|MadSci Network: Engineering|
While I have no direct experience with one of these systems I can comment on some of the claims and explanations offered by the companies that make and sell them. First, as Iím sure you know, rusting is a very complex process involving several different iron oxide and hydroxide compounds formed in a variety of ways under a variety of conditions. These reactions do all however involve the loss of electrons from the iron as it is oxidized. What these systems all try to do is make a source of electrons available in excess of those from the Iron alone. They claim to do this by causing the metallic parts of the car body to become the negative plate of a charged capacitor. This capacitor is then charged periodically as the negative charge drains away to the air and ground around the car. Because of the physics involved two things should be noted. First, based on the pictures I saw, only a fairly small capacitance is produced, which mean only a very small charge is stored at any given time. This is a good thing since you really donít want a large charge on a plate the size of a car body for safety reasons. Second, as at least one site correctly reports, this results in a very uneven distribution of this small amount of charge over the body of the car with a concentration of electrons at the sharper edges. At least one explanation offered also gets into some strange supposed alternating layers of opposite charges somehow progressing out through the surroundings that is almost certainly incorrect. As it adds nothing of any real importance to the argument physically or chemically I believe you can safely ignore it in trying to understand whatís going on. Given the nature of the chemistry involved all this would appear to only slow the rate of rusting not stop or certainly not reverse it to any real degree. I can see no good physical or chemical reason to discount their claim to slow rusting. In fact a careful look at the literature on a couple of sites reveals they actually claim no more than this. Because of the large number of variables involved however I know of no way to tell other than by experiment how much the rate of rusting might be slowed for a particular application. A person would already have to have a pretty good idea how quickly their vehicle rusted and in exactly what spots, or better have two ďidenticalí cars each driven and washed etc. the same way over a season or two to tell if the one with or without had noticeably different results. Some of the customer testimonials out there claim to have done some comparisons possibly like this with favorable results in industrial applications. Asked another way perhaps, ďGiven the cost of these things how does their price compare to keeping the car washed?Ē or maybe better, ďDo they give significant improvement above that already achieved by regular washing?Ē I didnít see enough data out there to really say. So in short, yes itís possible these devices work to some degree as claimed. Itís just hard to tell how well.
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