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Comment Doubt that Static is Caused By Much by Friction (Score 1) 86

When you think of things that make static, cling wrap, the belt of a Van de Graaff generator both seem to violate the friction idea. We have contact and surface area.

At a job, I pulled fiberglass parts from molds, a situation where you often have very little friction, but a whole lot of surface area, and dielectric materials like glass rods, polyester and epoxy resin. The parts wouldn't come out of the waxed and PVA'ed molds if there was a lot of friction.

When I pulled the parts from the molds, I converted the mechanical energy into electrostatic energy. The problem is: if an electrostatic potential existed in the parts to begin with, separating the plates should diminish it, because if you squish a capacitor the charge is supposed to increase. So, in inverse must be true, right?

So maybe this happens. Let's assume that the charge on the part and mold are neutral, that there is no potential difference or electrostatic field. When I was pull the part from the mold, I apply work that separate plates on a capacitor, with very little static charge, but I am guessing that it does create a small amount of negative potential, which is multiplied as I peel the two surfaces. Perhaps also, some current may flow along the sheet I am pulling through the dielectric. Perhaps those polarizing properties of it being a dielectric allow some current flow, just as capacitors leak

The part and the mold are connected at one end, and in the state of separating at another. I wish I could measure the static field just as the part comes from the mold.

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