces are clean, smooth and made of materials well wetted by the liquid.
Superheating is what I want to avoid. I want a nice even boil at consistent temps. With superheating you can get surge boiling which is uncontrolled and inconsistent. I'm hoping that also will help with separation of the factions. It may also help with increase the speed of production too though maybe not that much?