Aluminum corrosion spots from pH down

[2WeeksNotice]

Was using pH down (dry acid - sodium bisulfate) in a sock to get rid of waterline staining and some of it dripped onto the aluminum rail of the autocover. Tried washing with water and light scrub with Magic Eraser, but it still looks like the photo. Will aluminum continue to corrode? any way to neutralize this?

 

[JoyfulNoise]

Damage is done. Strong acids and strong bases both attack Aluminum. It would corroded any further. You might try a very fine polishing cloth or perhaps some very fine automotive polish to see if you can restore the finish.

 

[2WeeksNotice]

Thanks. Just to clarify…. Sounds like that was supposed to say “ it won’t corrode any further”??

 

[JamesW]

Once you lose the anodizing, the aluminum is at risk of further corrosion.

 

[JoyfulNoise]

Thanks. Just to clarify…. Sounds like that was supposed to say “ it won’t corrode any further”??

Sorry, my fingers got ahead of my brain …

That area IS subject to future corrosion. You can try to polish it up a bit but I would keep an eye on it.

Looks like @JamesW responded

 

[JamesW]

There is actually quite an involved process to anodize aluminum to protect it from corrosion.

Aluminum can corrode quite quickly due to its low place on the nobility ranking chart.

This is why aluminum is used as an anode to protect other metals.

You might be able to put some sort of protective coating on the damaged spots, but there is probably a good chance that the spots could corrode at an accelerated rate.

 

[JamesW]

Muriatic acid PSA

Just in case you were doubting the strength/danger of your acid 😀. Picked up a resupply of acid from Home Depot. I think the boxes got rained on because all the boxes were crumbled and most of the jugs were stand alone zip tied together to sell as packs. Picked the 4 best looking jugs and home...

www.troublefreepool.com

 

[2WeeksNotice]

thanks both...always something to learn. will keep an eye on it.