What's the latest recommendation for removing corrosion stains from road salt?

[canyoncarver]

So I picked up some of the foaming barkeepers friend and gave it a shot. Before/after photos shown.

I have WD40 I could try but honestly I'm a bit leery of being the guinea pig on that one unless someone with direct experience can comment further.

I was able to remove a decent amount of the very noticeable staining in just 30 seconds with the BKF foam and a microfiber rag. Prior to application I washed this part of the bumper with a "washless" detergent (very tiny amount) added to some room temperature RO water.

I think with a little more effort I might be able to remove the rest of it.... however, it's 30F outside and it's going to be snowy and below zero in just a few days so probably won't waste my time right now as it's going to get nuked again in less than a week's time.

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[RickJ19Zeta8]

Barkeepers friend (foam) is oxalic acid. Citrisurf 77 (recommended by Tesla btw) is citric acid. They both work similar, but not identical for the cleaning step before passivation. Passivation as stated by HaulingAss, is the oxidation layer that develops AFTER you clean it.

Oxalic acid will dissolve into solution the surface free iron AND chromium. (very thin layer). And then you will end up with oxidized iron (yellowish brown hue) and chromium oxide (green/blueish hue) during passivation from the remaining surface layer that was clean. BOTH protect the underlying stainless steel, but can over time show up as the more patina yellowing look. And if you let the dissolved iron oxalic acid solution dry on the surface, it will tend to deposit iron oxalates (yellow/brown) which are very difficult to remove later.

Citric acid biases dissolving of the surface free iron /iron oxides and NOT chromium. This effect leaves a very thin layer of chromium, that oxidizes to chromium oxide (green/bluish hue). Nitric acid has the same effect, but you don't want to work with that.

The stainless steel surface treated with citric or nitric acid will have a more uniform silver / blueish green hue that stays that hue longer without yellowing. This is why ASTM976 or other passivation specs call out citric or nitric acid and NOT oxalic acid. And its why you see people complain that the truck yellows / patinas after awhile after they clean it with BKF.

Personally, I did my truck with Citrisurf 77 once. I havent had to touch it again in 6 months other than an occasional wash. I will probably clean it again in spring with Citrisurf to clean off any brake dust / iron fallout if I see any.

 

[canyoncarver]

Thanks for the information. I was not able to find a place to buy Citrisurf 77 locally. I have to take my truck in next Monday so perhaps Tesla will have some at the shop they will sell to me.... otherwise I would have to mail order it.

 

[M0unt41nm4n]

So I picked up some of the foaming barkeepers friend and gave it a shot. Before/after photos shown.

I have WD40 I could try but honestly I'm a bit leery of being the guinea pig on that one unless someone with direct experience can comment further.

I was able to remove a decent amount of the very noticeable staining in just 30 seconds with the BKF foam and a microfiber rag. Prior to application I washed this part of the bumper with a "washless" detergent (very tiny amount) added to some room temperature RO water.

I think with a little more effort I might be able to remove the rest of it.... however, it's 30F outside and it's going to be snowy and below zero in just a few days so probably won't waste my time right now as it's going to get nuked again in less than a week's time.

I have the exact same issue. Lots of mag chloride spots. ? But cleaned some and then I go out during a snow storm and back they come. It’s futile. Im gonna just wait until Spring and a few rain storms to bleed that mag chloride into the ditches and get the road cleaner. Then I will go to town with BKF.

 

[canyoncarver]

I have the exact same issue. Lots of mag chloride spots. ? But cleaned some and then I go out during a snow storm and back they come. It’s futile. Im gonna just wait until Spring and a few rain storms to bleed that mag chloride into the ditches and get the road cleaner. Then I will go to town with BKF.

Yeah, it's kind of sad. I expect a future update of the Cybertruck will do something to address this, but for now the only options are to live with it or to wrap it.

 

[M0unt41nm4n]

Barkeepers friend (foam) is oxalic acid. Citrisurf 77 (recommended by Tesla btw) is citric acid. They both work similar, but not identical for the cleaning step before passivation. Passivation as stated by HaulingAss, is the oxidation layer that develops AFTER you clean it.

