What Chemical to Use for Removing Salt / Oxidation from Cast Aluminum

[asphaltgambler]

I want to remove the 'crust' of heavily oxidized aluminum (outside) engine parts. Specifically, the engine / components sitting in the engine bay. It's not practical to hand scrub as you can't get to everything.

So it needs to be basically sprayed on, washed off with water. I see a lot of products but have no direct experience if they will work for my problem.

Advice please...……….

[masraum]

My understanding is that aluminum oxide is HARD, much harder than raw AL. I believe it's considered a protective coating. I'll be curious to see what the experts say on this thread.

[island911]

Steve is right. It is hard. But unless it is also sealed the 'pours' collect all kinds of stains.

Some use oven cleaner on the cheap.

[island911]

Just checked, and of course there are a bunch of tube-vids on that. https://youtu.be/Kk2jO863-yI

[LWJ]

Aluminum is unique in that it reacts to acid as well as base. Start mild and work your way up. If you remove the oxide layer, the aluminum could get an odd dark grey hue.

I would start with simple pressure washing. A mechanical removal sounds like it won’t work. So that leaves chemical. Go slow. Simple Green and Power Purple both can remove a little aluminum.

[herr_oberst]

Originally Posted by LWJ

Simple Green and Power Purple both can remove a little aluminum.

I ruined an aluminum derailleur once with Purple, I left in in too long. Chomp.

[Bill Douglas]

Caustic soda (sodium hydroxide) rips into aluminium. As to whether or not it takes the oxidisation off first I don't know. But this is the active component of harsh oven cleaners that are sometimes used for cleaning up aluminium. Good luck with the project.

[arcsine]

As mentioned, aluminum oxide is hard and subsequently hard to remove. There are any number of corrosive cleaners that can be applied with associated risk to the person doing the work and release of caustic run-off into waste streams. In most of these circumstances physical brushing or scrubbing would be required as well, increasing the exposure risk to the worker.

In my feeble opinion, bead (or sand) blasting would be less toxic if available. Alternatively if there is a commercial cleaner in your area that could dip the parts at least the exposure to corrosive chemicals would be contained and minimized.

[fxeditor]

I just asked Garry Dean, The provider of the vast majority of my detailing products, what he'd use and this is what he said:

Do you have any Tigers Blood he can try? (I'm sorry but I don't). it's a very powerful degreasing cleaner. It is for the heaviest of duties. Engines and the such. TB is super strong at 1:3 dilution. Tell your friend that if he should want to order a bottle of TB, to leave a message saying I said I'd also include some IPC (Infinite Purpose Cleaner, another of his products) to see if that gives him the product he needs.

I hope this helps you!

BTW, he's running a Thanksgiving promo 25% off and free shipping for orders over $79.00 Use promo code "thanks25" at checkout (just in case).

Edit: Typo

[Shaun @ Tru6]

spray Easy Off oven cleaner on, wait 1 minute, hose off thoroughly.

dry and repeat until you are satisfied.

do NOT let the oven cleaner stay on.

[flatbutt]

Maybe Simple Green?

[unclebilly]

Originally Posted by Shaun @ Tru6

spray Easy Off oven cleaner on, wait 1 minute, hose off thoroughly.

dry and repeat until you are satisfied.

do NOT let the oven cleaner stay on.

I have heard of this before as well but never tried it.

You could try aluminum wheel cleaner and follow the instructions.

[OK-944]

I've had pretty good luck with Eagle One Mag Wheel Cleaner...finding that an initial light cleaning with something else (your favorite brew) to remove any dirt/grime/grease - rinse and allow to dry...then spray on some Eagle One, let it sit for a minute or so - then use a stiff non-metallic brush to work it in well prior to spraying off with water. Important that you don't leave any of this stuff on for too long.

At any rate...this worked well for my 944's engine (which I had out in parts for rebuilding), the bottom cross member, and control arms. Really brightened things up nicely.

I also gave a very light "after spray" with WD-40 - mostly to help protect my engine once assembled, as it then sat in my garage through most of last winter prior to my reinstalling it in the spring. Upon startup, the WD-40 burned off fairly quickly and painlessly - but seems to have left a very light protective film.

Thing is, I would hesitate to use a product like Eagle One on an installed engine - as access to all of the nooks and crannies can then be a bit difficult - and the risk of leaving harmful caustic chemistry behind is much higher.

[asphaltgambler]

Thanks all, yes Eagle 1 Mag / cast aluminum cleaner seems to effective but with relatively low risk. If that doesn't work I'll try ratcheting up to some of the more serious suggestions above.

[rcooled]

Originally Posted by island911

Some use oven cleaner on the cheap.

I tried this once and it left a blotchy dark gray finish on the aluminum. Might've left the cleaner on too long...

A local guy had this VW engine case vapor blasted after it sat outside half-buried in muck for 20+ years. Now this case is magnesium, and I don't know if aluminum can be treated in the same way, but it might be worth looking into.



https://www.raptorblaster.com/what-is-vapor-blasting-wet-blasting/

[rfuerst911sc]

In the past I have stripped Fuchs aluminum wheels with Easy Off oven cleaner . Use the yellow can it has the most lye in it . Stripped the anodizing right off then I polished them .

Eye protection and gloves recommended , it's nasty stuff . Remove it before it dries . Outside but in the shade is recommended for ventilation you don't want to breathe that crap in an enclosed space.

[javadog]

Some aluminum alloys will turn a dark gray if you use sodium hydroxide on them, I think the 6000 series alloys are like that. The gray coating can be removed by lightly abrading it.

As with an acid wash, spray it on a limited area, work it mechanically somehow and rinse it off that early. Don’t let it sit.

I’m cleaning up some aluminum parts that are of a Japanese 7000 series alloy, as we speak. Sodium hydroxide and a gray Scotch-Brite pad.

In progress on the left, before on the right:

[asphaltgambler]

Thanks!