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NoExpertAtAll t1_j65euqd wrote

Simply said:Rusting is a process in which electrons must be released from the iron. The more charged ions present, the easier this is, as the conductivity of water (rain, melted snow) is increased. Road salt is a wild mixture of sodium chloride, magnesium chloride and other salts. This massively increases the conductivity of water, making it easier to rust.

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Krispy_Kolonel t1_j65h9ct wrote

It’s the same reason things rust faster at the beach or in the ocean. More salt=more conductivity, increasing the rate of the reaction (oxidation or rusting in this case)

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_Greetings_Friends_ t1_j66t529 wrote

When I was a kid there was a busted down VW bus that was just kind of left on the beach as debris but it was atleast fairly unworn, I went there a couple years back and the bus was still there but theres now a gaping hole in the top and every last inch of it is covered in rust or somekind of plantlife, the saying "It was a shell of its former self" is so real, it had only been about 10 years but if left in my yard 10 years it would be nearly identical

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hans-and t1_j67ifdn wrote

Yes same reason as to why you can use saltwater, copper and zinc to make a simple battery, and the reason you attach zinc sacrificial anodes to ocean going ships

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jonathanrdt t1_j68dk1f wrote

Is it also a function of the added moisture? Salty things don’t dry easily.

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pretty_kitty_808021 t1_j6689u0 wrote

Dry salt itself won't, but when mixed with moisture, it becomes extremely corrosive. Saltwater is likely to cause metal to rust about five times faster than freshwater. Saltwater is a solution that acts as an electrolyte, allowing the metal to lose electrons faster. Rusting is caused by oxidation, where the metal loses electrons and produces ions. Therefore the presence of salt in a wet environment, speeds up the process.

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it00 t1_j66asdj wrote

Any form of salt accelerates corrosion in any form of steel, iron, well, pretty much anything (yeah, including certain types of 'Stainless Steel').

If you live next to an ocean or sea you'll know all about it - hint: DON'T buy a car or machinery from an island area.

Salt mixed with water and oxygen will simply accelerate corrosion beyond belief - it accelerates the transfer of the electrons from pure iron to form iron oxide. For an example take a look at ladder irons on a tidal quay, pier or shore structure. The rungs permanently underwater will be OK(ish), the rungs halfway up will be pretty badly corroded, the rungs above the water will be utterly destroyed. It needs all three elements to make rust - iron, oxygen, sodium chloride.

Where all three are present in sufficient quantities they can literally reduce an entire vehicle to oxidised nothingness within a decade. This includes entire engine blocks etc.

Roads are optional.

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PlaidBastard t1_j68wnji wrote

Puget Sound in WA state is a good exception to this, because the water is less salty and probably because the constant rain keeps the air from getting brackish.

Seriously, cars don't rust here. Sunroofs leak and mildew destroys them from the inside, but the green algae usually scrubs right off to reveal shiny clearcoat....

Then you go 50 miles west to the actual Pacific coast, and everything you say about rust is true again...

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it00 t1_j68yx3y wrote

I took a ferry near Puget Sound on a road trip in 2018 - from Clinton to Mukilteo - is it Possession Sound? Genuinely just thought it was a regular sea crossing - I suppose looking again at the map that area is more like a river than a regular seaway.

The rain held off for the most part - although the greenery was spectacular compared to the other (?rain shadow) side of the Cascades. Lovely part of the world. Good you don't get the rust problem - same here in Scotland. In the sea lochs it isn't a problem - on the coast and islands on the other hand...... it's hellish!

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