Oxalic acid will dissolve into solution the surface free iron AND chromium. (very thin layer). And then you will end up with oxidized iron (yellowish brown hue) and chromium oxide (green/blueish hue) during passivation from the remaining surface layer that was clean. BOTH protect the underlying stainless steel, but can over time show up as the more patina yellowing look. And if you let the dissolved iron oxalic acid solution dry on the surface, it will tend to deposit iron oxalates (yellow/brown) which are very difficult to remove later.

Citric acid biases dissolving of the surface free iron /iron oxides and NOT chromium. This effect leaves a very thin layer of chromium, that oxidizes to chromium oxide (green/bluish hue). Nitric acid has the same effect, but you don't want to work with that.

The stainless steel surface treated with citric or nitric acid will have a more uniform silver / blueish green hue that stays that hue longer without yellowing. This is why ASTM976 or other passivation specs call out citric or nitric acid and NOT oxalic acid. And its why you see people complain that the truck yellows / patinas after awhile after they clean it with BKF.

Personally, I did my truck with Citrisurf 77 once. I havent had to touch it again in 6 months other than an occasional wash. I will probably clean it again in spring with Citrisurf to clean off any brake dust / iron fallout if I see any.

That Citrisurf 77 is expensive! It's like $32 for 22 oz!

Fun fact:

Cirtisurf 77 is just pure citrus acid at 15% solution with water as per the MSDS:

https://static1.squarespace.com/sta...045eda3761/1638573511699/SDS+CitriSurf+77.pdf

So for 32oz (about the size of a standard windex bottle) of home made Citrisurf 77, you use a little over 1/2 cup (or 4.8oz to be exact) of citric acid to 32oz of water which will give you a 15% solution. Or, use 2.4 cups (20 oz) per gallon of water. On Amazon you can get a 10 lb bag of citrus acid for about $35 (or maybe even cheaper). So by making it yourself, for the same amount of a 22oz of Citrisurf 77, you can make 4.16 gallons of this... or about 24 CirtiSurf 77 22oz bottles.

 

[canyoncarver]

That Citrisurf 77 is expensive! It's like $32 for 22 oz!

Fun fact:

Cirtisurf 77 is just pure citrus acid at 15% solution with water as per the MSDS:

https://static1.squarespace.com/sta...045eda3761/1638573511699/SDS+CitriSurf+77.pdf

So for 32oz (about the size of a standard windex bottle) of home made Citrisurf 77, you use a little over 1/2 cup (or 4.8oz to be exact) of citric acid to 32oz of water which will give you a 15% solution. Or, use 2.4 cups (20 oz) per gallon of water. On Amazon you can get a 10 lb bag of citrus acid for about $35 (or maybe even cheaper). So by making it yourself, for the same amount of a 22oz of Citrisurf 77, you can make 4.16 gallons of this... or about 24 CirtiSurf 77 22oz bottles.

I mean these trucks cost an arm and a leg, I'm not going to lose too much sleep about saving $20 on buying a pre-made citric acid cleaner vs mixing up my own.

 

[M0unt41nm4n]

I mean these trucks cost an arm and a leg, I'm not going to lose too much sleep about saving $20 on buying a pre-made citric acid cleaner vs mixing up my own.

Yeah for one bottle which is pretty easy to use up in 1 single washing, it may not be worth it.

You can easily use 24 of those bottles over a year. Totally savings is $728.00.

I dunno about you... but it takes about 45 seconds to whip up a bottle and over the course of that year, that $728 can go towards a sweet item for your Cybertruck.

It's not like it takes you an hour make this stuff.... yes... about 45 seconds.

 

[canyoncarver]

Yeah for one bottle which is pretty easy to use up in 1 single washing, it may not be worth it.

You can easily use 24 of those bottles over a year. Totally savings is $728.00.

I dunno about you... but it takes about 45 seconds to whip up a bottle and over the course of that year, that $728 can go towards a sweet item for your Cybertruck.

