Mortar Etching on Aluminium Cill

[Andrew]

This is my own stupid fault for not covering it up, but the brickies left some mortar that had fallen onto the cill of our backdoor overnight. It looks like it's etched into the finish somehow and everything I've tried so far (fairly mild cleaning products) hasn't had any effect. 

 

 

 

Does anyone have any tricks up their sleeves for how to get this out? I've contacted the window company to see if they have any ideas but it's like a ghost ship as everyone is on holiday and I can't get a reply. They are Rationel doors so I guess it may be possible to buy replacement trims and swap them out. 

 

All the windows and doors near brickwork are now very well covered up. 

 

[AliG]

The item I often try on this kind of thing is the magic sponge which is like very fine sandpaper.

 

Do you think it is some kind of lacquer that has been damaged? That will be harder to fix. TBH I am quite OCD so would try and fix it, but if it is an outside door cill it is going to get dirty over time and I would probably live with it. We have rational doors and they have cills inside that look like that but are less shiny on the inside, they get a load of dust. mud etc on them over time.

Edited August 12, 2020 by AliG

[Reiver]

I suspect it will be a bugger to sort out I'm afraid. Most coloured aluminium is done by anodising which is a chemical  process, growing a layer of aluminium oxide on the surface of the metal and applying a dye into that layer. Unfortunately alkaline (caustic) substances such as wet concrete will eat away at the oxide layer and affect the dye. The best I can suggest is to try and find a matching non water-soluble dye (could even be a permanent marker) and apply to the affected area to see if you can get it to match: good luck. Otherwise swap the trim out.

Edited August 12, 2020 by Reiver

[Andrew]

Thanks for the suggestions. I've got a magic sponge on order along with some stuff called the pink stuff which the window company have suggested.

 

If neither work (I have fairly low hopes) then I'll have to explore swapping the trim. 

 

It does seem to be a bit of a drawback of timber frame that the expensive (and relatively delicate) windows and doors go in before the external finishes. Anyway lesson learned, everything else will be covered in clear plastic before they start near it.