What if you have welded a base material with a filler alloy that has an “A” rating for color match, but can still see the weld?
When a part is anodized, the oxide layer that is added follows the contour of the part, it does not fill in the valleys to make
a level surface. It is not possible to see the actual surface texture without the aid of magnification, but when the light reflects
off of the base material, you will see the difference.
The image below shows how the light will pass through the anodized layer and then reflect back through it - this is
where the perceived color match comes from. Wrought products have very smooth surfaces where cast products do not.
When a rolled or extruded product (wrought) is welded, the weld is actually a cast structure. Since the textures are now
different, the light will reflect differently and the weld will still be “visible” even though it is the same color.
Therefore, to make the weld as close to “invisible” as possible, you can add a texture to the entire surface. This can be
done using a variety of methods (bead blasting, sand blasting, sanding, etc.).
The Affect of Texture on Anodizing
Accomplished by selecting proper filler alloy and altering surface of the part.
Color matching is accomplished by hiding the differences.