Hello,
Saw this post and had to reply. I too play paintball and have been anodizing my own markers as well as others on my team. Parts or it are very easy and other difficult. I read over most of your questions and I can answer what I have come across my self. Might help if I know the kind of marker.
Dusting and bead blasting? No the anno does not have to be removed before this as the beadblast will remove the anno. How ever odds are you will strip it after anyways so I would do it before to prevent removing too much material. Remember to tape off any surfaces that slide, like bolt and barrel. Also once you have blasted it do not touch it with you bare hands for 1 hr or so, the grease from your fingers can appear in the finish.
I have noticed that not all the parts of a marker are made of the same grade of aluminum. Because of this I find some minor differences in color even though I do the same process.
How the color looks has allot to do with how you prepare the alumium. I use a dremel tool and a polish called autsosol to buff it.
If you like we can email info back and forth reach me at
ifeldsted@hotmail.com