Electronic Anti Rust Devices?

[Fishcop]

I regularly see advertisements for small electronic devices that are installed into cars to prevent rust. The theory is that a small negative (or positive?) charge is is permanently emmitted through the chassis and metal parts of the car which stops the rust from generating.

I've spoke to a few mates that are hard-core beach fishermen (we've got miles of beach designated as highway for 4x4 cars ) and they swear by the devices. But I've noted that their trucks are quite modern and galvansied, so I don't think it's a fair comparison with older cars.

Anyone using this kind of device? Anyone have some opinions? Is it voodoo?

Cheers

[Spede]

They seem to be really popular in Hawaii. I'm not sure if they really work or not but it really didn't help my aunt's 1995 Caravan there though.

[Charles Lee]

Its not Voodo, its call Cathodic Protection Engineering. The basic principle is simple, a metal dissolution is reduced through the application of a cathodic current. Cathodic protection work best to coated structures, with the coating providing the primary form of corrosion protection. Search web under CP..

[Lyle Detwiller]

I have a friend who lives in Rochester, NY (aka "Salt City") who has used them on two Ford Taurus cars that he previously owned and his current car, a Toyota Lexus. He is totally sold on them.

[tsuter]

I wear magnets in my shoes.....

[cstreit]

Tehnology like this has been used for a long time on ships. A small electric current is passed through the sacrificial devices on the underside of the ship...

[island911]

I thought about this once, but in terms of positive or negative ground (the Brit's had some cars with pos-ground) . . .which is better, for keeping the metal happy? That is, your battery is a reservoir of electrons . ..but which lead (to be grounded) will provide the easiest flow sacrificial electrons?


But then I thought, eh, I'll just buy an SC.


Ships wear "zincs" (big chuncks of zinc) which will provide sacrificial electrons to the steel.

My latest concern, however, has been that for the fan, and other magnesium parts. Those parts are like the zincs on those ships (electrolyticaly speaking).

[cab83_750]

The book I puchased titled "How to paint your car" talks about this item. I just bought a 74 (I think is not galvanized) will be wearing one of these units soon.

[charlesbahn]

It works well, if your car is submerged in salt water.

[SC-targa]

As charlesbahn said, I can't imagine it does anything unless the car is submerged. You need an electrolyte for the charge to pass through and you can't pinpoint it on a dry car. I've used sacrificial anodes (magnesium) to protect aluminum process tanks before with good results, but they were submerged.

Regards,

Jerry Kroeger

[wholberg]

Years ago I saw kits sold with a 3-5 lb zinc block that bolted to the inside of the body and was wired accordingly. The caveat to using them is that every body panel needs to be electrically continuous, or a piece of zinc needs to be on every panel. I saw one on an old truck years ago and the owner had actually spot welded connections between every body panel. In another application I saw the owner had connected every body panel with 10 ga. wire.

The use of a sacrificial zinc anode is not new, and it is a lot better than nothing on a non-galvanized car. I don't think it will substitute for modern rust protection, but in the Northeast, it will keep you from haveing to replace a non-galvanized body every 2-3 years.

Here is a commercial site I pulled up on Google that sells the zinc anode kits.

http://www.ruststoponline.com/ruststop-kit.html

[Fishcop]

Thanks guys.

I'm well versed on sacrificial anodes on boats, and as you rightly point out, that occurs in a conductive bath (seawater).

I just didn't understand how a current being passed through the car helped prevent rust. I guess anything that helps even slightly is better than nothing. I was hoping someone might have a couple of cars to compare - one with and one without?