Repainting an aluminium engine block

[Walter_23]

Hi all,
I'm looking for some advice on how to clean and paint again an aluminium engine block (close up photo of a couple of pieces here: https://pasteboard.co/Vt7GRom33eCA.jpg): it seems oxidized (is it oxidized? Not sure what the white stains are).
Project is to make a showcase piece.

To clean it I'm thinking about using:
- first pass: Gunk 6868 5L Ultra Engine Degreaser
- second pass: White spirit
Good idea?

To repaint:
- I would like to avoid sandblasting or vapour blasting it (too expensive), so: would the paint stick to the stained aluminium as in the photo?
Any advice it would be really appreciated!

Thanks,
Walter

 

[sovietspybob]

I think you'll need to physically remove the oxidation, i don't think you can 'wash' it off with degreaser or the like unless they're quite harsh like oven cleaner? You'll need to either sand it or do some kind of media blasting i think otherwise the paint will just flake off.

 

[Chris Wilson]

Put them back in the sea, only something like soda blasting will do those any great good.

 

[Rroff]

Depends if you want just a show piece or a functional piece, if just a show piece you'd probably get away with hitting it with some Gtechniq W5 or W6, Jenolite rust remover and then Hammerite Direct to Galvanised Metal Paint - don't do that if you want something functional though and I'd definitely try it on a smaller bit first to see what happens.

 

[Walter_23]

Very useful comments,
I definitely need the paint to stick to it, and to stick well. So media blasting seems the way (no one is suggesting a deoxidizer as ultimate solution...).

I built a sandblaster myself and I may test it (perhaps it will be too hash on aluminium?).
I got a quote from a pro to vapour blast (more gentle than pure sandblasting?) all the 9 piece of the engine (including the engine block) for £200 (no idea if it's a good price or not).

 

[Chris Wilson]

Very useful comments,
I definitely need the paint to stick to it, and to stick well. So media blasting seems the way (no one is suggesting a deoxidizer as ultimate solution...).

I built a sandblaster myself and I may test it (perhaps it will be too hash on aluminium?).
I got a quote from a pro to vapour blast (more gentle than pure sandblasting?) all the 9 piece of the engine (including the engine block) for £200 (no idea if it's a good price or not).

It's the sort of thing I get done on a regular basis, soda blasting is your best option for sure. The medium will wash away leaving nothing down blind threaded holes, unlike sand. Vapour blasting probably won't do what you need, the castings look too far gone. What's the engine? Is it ever going to be expected to run again or definitely solely an ornament?

 

[Walter_23]

It's the sort of thing I get done on a regular basis, soda blasting is your best option for sure. The medium will wash away leaving nothing down blind threaded holes, unlike sand. Vapour blasting probably won't do what you need, the castings look too far gone. What's the engine? Is it ever going to be expected to run again or definitely solely an ornament?

It's going to be an ornament. So no functionality required but aesthetically must be spot on, and stay like that for years.
That's why my idea is to repaint it (even the grey pieces that will resemble bare aluminium), I cannot expose bare metal that will oxidize over time. But happy to take advices.

The engine is an Alfa Romeo V6 "busso" from 1998. Here the photo of all pieces: https://pasteboard.co/W4RTRdF45XCC.jpg (I will degrease them throughout).

 

[Chris Wilson]

Get it all blasted then paint the bare aluminium castings with clear matt lacquer. At least it's not magnesium, that does tend to corrode before your very eyes I found a throttle body for one of those when tidying up the other day.

 

[Walter_23]

Get it all blasted then paint the bare aluminium castings with clear matt lacquer. At least it's not magnesium, that does tend to corrode before your very eyes I found a throttle body for one of those when tidying up the other day.

Hahahahaaaa! Well glad it's not magnesium then.
If well blasted I don't have to spend on the paint (just the clear matt lacquer...).

Do you have a brand you suggest for the lacquer?