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I recognize this is a know concern but the accelerated corrosion with "brine containing MgCl2" on cars now garaged (above freezing) is IMHO not worth a ride unless you can clean car well after a drive, maybe in your garage unless you have a speedy-wash next door. Just another reason why I do not expose LG and myself therein to the stress of winter driving.

+++++++++++++

Some info/quotes from
following by Ashley Halsey III, February 22, The Washington Post.

Worse than salt, brine sprayed on roads will munch your car to pieces - The Washington Post

"Issues with car rust and corrosion are caused by acid created when a salt is dissolved by the moisture in the air. Rock salt remains a crystal until the humidity reaches 70 percent, which doesn’t happen much during the winter. But magnesium chloride dissolves when there is only about 20 to 30 percent humidity. “Which means that your vehicle, if magnesium chloride is sprayed on it, is wet constantly,” Baboian said. The acid stays on your car and slowly eats away at the paint and metal."

"So, avoid warmer garages. On a bitter cold morning a few days ago, the temperature two levels down in The Washington Post’s underground garage was 44 degrees. That temperature can support a relative humidity above 30 percent. If your car is coated with magnesium chloride, it will turn wet at that temperature: corrosion city. Chilly but not frigid in your garage at home? Same issue."

"“Inside that garage is a 100 percent time of wetness and a very corrosive situation,” said Baboian, who has written two books on automotive corrosion. “Sometimes the corrosion rate can be 100 to 1,000 times faster in the higher humidity and the higher temperature.”"


:cheers: I continue to hope that Spring will arrive soon. It was -11F here this AM. Main highways have been brine (of some type?) treated. Back roads just fine grit.
 
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That all might be so, but choosing cold garage to fight mysterious corrosion - is a questionable choice in my view. Modern cars have pretty good corrosion protection. And a warm garage is priceless in a winter like this one. My garage has radiant heat in the floor, and kept at around 68F temp. During snowstroms we drive in cars that look like one big chunk of ice, and in the morning ice is gone, and it's nice and warm.

I did not notice any accelerated corrosion, my winter beater Subie is 7 years old and just fine. Although they probably just use salt here in MI.
 

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I recognize this is a know concern but the accelerated corrosion with "brine containing MgCl2" on cars now garaged (above freezing) is IMHO not worth a ride unless you can clean car well after a drive, maybe in your garage unless you have a speedy-wash next door.
I have noticed that the salt on the road isn't leaving, despite having rained. It just sits there. I have not noticed that people really don't care and they just let their cars sit covered in salt. Some car are abandoned buried in snow.

I did not notice any accelerated corrosion, my winter beater Subie is 7 years old and just fine. Although they probably just use salt here in MI.
Subaru is no joy with rust either, as their latest recall failed to fix rust in the snow belt Subaru recalls 199K vehicles to fix brake rust | The Salt Lake Tribune. I think with the Subarus, the issue isn't so much rusting out mufflers, but the bolts, and not rot off from rust, at least that is what I have read.
 

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Thankfully they don't use magnesium chloride in my city:

"Road salts include sodium chloride (NaCl), calcium chloride (CaCl[SUB]2[/SUB]), potassium chloride (KCl) and magnesium chloride (MgCl[SUB]2[/SUB]). The City of Calgary only uses sodium chloride and calcium chloride.

"Roads salts used for snow and ice control may be solid or liquid brines. The City believes in using the right amount of salt or sanding product in the right place and at the right time.

  • When road surface temperatures are between 0 and -10 degrees Celsius, salt is used to melt accumulated snow and ice.
  • When road surfaces are below -5 degrees Celsius, a sanding chip mixture (3% salt, 97% fine gravel) is used."

Throughout most of the winter, and pretty much anytime there's a dump of snow, the temperature here is WELL below -5, so we see a lot of gravel. Lack of magnesium chloride in the salt/brine mix - coupled with more effective ant-corrosion protection by manufacturers in the past couple of decades - keeps local cars pretty much rust-free (well, visible rust anyway).

Lime-Gold, your post spurred me to check whether the "evil" chemical was used here.:thanks: That it isn't used on city roads is a relief, and explains why even 15-year-old daily drivers (local cars) don't appear to suffer any ill effects from winter usage. Anyone concerned about potential corrosive properties of the brine being used in their locale should find out if it contains magnesium chloride.
 

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calcium chloride is not used in most USA states except at very low temperatures, when sodium chloride is ineffective at melting ice. Depends on the jurisdiction, but usually not unless Temps well below +10F are expected. I've never heard of using MgCl. Porsches since the 1980s are hot dipped galvanized, so there is no issue with salt corrosion, unless u have a Porsche with major damage to the paint and zinc layers. This is not your cheapie OEMs' sheet metal. Having said all this, u could lose some of the prettiness of the aluminum alloy parts underneath, as they will tend to show pitting over time, with salt exposure.

A little warmth above outside temperature is good for corrosion protection, because it prevents condensation on the car. Moisture accelerates corrosion. The acceleration effect of increasing temperature 20-30F is negligible, if it prevents condensation.

Can u tell I'm an engineer? :gossip:
 

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Depends on the jurisdiction, but usually not unless Temps well below +10F are expected. I've never heard of using MgCl.
Its a fairly new thing, maybe from 2010. Salt Brine Causing Car Corrosion During Winter Months « CBS DC

This February has been ridiculously cold, near zero at night all the time. Last February it was constant small snow storms through Feb and Mar. Magnesium Chloride is just part of the game plan. And you can tell when they put this stuff down because it does not go away. The white from the spray just sticks to the road.

I took one of my cars to a car wash just to get the underside cleaned. It was one of the ones where you pull in and an use your own soap, just use their water because its too cold for outside water. I "thought" I got the car pretty clean. Got home, and you can see the white salt still clinging to the underneath in parts. Besides, it did no good. Just driving a few miles home and the white stuff was all over the wheels and mud flaps areas and under the wheel wells anyway. The stuff is nasty.

 

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Salt dissolved in water doesn't form acid. I'm not sure where Ashely is getting her information.

Salt corrodes because the chlorides (from sodium chloride, magnesium chloride, etc. etc. etc.) accelerate pitting corrosion at the anode.

So, it doesn't matter much which form of salt your city uses, anything with chloride will accelerate corrosion.

That being said, I think magnesium chloride and sodium chloride are a stronger desiccants than sodium chloride, so they are more likely to absorb moisture from the atmosphere and keep corroding when it's humid.

But, unless steel is actually exposed to the salt, it won't corrode. Only bare metal can corrode.

Luckily, these salts are very soluble in water, so a good undercarriage rinse should do the trick. Or, buy a de-humidifier for your garage!
 

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Twothousandandfifteen and humans have yet to come up with something that doesn't eventually destroy infrastructure and vehicles. It's a head scratcher.
 

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That's a cool piece of gear...although I don't know where I'd get running water in my -25 C garage in the winter LOL. It would be awesome the other seasons, though.
I have a hot water tap in my garage and an inside hose that I use in winter. I also have drains in my floor so I could wash inside too.
 
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