Aluminum Crazing

As crazing is due to brittle nature of oxide it is not possible to remove any damage of this type.

You may remove the oxide layer totally and reanodise if tolerances allow for this procedure.

RHABE

We often get blemishes in a black anodised finish & can often remove them with 'Brasso'. This is a very mild proprietary abrasive in suspension & a light polish hides many faults. We do this rather than re-anodising when the blemishes occur after assembly.

Thanks for the response

Just curious - does the brasso fill in the crazed area? or does the abrasive nature if the brasso break loose some of the surface oxide and that fills in the crazed area? Given the small area I would guess the polishing would not be too noticeable. I any event I will give it a try.

Thanks

Not sure about that. It only takes a light polish to improve the surface. I guess that the carrier liquid also helps to polish the surface.

Thanks for the response.

I have come upon a remedy recommended by one supplier. Thier rcomendation is a light pumice mixed with a small amount of water and the area rubbed to smooth out the crazing and blend in the oxide. I will give it a try and let you know the results.

Temporary repair rub clear coating of epoxy resin into crazed area .

Permanent repair sandblast whole item to remove anodising, wet and dry rub back surface and re anodize.

Hi,

sandblast is often too coarse and chemical removal is a possibility.

Simplest is nitric acid (HNO3) that attacks the oxide fast and the aluminum slowly.

There are other possibilities to remove the oxides - I forget about, but I have some books to look into.

RHABE

You can use caustic soda (Sodium hydroxide (NaOH), also known as lye) to strip anodising but it will attack the base metal & generate hydrogen gas so much care is needed.