Using a Sacrificial anode on a car to suppress or at least help prevent rusting
Feb 27, 2007 57 Replies
B
Brent
I have had a thought occur to me and i could use confirmation that I am or i'm not nuts.
First off i live up in snow country and salt country, Ottawa Ontario Canada
we put enough salt on our roads up here to make the ocean seem fit to drink. And well Ottawa has one of the most aggressive snow removal and salt plans going in in the first place.
So heres my question. has anyone or is there any reason not to deliberately set up a galvanic cell by bolting an amount of magnesium or zinc to the car body in a place where the elements can hit it? IF i'm not "nucking futs" then the anode (Magnesium or zinc) getting wet touching bare steel will set up a galvanic cell with the Mg being sacrificed and "rusting/oxidizing" away to protect the steel of the cars bodywork.
Am i nuts? is this doable? does anyone do this? Just curious?
If it matters drive a unibody car with an aluminum block (diesel jetta)
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N
Nick Mueller
It works. If you make a boat out of your car. :-)
Nick
H
Harold and Susan Vordos
I may be wrong, but I'm of the opinion that unless you can achieve an electrical circuit between the sacrificial anode and body and frame work of the car and the water it holds, it won't work. The mere presence of a sacrificial element isn't enough. The navy uses a similar technique whereby a ship is one pole, the ocean the other. Same with rebar and structural steel in highway overpasses.
Harold
L
Lew Hartswick
If I'm not mistaken, I remember seeing such devices advertized years ago in some mags. I think even one of my acquaintences even had one, No idea if it worked. ...lew...
L
Larry Jaques
On Tue, 27 Feb 2007 13:46:45 GMT, with neither quill nor qualm, Lew Hartswick quickly quoth:
Lots of people swear by them and there are lots on the market.
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f'rinstance.
-- Like they say, 99% of lawyers give the rest a bad name. ------------------------------------------------------
P
prfesser
Hello Brent:
You need more than 'the elements' striking the sacrificial anode. A sacrificial anode is effective on a ship or an underground tank where the *metal**being**protected* is in direct contact with the
*solution* (ocean water or underground moisture) in which the anode is immersed.
Yeah, it kinda means that you have to drive the car under water for the anode to be effective...
An alternative is to coat the metal entirely with the anode material, as in galvanized steel.
Regards -- Terry
J
Jeff Wisnia
IIRC glvanizing steel is done for just that reason. (At least the name makes it sound that way.)
I read somewhere that even if the galvanizing is scratched through in one location the presence of the zinc adjacent to the scratch means that when the area gets wet the adjacent zinc takes the galvanic corrosion hit and "saves" the exposed steel.
Jeff
I
Ignoramus19052
What about those electric kits that are mounted on cars and are supposed to prevent corrosion. I am not sure how they could possibly work, in the absense of the electrolyte envelopig the car (like on boats), but maybe I am missing something.
i
D
Don Foreman
In order to work, the sacrifical anode must be in contact with the same liquid that is doing the corroding. That's easy in water heaters and boats, not so easy in an auto which can have isolated pockets of trapped corrosive liquid.
About the best defense is frequent washing (including "bottom blast") during salt season. My Ford Contours are 12 years old, have operated all of that time in the salty Minneapolis metro area, are completely rust free thus far. They get a trip thru the carwash after every snow, once the roads are again reasonably clear and dry.
S
stans4
VWs have been double galvanized since at least the late 80's, IIRC, as are most current cars. The problems with your concept is that you don't have total immersion in salt water, just splashes here and there. So you need a whole lot of zinc blocks, not just one or two, which is effectively what you have with the galvanizing. It won't prevent corrosion entirely, but will slow it down. Best thing is a hot freshwater rinse after exposure.
Stan
C
clare at snyder.on.ca
That's not a sacrificial anode - it's an electronic device to counter the electrolitic action. It's useless under most conditions. Daughter's Neon has one and it's rusting like all Neons.
S
starbolins
Move to California
Bud
J
Jon Elson
Exactly.
My 1989 Toyota gets washed at least once a year, and there's plenty of salt used around St. Louis. I had "the Protector" put on it for a couple hundred $ when I bought it, although the dealer made a big fuss that I was throwing MY money away, as that kind of stuff is no longer needed. There are a few rusty undercarriage pieces, but the body is totally free of any rust. The car is roughly 18 years old, driven 250+ days a year, and has 163,000 miles on it. I'm sure hot-dip galvanizing is helpful, and the new paints adhere better than the traditional finishes from the 1950's, but it seems to me that the internal coating is still the best thing you can do for long life.
Jon
I
Ignoramus19052
Jon, could you elaborate on that Protector, what is it, how it is applied, how it works etc.
i
C
clutch
[snip]
During the warmer (non snowy) months, whenever I change oil in my car, I re-paint any part of the undercarriage that shows a rock chip.
One of the issues I see with many car chassis is that the various holes trap dirt and moisture on the other side of the metal where you can't easily inspect it.
Wes
H
Howard Eisenhauer
Rather than give myself carpal tunnel syndrome again heres a link to a post addressing this issue that I made a while back on anudder group-
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This was in response to a query about Crappy Tire selling Crap. if the link doesn't work for you long story short-
Rust & galvanic corrosion are two seperate things, what works for one won't necessarily work for the other. :(
H.
Brent wrote:
E
Eregon
Nick Mueller wrote in news: snipped-for-privacy@yadro.de:
How about an Amphicar???
B
Bruce L. Bergman
Nice idea - Won't always work if you are close to the beach.
And there are mountainous areas in the state where they use a bit of salt - though AFAIK they try to use sand as much as possible.
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B
Brent
Its a good idea for other reasons. like the availability of machine tools. compared to this corner of the world I'd have likely already picked up Gunners Clausing 8540 for example at least.
B
Brent
Thats a great reply explaining it. So essentially deal with paint chips and rust spots fast and its not an issue but tossing in zinc or mg just wont cut it as an effective means of preventing corrosion thanks.
Thanks to all for the posts i'm glad it generated some discussion and I came away understanding better
B
Bruce L. Bergman
But there's a whole raft of BIG downsides - Blue state, between Frisco and Hollywood. Big taxes, big regulation, Democratic legislature and a RINO Governor (Oops!) who was supposed to clean it up but instead is playing Three Card Monte with the state budget.
(The state borrowed a ton of money with bonds earmarked to pay down public debt, and then they spent the dough and never paid it down - and new revenues are getting spent as fast as they come in. And when confronted with the facts, they deny it. If you or I tried that, they'd cart us off to prison.)
/Very/ high cost of living unless you want to commute to Taft or the other backwaters way out of town. Traffic is rapidly turning into a nightmare, even in the suburban areas and 'Rush Hour' is all day on some routes. But the NIMBY's don't want to put in a new road or widen an old one if it goes through /their/ neighborhood.
And in all industries there are a ton of crooks and charlatans you have to watch out for - who wouldn't survive a week in a small town, since word would get around and there would be no new or repeat business...
P.T. Barnum didn't figure on scale - With a big enough population base to fleece, you /can/ find enough fresh suckers that don't check references to screw over once to have a going operation.
(Plumbers getting $3K for an "emergency" water heater on the weekend
- and they make you hand-write up a form [printed ones are invalid] to get around the contract laws on 3-Day Right of Recession. So when you call around on Monday and figure out you just got screwed with the Holland Tunnel you can't do a thing about it...)
If I wasn't born and raised here, I'd seriously think twice about coming. It's not all Goodness and Light, some of that is false fronts and Hollywood set dressing.
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