It's not like it takes you an hour make this stuff.... yes... about 45 seconds.

Well, for best results you should probably use distilled water, I'm not sure what the results will be with just regular filtered tap water.

I agree though if it turns out you are using a lot of it then it might make financial sense.

I only plan on using this stuff after snow/salt season is over.

 

[M0unt41nm4n]

Well, for best results you should probably use distilled water, I'm not sure what the results will be with just regular filtered tap water.

I agree though if it turns out you are using a lot of it then it might make financial sense.

I only plan on using this stuff after snow/salt season is over.

In theory, it should be fine using hard water. Citrus breaks down calcium deposits similar to vinegar. Thats said, I would agree, distilled probably would be better to be safe than sorry.

Me too... just for winter. During the warm months my CT was sparkling clean If it got dirty after a rain, soap and water and maybe a bit of Spray Away made it look new again.

 

[M0unt41nm4n]

So I ordered some citric acid and a Zep bottle from Amazon. Mixed myself up a nice batch of 40oz today, and it seems to work pretty good!

I decided to do a bit of Googling to be sure I was on the right path.. and it led me to this great article regarding citrus acid and stainless steel cleaning:

https://www.practical-sailor.com/boat-maintenance/passivating-stainless

I followed the Cirtsurf 77 and that article's instructions... letting it soak for a bit before washing it off... it did a nice job.

I will keep this up a bit this winter and see how it fares.... but so far I think this is a good poor-man's Citrisurf 77.

 

[canyoncarver]

Just an update.... Citrisurf 77 is useless for removing these corrosion spots.

So, I will have to plan on going over the truck with barkeeper's friend and possibly even get out my orbital to get it all off.

I'm now contemplating some kind of coating for the steel as the CT clearly can't take the winter road conditions here and I have no plans on wrapping it.

 

[canyoncarver]

So I ordered some citric acid and a Zep bottle from Amazon. Mixed myself up a nice batch of 40oz today, and it seems to work pretty good!

I decided to do a bit of Googling to be sure I was on the right path.. and it led me to this great article regarding citrus acid and stainless steel cleaning:

https://www.practical-sailor.com/boat-maintenance/passivating-stainless

I followed the Cirtsurf 77 and that article's instructions... letting it soak for a bit before washing it off... it did a nice job.

I will keep this up a bit this winter and see how it fares.... but so far I think this is a good poor-man's Citrisurf 77.

How long did you keep it soaked before you wiped it off? Did you use something mildly abrasive like a clay detailing pad or blue scotch brite pad?

What temps were you working in?

I tried cleaning corrosion off of a door panel as a test and spraying Citrisurf77 directly on the panel, waiting 20 seconds and wiping it off did not do very much. Temp in the garage probably 40F.

 

[M0unt41nm4n]

How long did you keep it soaked before you wiped it off? Did you use something mildly abrasive like a clay detailing pad or blue scotch brite pad?

What temps were you working in?

I tried cleaning corrosion off of a door panel as a test and spraying Citrisurf77 directly on the panel, waiting 20 seconds and wiping it off did not do very much. Temp in the garage probably 40F.

About 15 minutes. Temps in my garage were about 58. I believe the Citrisurf 77 also says 15-20 minutes and keep it wet. You can keep it wet by putting paper towels soaked in it. After that be sure to use water with a sponge to remove it all or it will get sticky. I pretty much followed the citrisurf 77 directions. You will know it’s working if the sponge has black on it. That’s the tarnish coming off. Use elbow grease too.

 

[canyoncarver]

About 15 minutes. Temps in my garage were about 58. I believe the Citrisurf 77 also says 15-20 minutes and keep it wet. You can keep it wet by putting paper towels soaked in it. After that be sure to use water with a sponge to remove it all or it will get sticky. I pretty much followed the citrisurf 77 directions. You will know it’s working if the sponge has black on it. That’s the tarnish coming off. Use elbow grease too.

Alright I might give it another shot. Having a bunch of wet paper towels clinging to the car seems suboptimal though.

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