Electronic Rust protection for cars?

I have seen some devices advertised claiming to prevent or slow down rust in cars? Is this possible? I know some of them are obvious frauds, but some use a sacrificial anode and some electronic driving them. Are they worth the modey and do they work?

Reply to
Aldo
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I don't think much has changed since the 90's

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And here is the opinion of Leo Simpson, editor of Silicon Chip magazine.

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While elctronic corrosion protection will work on marine vessels I tend to agree with Leo regarding automobiles....

Reply to
Ross Herbert

I was also always sceptical about this too; and still am. But while I believe normal and common industrial cathodic protection (based on a sacrificial anode immersed in water) won't work on cars due to the lack of a water medium there is another form of electronic protection called anodic protection that appears to be soundly based scientifically and engineering wise and if a suitable medium coating is applied to the car's body both cathodic and anodic protection may well work. Some sellers of these devices do also claim to coat the card with a special medium, (but I wonder in this is just really rust preventing deodorised fish oil rather than a conductive medium)

What makes me wonder if anodic protection at least might be made to work on a car is a quote from the well regarded Bosch - SAE (Society of Automotive Engineers) Automotive Handbook (6th edition in this case but similar things are in earlier editions) ' ...another option [to cathodic protection which moves the potential so no anodic current flows or using a sacrificial anode] is to shift the potential of the threatened electrode into the passive range between Up and Ud. This is called anodic protection. The anodic currents, which flow in the passive range , are less than those in the active range by exponential powers of between 3 and 6, depending on the type of metal and the corrosive medium. The result is excellent protection for the metal. However, the potential should not exceed Ud as oxygen would be produced in this transpassive range, potentially leading to higher rates of oxidation."

Certainly some sellers of these electronic corrosion protection devices claim that as the use anodic protection the lack of a suitable medium isn't an issue. See

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'The anodic protection provides significant reduction of the formation of corrosion to painted and unpainted surfaces, proven by independent laboratory tests conducted in accordance with ASTM procedures for the testing of corrosion resistance in the presence of salt fog and extreme humidity. "

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Blue
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Reply to
aussiblu

And have a look at these patent documents:

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?vid=USPAT4226694&id=QLQ6AAAAEBAJ&printsec=abstract&zoom=4&dq=automotive+anodic+corrosion+protection--RegardsBlueRemove ZX from email address to reply directly.

Reply to
aussiblu

That was meant to be :

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and

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and

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Blue
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Reply to
aussiblu

Interesting.

Exactly as described, opinion. Not worth a pinch of shit.

Passive protection is usually used in marine applications. I have never seen a commercial vessel with electronic protection. They do it the hard way with anodes and paint/coatings.

I do remember doing a module at uni on corrosian mitigation, and i faintly remember the lecturer there describing exactly why these mechanisims do not work. I cant really remember how it works but a quick flick through materials sites on the web and one quickly notices the absence of electronic protection theories.

If anyone can remember the different forms of corrosion and the good ol' redox reductions then they will quickly find the answer. Perhaps this thread could be crossposted to a good chemistry group (i dont know of any).

Reply to
The Real Andy

and

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and

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NB The existence of these patent documents doesn't mean any of them actually work but they do explain how they are meant to work.

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Blue
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Reply to
aussiblu

I have seen cathodic protection used commercially to protect steel pylons in jetties (eg the WA Jervoise Bay/Cockburn Sound Offshore Construction site) and bridges. It is also used with storage hot water systems with sacrificial anodes. But both applications have a water medium to work in. I also believe it is commonly used with steel hulled ships and underground pipelines but all these too exist in a wet medium.

Perhaps if you and you car live in Hobart or Melbourne there will be enough constant rain for it to work (an irresistible cheap shot from a west aussie I know; sorry).

There seems no end of patents for car based system; another vehicle related patent is

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Blue
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Reply to
aussiblu

Just reading a materials book I have. The section on corrosion is very breif, but it shows the use of electronics corrosion protection with large, buried liquid fuel tanks. It is very different to the 'auto ERP' systems given the fact that they still use sacrificail anodes.

This book refers endlessly to another book called 'Corrosion Engineering' by M.G Fontana. Anyone have a copy?

Reply to
The Real Andy

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keeps it relatively simple but provides some very good answers

Reply to
The Real Andy

I put all automobile electronic corrosion claims in the same bag as magnetic fuel saving devices.

While there are no brand names used in this article the conclusion appears to be that electronic corrosion control does not work

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Reply to
Ross Herbert

When we purchased a new car in 2005 one of the overpriced aftermarket products the dealer tried to sell us was electronic rust protection. On a new car! They also offered tinting at about twice the price of a known brand. The chick spruiking their wares looked incredibly bored, she probably does this all day. :)

We declined all offers. We just want the car thanks.

Reply to
rowan194

They tried telling me that if a bat decided to shit on the duco, the shit might eat through the paint, and the paint protection (thats part of this stupid overpriced package) will protect against this.

My reply was that the paint must be pretty shit quality to be that easily damaged, and that Im not the sort of feral person to just leave a turd sitting on a new car for weeks to let it eat through the paint.

I eventually bought the car at another dealership, and saved about $1500. They didnt try to sell me the package of extras for some reason.

101,040 km and 5 years later, the unprotected paint is still in beautiful condition :)
Reply to
kreed

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CRap re weather in Melbourne being wet. We all wish it were.Theres a drought. But on average you havent even figured out the SYDNEY usually gets more H2O than Melbourne. And more lightning and hail storms. Hobart gets wet and cold and rust works well in the windy city.

Reply to
Jonno

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