Flat grey coating

[SFTB]

Hello,

I have a very special application where I need to coat an aluminum (6061-T6) part to reduce the reflection of light/laser on the surface.

Flat Grey paint is not a solution because it can chip and also because the coat thickness is non-uniform on the part.

I already tried anodisation with a grey color and the resulting surface was still to reflective. Right now, I sand blasted the surface of the part and tried anodisation again. However with this technique, the abrasion has removed all the sharp edges and has also affected the tolerance on several areas on the part.

Any coating/treatment suggestion would be appreciated. I can also change the material I used for the part. The only requirement is to have a thin flat grey finish that doesn't have a metallic shine. If possible, the treatment must not affect the dimensions of the initial part.

 

[CoryPad]

How about zinc phosphate. It is a flat gray color, thin, and works on a variety of metal substrates.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[rhodie]

Powder coating may be an option, but as a paint guy:

A traditional paint may still be your solution. The difficulty lies in selecting the proper one. The problems you mentioned - chipping, non-uniform film thickness - can all be prevented through the proper surface prep, paint selection, and application process.
"Dead flat" tinted deglossers are availible. One I've seen is loaded with very fine diatomaceous earth particles that knock sheen to nothing. Deglossers also serve to promote adhesion, which may help in your application.

 

[IRstuff]

What is the nature of the reflection that you are trying to eliminate? In somes cases, the correct solution is to use baffling.

TTFN