# electronic rust protection

**URL:** <https://boards.straightdope.com/t/electronic-rust-protection/126421>\
**Category:** Factual Questions\
**Created:** [August 31, 2002, 7:36am UTC](https://boards.straightdope.com/t/electronic-rust-protection/126421 "2002-08-31T07:36:35Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![lotek40](https://avatars.discourse-cdn.com/v4/letter/l/e9a140/32.png) [@lotek40](https://boards.straightdope.com/u/lotek40)\
**Post date:** [August 31, 2002, 7:36am UTC](https://boards.straightdope.com/t/electronic-rust-protection/126421/1 "2002-08-31T07:36:35Z")

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does anyone know anything about electronic rust protection for autos? does it/can it work? i’m restoring an old landcruiser and need all the help i can get.

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**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\
**Post date:** [August 31, 2002, 11:54am UTC](https://boards.straightdope.com/t/electronic-rust-protection/126421/2 "2002-08-31T11:54:31Z")

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Boats use zincs to prolong life (It basically makes a battery where the zinc is what gets eaten up 1st.) I don’t really know if ERP works outside of a water environment but I see no reason why you couldn’t use external power instead of the electrochemical of the zinc method.

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**Author:** ![femtosecond](https://avatars.discourse-cdn.com/v4/letter/f/f08c70/32.png) [@femtosecond](https://boards.straightdope.com/u/femtosecond)\
**Post date:** [August 31, 2002, 12:58pm UTC](https://boards.straightdope.com/t/electronic-rust-protection/126421/3 "2002-08-31T12:58:42Z")

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I think this post from this thread [Magnesium Strip to prevent rust: Chemistry Experts Unite!](http://boards.straightdope.com/sdmb/showthread.php?threadid=106688) pretty much summarizes it:

> [@](#):
>
> _Originally posted by sailor_  
> **If the car is submerged entirely in water a sacrificial anode would help. On a car driven on the road it would be totally useless.**

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**Author:** ![matt](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@matt](https://boards.straightdope.com/u/matt)\
**Post date:** [August 31, 2002, 2:22pm UTC](https://boards.straightdope.com/t/electronic-rust-protection/126421/4 "2002-08-31T14:22:52Z")

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**k2dave** said: “but I see no reason why you couldn’t use external power instead of the electrochemical of the zinc method”

You are correct. It’s called “impressed current cathodic protection” and has some pros and cons compared with sacrificial anodes.

However, **sailor’s** quote above still stands - cathodic protection only works when the electrolyte is in contact both with the sacrificial anode and the piece of metal you are trying to protect. Zinc or magnesium strips (or impressed current anodes) will at best protect the steel about 1mm away, and only from corrosion by large droplets of water that touch both the steel and the strip.

Oh - and you know those “rust converters”, milky liquid that you paint onto rust, which turns it black? They don’t work either. (They turn the rust black, but they do not convert it into a suitable substrate for painting over, as claimed.)

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**Author:** ![lotek40](https://avatars.discourse-cdn.com/v4/letter/l/e9a140/32.png) [@lotek40](https://boards.straightdope.com/u/lotek40)\
**Post date:** [August 31, 2002, 4:03pm UTC](https://boards.straightdope.com/t/electronic-rust-protection/126421/5 "2002-08-31T16:03:31Z")

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doing a google search for “electronic rust protection” yields several sites - but the two most prominent products appear to be “counteract” and “electro-shield” both of which attempt to explain the “science”. curious that both seem to hail from alot of .au and .nz web addresses

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**Author:** ![bossy](https://avatars.discourse-cdn.com/v4/letter/b/58f4c7/32.png) [@bossy](https://boards.straightdope.com/u/bossy)\
**Post date:** [January 29, 2006, 5:12pm UTC](https://boards.straightdope.com/t/electronic-rust-protection/126421/6 "2006-01-29T17:12:00Z")

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Here’s a couple of links to an explanation of how this is supposed to work.

[http://www.counteractrust.com/motor%20vehicles.htm](http://www.counteractrust.com/motor%20vehicles.htm)

[http://www.counteractrust.com/capacitive%20coupling.htm](http://www.counteractrust.com/capacitive%20coupling.htm)

Does any one have a scientific comment on whether this really works ?

I’m particularly interested in whether this would work for automobiles.

thanks.