[SOLVED] Fix Scratch on Case

Solution
Depends.

The hard part isn't matching the scratch, it's the surrounding area and whatever surface coating is on the aluminium. Many times it's anodized, to harden the aluminium and offer some protection from scratches etc but that's a coating that's almost impossible to replace without special tools and equipment. So if the surface is anodized, you are out of luck.

Sometimes it's just a clearcoat paint, really thin but protects the aluminium from oxidizing. If that's the coating, you could buff out the scratch and give it a quick shot of clear then use a clay bar to remove the overspray and blend it back in.

If it's pure aluminium, no coating, that can be the hardest to repair because there's no coating to hide imperfections. Most...

Karadjgne

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Depends.

The hard part isn't matching the scratch, it's the surrounding area and whatever surface coating is on the aluminium. Many times it's anodized, to harden the aluminium and offer some protection from scratches etc but that's a coating that's almost impossible to replace without special tools and equipment. So if the surface is anodized, you are out of luck.

Sometimes it's just a clearcoat paint, really thin but protects the aluminium from oxidizing. If that's the coating, you could buff out the scratch and give it a quick shot of clear then use a clay bar to remove the overspray and blend it back in.

If it's pure aluminium, no coating, that can be the hardest to repair because there's no coating to hide imperfections. Most use everything from steel wool to a scotch pad to a wire brush, even using a wire wheel on a dremel. But replacing the 'brushed' look and getting the refraction angles right is a nightmare. Get it wrong and from one angle the repair is invisible and 'gone' yet from another angle shows up like a full moon in a star less sky.

At a minimum, I'd say a lot of time and patience with a X-acto knife might be the best bet. Use a magnifying glass and ruler and recreate the vertical 'brush' lines. The scratch is visible because of the change in the 'peaks' of the brush, if you re-do the brush, the scratch loses its affect, pushing the 'peaks' back straight.
 
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Solution

InvalidError

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Sometimes it's just a clearcoat paint, really thin but protects the aluminium from oxidizing.
Aluminum does not need anodizing for protection, it almost instantaneously oxidizes in air and that oxide layer requires no further treatment to resist most common chemicals.

As for fixing a scratch into a brushed finish, the only way to completely get rid of the scratch would be to polish the whole thing until the scratch is gone, then re-brush it. If you try to only rework the damaged area, you are unlikely to be able to match the original brushed look and end up with an even larger spot of dissimilar finish and now you will have even more polishing work to do to blend your reworked area into the rest of the original brushed finish to minimize visible distortions.
 

Karadjgne

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FREQUENTLY ASKED QUESTIONS ABOUT ANODIZING

WHAT IS ANODIZING?

Anodizing is a process for finishing aluminum alloys that uses electrolytic oxidation of the aluminum surface to produce a protective oxide coating. The anodic coating consists of hydrated aluminum oxide and is considered resistant to corrosion and abrasion. Coatings are 0.1 to 1.0 mil thick and are essentially transparent, although they may be colored. Unlike most other finishes, anodizing preserves the natural luster, texture, and beauty of the metal itself. The anodized coating is hard, durable, will never peel, and, under normal conditions, will never wear through.


WHAT IS THE PURPOSE OF ANODIZING?

The purpose of anodizing is to form a layer of aluminum oxide that will protect the aluminum beneath it. The aluminum oxide layer has much higher corrosion and abrasion resistance than aluminum. There are some types of anodizing that produce a porous oxide layer that can be colored with organic dyes or metallic pigments giving the aluminum a decorative and protective finish. In short, the main purposes for anodizing are corrosion resistance, abrasion/wear resistance, and cosmetics.
This is why you need to be very careful when cleaning aluminium car rims, you need to use a pH neutral cleaning fluid because the rims are anodised and alkaline/acid based cleaners will stain the aluminium and it can't be removed without destroying the finish. Natural aluminium is quite soft, scratches and dents easily, a fingernail can gouge it.
View: https://youtu.be/Y8JG6RSUwEA
Lian-Li anodizing factory btw.
 
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That looks more like a mark in a clear coat finish that a scratch. If anything I’d take the gentlest approach. Using a pure cotton rag. Dipping it in soapy water. Wring it out. So it isn’t dripping. Then rubbing it.

Take a look at it when wet. If it looks good when wet. You might get away with car wax.. maybe buffing it with a gentle car polish. Then waxing the whole panel. Always do everything with the grain. Test in an inconspicuous spot first.

You’ll never get it perfect. Outside of sanding and painting the whole thing. Which will make it look different.