anodizing/blasting

[sparts]

the parts are aluminum there blasted then sent to be anodized,after anodizing there is dirty looking areas on the parts,not always the same spot , part ,or even the same color,sometime its a dark looking dirt and sometimes its a white haze.any ideas on what it is or how to try to stop it from forming on the parts?is it something in the blasting the anodizing or what

[mcaswell]

Hard to say. I'd talk to the place you get the parts anodized. They should be willing/able to correct any finishing problems.

[mitty]

Worse thing we ever did in the shop was go down the path of bead blasting then anodizing. When ever we touched or wiped the part it would turn dark gray. We went back to our old way of prep for anodizing which is simply sanding with an orbital sander. Then we throw the pieces in a dishwasher to remove any residue and fingerprints. We anodize right after they come out of the dishwasher and have cooled down. Hope this helps

[sparts]

that was mitty that said abt the dishwasher,but its funny we use a commerical dishwasher in our process also, we use c class and ah class glass bead from potters