Tips For Cleaning Up Surface Rust In Engine Bay

[Muzez 38]

Getting setup for some winter projects for my 1977 280z including a deep clean on the engine bay since the last owner left a lot of grease build up and cosmoline. I have a number of places, usually near welds and seams, where I have small pockets of surface rust like shown in the picture (usual Datsun rust issues 😕 ) . Anyone have any advice for the best way to remove this and stop it from coming back? 

I am planning to repaint the car between 2021 and  2022 which will include engine bay paint, but want to at least stop the progress of the rust between now and when I can give it a more thorough blasting.  I have used naval jelly before on parts outside of the vehicle, but not sure if that is the best approach here since there is a lot of intact paint I would prefer not to disturb before repainting. 

[siteunseen 3,432 5 Vehicles]

I've had good luck with S.EM's rust inhibator. It turns the rust black but stops it dead in it's tracks.

 

 

[grannyknot 1,819 2 Vehicles]

An aggressive wire wheel is what I would start with, also 3M makes a paint/rust stripping disc that works well too.

 

[Yarb 47]

@siteunseen, Does that product need to be neutralized after the application?

[siteunseen 3,432 5 Vehicles]

20 minutes ago, Yarb said:

@siteunseen, Does that product need to be neutralized after the application?

I didn't apply anything. After I posted that I sort of recall reading it was some type of acid in the mix that caused it to blacken. Google it and get a quick read on it. It was given to me by a car painter for the rust on a 240 I bought and sold without repainting. He said use that and let the next buyer decide on paint. I just drove it for a few years. 

[grannyknot 1,819 2 Vehicles]

5 hours ago, Yarb said:

@siteunseen, Does that product need to be neutralized after the application?

That is another phosphoric acid product. After it has done it's thing it has to be washed off with water, if it dries on the metal it has to be reactivated and then washed off.  There's another thread going right now about the pros/cons of certain acids.

 

[Muzez 38]

1 hour ago, grannyknot said:

 There's another thread going right now about the pros/cons of certain acids.

 

Thanks @grannyknot it was this thread that originally triggers my thought but I figured with citric acid being an aqueous solution, it would be hard to use outside of a controlled environment like a container. No? Also good call on the sanding disks. 

Also, thanks @siteunseen for the recommendation! 

[grannyknot 1,819 2 Vehicles]

47 minutes ago, Muzez said:

Thanks @grannyknot it was this thread that originally triggers my thought but I figured with citric acid being an aqueous solution, it would be hard to use outside of a controlled environment like a container. No?

Well this German product that I mentioned at the beginning of the other thread is what started me experimenting with citric acid in the first place.

That product has citric acid suspended in a wet paste that you can apply to a vertical surface, you cover it with cling wrap to keep it from drying out and wipe it off when it has removed the rust.  Now being a the cheap bugger that I am I wasn't going to pay German prices for something I could perhaps make myself in the laundry sink, I still haven't attempted it yet but I was thinking a mixture of sawdust, glycerin and citric acid power might make a paste like product to experiment with.

[Zed Head 2,203]

How about a blender and a bucket of lemons?

AK260'z Jenolite uses lactic acid.

https://www.classiczcars.com/forums/topic/64766-citric-acid-and-rust/?do=findComment&comment=611145

https://jenolite.com/pdf/rust-converter-msds.pdf

[grannyknot 1,819 2 Vehicles]

8 hours ago, Zed Head said:

How about a blender and a bucket of lemons?

AK260'z Jenolite uses lactic acid.

https://www.classiczcars.com/forums/topic/64766-citric-acid-and-rust/?do=findComment&comment=611145

https://jenolite.com/pdf/rust-converter-msds.pdf

I did the same thing last night and looked up the MSDS for Jenolite and the one I found said orthophosphoric acid.

http://www.farnell.com/datasheets/1496472.pdf

 

[Zed Head 2,203]

That's the Remover. AK260's was the Converter.  

https://jenolite.com/about-us/faq/