Touching up black aluminium window frame

Question

I have a set of folding doors (interior <-> exterior) that have been badly scraped and scratched during a renovation project. I have purchased the correct colour touch up paint from the manufacturer, but there are no instructions on how to apply.

My initial thoughts are that I should sand down the area with 60 then 120 grade paper. Clear the area with white spirit and then apply the touch up paint. Does this sound about right? Is there a better way?

The finish of the frame is very smooth. Im worried that if I use a paint brush it will be streaky. What applicator should I use?

Note: the white area is what's left of the protective plastic, my concern is the abrasion below it.

Answer 1

do exactly what you described just as you described. put four or five coats on. then:

1) sand the new paint very carefully with 800 gr sandpaper. use wet/dry paper and use water to lubricate. use a block of wood as a backer to make sure you dont get too much pressure in one area or another and sand through the paint. sand down until smooth and flush with adjacent paint. dont worry if it looks flat and dull now.

2) repeat with 1200 and then 1500.

3) buff the repaired area and the adjacent area with a smooth cotton cloth (t shirt will do fine) with some brasso, toothpaste, or some other polishing agent. polish with hand pressure and the polishing agent on the cloth until you get the same overall gloss to match. more rubbing, more shine.

4) if a smooth finish is desired, you are done. if you want a brushed finish (like many aluminum panels) rub very lightly with a scotchbrite pad in the same direction as the grain you are trying to match.

done!

Answer 2

It depends if the doors are wood or metal and if the paint is latex or oil based.

You must get the doors very smooth, and steel wool might work best. The best way to apply the paint would be a sponge applicator, or use a brush then a sponge applicator to get the brush strokes out.

What's critical is to use the same based touch up paint as what is already on the door. You can use oil based on oil based or latex, but not latex on oil base without using a bonding agent/primer first.

Answer 3

A better easier way would be to buff out those scuffs with a buffing wheel.

If you want it optically flat, you'll need multiple coats of paint and sanding in between them.

Aluminum does not like to sand, it likes to gall, and it readily sullies sandpaper. You would need an "abrasive cleaning stick" for a larger project, but it looks like you'd only go through a few pieces of paper for that job (if any).

That being said, all you're going to do with sandpaper, is make smaller and smaller gouges: you can either buff it out, or put on so many coats of sanded paint that it just 'disappears'.