It needs to be black!

[ramius-ii]

Hi All!
I am not sure if here is the best place to ask this or if it belongs on a different board. I need to coat the inside of a 3mm brass tube with as flat a black as possible. I have tried paint, a chemical etchant and nothing seems to work! Paint ends up being too thick and will scrape of easily, the etchant seems to form a "powder" that easily rubs off and becomes airborne. Plating seems the next logical choice and I have no idea what material to use as a black source for the process, plus I ahve never done any plating! Any ideas or suggestions?

Thanks, Ed

[chips]

Try one of the Caswell

Try one of the Caswell Plug-n-Plate kits, they have a black chrome kit. The kist include a power supply, solution, and gear to do simple plating jobs. In your case, I'd dip plate the tube; connect the alligator clip to the tube, immerse it in a conatiner of solution, and immerse the wand into the solution.

[ramius-ii]

Thanks! Two great ideas! I

Thanks! Two great ideas! I would wonder if something called "Black Chrome" would be shinny or flat finish?

Best, Ed (AKA WB6NSN)

[Wheelerdealer]

Would this be for a

Would this be for a scope ?

[ramius-ii]

Hey Ramesh!
How you been? Of

Hey Ramesh!
How you been? Of course, now that the whole prescription thing is solid. I figured aluminium was too flexable and one company said they would provide the parts for $2,000.00 so now I am back to doing it myself as time allows. I may just work with the eagletree people for the rest.

Best, Ed

[gerwalk]

Electroplating won't work inside a

Electroplating won't work inside a 3mm diam. tube...unless it is just a few mm long (current lines don't flow inside a conductor, you need to place an anode inside and at that diam. it would be somethig tricky). On the other side, an electroless process can do the trick. Not sure if a black finish is available.

The guys at finishing.com have some other "solutions":

http://www.finishing.com/227/92.shtml

[JWLaRue]

Perhaps a black plastic tube

Perhaps a black plastic tube inserted inside the brass tube would work?

-Jeff

[Guest]

Perhaps "gun black" used on

Perhaps "gun black" used on firearms,its to go on steel and blacks the steal and is very duable a molecular conditionig not realy a coating.
Gun smith have it,just a guess aplication.

Dave

[ramius-ii]

Thanks Guys,
Some really great ideas!

Thanks Guys,
Some really great ideas! Anodizing presents the problem of being able to anodize inside the tube as it is a reverse electroplating process where you draw material from the brass to lead and would be perfect if it were possible. The chemical processes such as gun blacking are subject to "out-gassing" that is the coating continues to produce a gas which will coat the surfaces of the lenses. A black plastic tube is a great idea and I have not found a tube material that you can use adhesives on as most are a derivitive of teflon plus the edges of the tube where the lenses are located must also be black to avoid a phenomenon called "flairing" (trails of light and color off the primary object). I certainly appreciate all the support and wonderful suggestions.

Best, Ed

[chips]

The Caswell kits have an

The Caswell kits have an optional fine point detailing wand that allows you to plate inside a tube for a distance of about 1/8". I've plated the inside a 1/4" tube about 1/8" for an exhaust on a boat model.

[ramius-ii]

Thanks Bob and I am

Thanks Bob and I am trying to go about 3.5"

Best, Ed

[Guest]

Try perhaps a metal working

Try perhaps a metal working shop that does custom work,they might have some ideas.
Even an opticle equipment maker or that type of enginners might help.

Dave