Question about re-anodizing a part

[bac0nfat]

I have a long length of picatinny rail (about 15" long) that was anodized from the factory, but I have since cut it to length and drilled several holes in it, among other modifications. Now most of the rail is still anodized but there are several spots that are bare aluminum. I want the whole thing to be uniformly anodized black, what is the best way to go about doing that? I have access to a sandblaster, but I'm concerned that sandblasting will leave a rough texture that will show right through the anodizing. I want a more clean, factory finish look. Is it possible to re-anodize the whole thing without actually removing the existing anodizing? Or is there a chemical process I can use to remove the existing anodizing? Could I sandblast it, but then do something to smooth out the finish? Any other thoughts?

Also, please don't suggest using aluma-black or some other touch-up paint. I want this to look good.

ETA: What about sandblasting and then polishing on a buffer wheel?

[normanvin]

There are a few different types of media you could use to sand blast it. Walnut shells come to mind.

[Shodan]

I assume you are sending it out for annodizing, not doing it yourself? If you are going to send it out, have the annodizing company strip it for you before they annodize the part.

If you have to do it yourself for some reason, I've heard vinegar will remove annodizing without too much risk of damaging the part. You can sand it off to with care and patience.

Good luck.

[bac0nfat]

There are a few different types of media you could use to sand blast it. Walnut shells come to mind.

Right now we have aluminum oxide in the sandblaster. If I have to change out the media, I'd rather just have someone else do the whole thing. It's not worth the hassle of buying the media and changing it out, just for one part.

I assume you are sending it out for annodizing, not doing it yourself? If you are going to send it out, have the annodizing company strip it for you before they annodize the part.

If you have to do it yourself for some reason, I've heard vinegar will remove annodizing without too much risk of damaging the part. You can sand it off to with care and patience.

Good luck.

I was gonna have Hillock Anodizing in Philadelphia do it. I should just call and ask them about it. If it's something easy to do, I'll do it myself. But if they can do a better job, and for cheap, I'll just have them do it.

[Shodan]

I think they'll have to strip the part anyway to prep it so the cost should be built in to what they're charging you for the anodizing.

[cdi]

I have a bucket of fine glass beads here- it's not much of a job to switch them with whats in the cabinet now.

It might be a waste of time though, whomever you send it out to will re-blast and clean it before they anodize it anyway.

[bac0nfat]

I have a bucket of fine glass beads here- it's not much of a job to switch them with whats in the cabinet now.

It might be a waste of time though, whomever you send it out to will re-blast and clean it before they anodize it anyway.

Sean, I've wasted so much of your time already, I'm not going to push my luck any further!

[cdi]

Hardly.
I like your one-off Beretta project.

You are welcome to the beads-
Be sure to post picts when its complete!

[bac0nfat]

Hardly.
I like your one-off Beretta project.

You are welcome to the beads-
Be sure to post picts when its complete!

Will do. Do you still have that screw laying around?