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rust prevention box


comanche13
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Interesting idea. Any sciency types on the forum that can tell us if it's a con or not? Boats use sacrificial cathodes(??) to prevent the props corroding but I don't think they're powered. I'd get one if I knew it worked. The testimonials are glowing but they could be totally faked! I checked some of the companies names and they seem real enough.

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This is something I've worked a lot with in the past. It a version of cathodic protection for vehicles. Cathodic protection is used extensively on metal piers and other metallic marine infrastructure, and underground petroleum pipelines and tanks. Basically it uses a rectifier (in vehicle applications a battery) to create low amperage DC current flow (milliamps) through the metallic structure to an anode bed buried in the ground or the sea. Anode beds, usually zinc compound rods, are cabled into the circuit and have less resistance to corrosion than the protected structure, thus they oxidize (rust) and deteriorate faster than the protected structure. They are "sacrificial lambs" and must be constantly replaced to keep the DC current flow flowing and continue the cathodic protection on the structure. I used to work at POL (Petroleum, Oil, & Lubricants) piers and tank farms in the Philippines and other places (Nam) and part of my job was maintaining the cathodic protection system for underground/undersea structures.

 

All this being said, I have no experience with vehicle cathodic protection systems, but these systems have been around for many many years and they work very well if maintained correctly. I don't see any reason why a well designed CP system could not work on a vehicle. 'Course I don't need one in 'Bama. :smart:

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I used to install the Rust Evader units many years ago. Total useless crap. I tried to talk people out of them, which pissed off the parts and sales guys.There was no sacrificial anode, with the rust prevention purported to come from a slight electrical charge generated by two boxes hooked to the inner front fenders. But the customers had the satisfaction of opening the hood and looking at a blinking light on the control box, confident that it was keeping their Hyundai Excels from disintegrating in the NY road salt.

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The physics work if you are immersed in something that can conduct electricity, like water (ships, piers) or the ground (pipelines). Vehicles, however, operate in air, which does not conduct electricity.

 

It could technically possibly be made to work with two grounding straps dragging along the ground, but no system I have seen does this. The boxes are designed to look nice and complicated to make one believe it does what is really being done by the paint job, galvanized sheet metal and e-coated or polyester covered undercarriage used on most modern cars.

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It's called cathodic protection, and everything I have read about it suggests that it works very well.

 

(That's "cathodic" protection, not "cathartic.")

 

Gee, I think I said that about six times above. :D

Which, "cathodic" or "cathodic"?

 

Don't tell me you're one of THOSE people who fail to appreciate bad puns?

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It is possible to make it work, by using electricity it probably aids in the efficency of one sacrificial anode to work for the whole vehicle. I am a metallurgist but I don't know any elctrical stuff, you would need someone that knows both to see if the electricity helps... Sacrificial anodes have been used in vehicles, what do you think galvanizing is. and we have all seen how galvanic cell corosion works, ever seen a steel pipe conected to a brass valve or fitting? The steel corodes very quickly if it is exposed to water or something and the fitting will just fall right off in perfect shape... Yeah, and I think some one also mentioned it is used on underground pipes, they use magnesium primarily for that...

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I worked at a bosy shop some yrs ago, and a late 70's ford came in with lil zinc anodes attatched everywhere on the vehicle, and suprisingly the rig had no visible rust on it. Mind you this truck was used by a waterman to haul crabs to the pickers. Just needed a reapiant and some dent repair. :eek:

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